Greetings Folks,

I have put in my time reviewing different projects, resources on this fine site. Decided if I am going to go through the process I might as well share my success and or failure with anyone interested.

I just finished an interesting pdf posted on the site. A deterministic process for evaluating design option towards a specific outcome. It's an MIT Doctoral thesis that seemed to fall under philosophy. I guess at MIT the technical component is assumed. Of value I think it provided a good structure/methodology for developing a CNC machine. Kudos to the poster and the writer. Coverage of beams, solids, tubing, finite element analysis, pugh charts, damping were interesting.

Thanks to Joe and Mr. Steele for sharing their projects.

One thing I notice that there is an expectation by some to have everything figured out in the beginning. I find that problematic since in many design cycles I have seen The process is iterative and a change in one feature changes the others.

Anyhow enough intro.

The goal:

Universal Platform- the capability to work with a variety materials and project sizes within reason. Expandability within reason, additional axes, fabrication methods.

Honest 8' x 4 x 2?

base welded steel tubing (on hand) concrete dampened, torsional box upper frame with basin, polymeric concrete work surface.

ball screw, linear slides (fabricated where possible) determine most affordable compromise

capabilities: standard woodworking, rough lumber milling, green concrete, aluminum, mild steel, FRP Sectional mold prototyping.

Target Initial investment for base platform $2,000

You lost me at $2000. That's an unrealistic number for the machine you described.

I can see your point. To some degree it is based on materials on hand. A better way might be saying my incremental investment. I'd say I have 90% of the structural components which leaves ball screws, and drive systems. I'm looking to fabricate the initial linear slides in aluminum.

It may be unrealistic but it is a starting point. I probably have a couple hundred feet of steel pipe (schedule 40 type) mig welder 20 inch band saw aluminum capable. 2 1/2 hp router. Pentium desktop system (using laptops).

So the goal is use materials at hand with carefully chosen bargains.

The X will be driven by a single screw below the working area in its own torsion box.

The major goal here is rigidity.

Nixed: The four pipe construction is intended to approximate the mechanical characteristics of a 6 inch square tube.

Nixed: The four slide design on the long axis is designed to give three point support and allow stability for a long z axis.

By committee ; ) it was decided that the pipe method was two challenging to maintain true and square dimension, beside being a lot of work. The value of the lower slides and ballscrew placement was similarly thrown out for the conventional dual screw method.

First images include revision to 4" frame 2" gantry. 4 inch gantry material looks really odd.

Obviously with the different design I need to consider ballscrew placement and if I want to shield the rail, ballscrew. Since these haven't been pinned down I focused on a first pass design. On my own review it needed some additional span support.

Did the concrete and rebar reinforcement experiment last night, giving it some time to cure to measure improvement using the pretzel pipe.

Bought a chopsaw, Taskforce ain't bad for the money, smooth movement, good clamping, ok angle setting, I can make it bog. The cuts are far better and feel safer than using cutoff wheel on grinder.

Miss the pipe barge a little but not too much.

wow ,you have some serious cutting and welding ahead of you

Yep,

Was thinking the same :) . I'm going to try some 1/10th scale for feasibility to optimize and minimize the complexity figure out how to incorporate missing structural detail. Jigging, and a tool I recollect for mating round tubing might make it tolerable. It seems it is always hard to get away from the chicken and egg problem.

Today I'll do a little experiment to what the deflection rate is for the 1" steel pipe I have available and see what magnitude of stiffening etc I get from the design, addition of internal concrete dampening. Should be interesting. Still looking for post on pdf mentioned. Will put under resources.

Resources used in this project

Rapid Machine Design: Key topics: Deterministic Design process, Finite Element Analysis (FEA), dampening http://www.mech.utah.edu/~bamberg/research/PrinciplesOfRapidMachineDesign/Principles%20of%20Rapid%20Machine%20Design.pdf (200 pages worth reading)

http://oneoceankayaks.com/madvac/madvac_index.htm High Precision 4X8 Metal capable
https://www.onsrud.com/home Specialty End Mills
http://www.cnczone.com/forums/showthread.php?t=8813 Ball Screws

http://www.rockfordballscrew.com/bss.htm Ball Screw Selection

:withstupi Steel tubing:

Did some very basic analysis on the characteristics of the steel tubing. Outside diameter approx 1 3/8" wall thickness 1/8". Approx 1.5 pounds per foot.

Method: spanned a 6ft section over two uprights with two commercial buckets set 16 inches apart with a home made plumb. Measurements done with cheap mechanical ruler. Measured filling with water and removing water, consistent in both directions. Some increments interpolated since the process was a bit tedious.

Did a quick measure with 1/2 the span and the deflection decreased by more than 1/2 (approximately)

Next step add concrete then rebar. Then test actual design. Will probably do harmonic test and dynamic test if possible.

Conclusions were that an unmodified pipe with large span did experience significant flex under higher static loads. At approximate 100 pounds the 6 ft length flexed .186 inches. So I'm more comfortable that I am not overbuilding unecessarily.

Had a small epiphany today on how to measure deflection in an easier fashion. As Dr. Evil would say "Laser". I have a "mini laser" from an air rifle. set perpendicular to pipe and center. Parallel might be more interesting. Mark initial level then just add water and mark the movement. Might add a glued on flat marking piece to simplify measurements.

Never found that damn "laser" but I did find a local steel supplier who has what I'm looking for at the right price. The steel composition and characteristics need to be figured out but this what I found a the Metal Mart.

Damn have my quote for roofing but not the steel prices. It's primed and inside at least it looks cold rolled.

Anyhow 4" x 4" by 24' 11 gauge ran $76

The base works out to $234 with tax
rebar and concrete will be extra

$40 for rebar
$40 for concrete (horizontal structures)

So I expect when it's said and done approximately $500

Below is a first pass spreadsheet which should allow you to compare desired features versus expected version capabilities
2nd pass

Use one large steel tube instead of that small tube welded truss. Don't you realise steel bends where you weld it !

That thing would be bent and twisted like a pretzel.

I, personally, can not imagine welding that thing up and having it resemble anything other than a pretzel - especially with many of the tubes having welding performed only on one side down the length. The structure will resemble a bannana unless you have serious fabrication experience. Just my impression.

Scott

Appreciate the feedback. I am aware of the deformation. Honestly I haven't done much work with steel in a long time. Aluminum is much easier to cut, bit harder to weld. Haven't found a reasonable tig, but for this it would just take longer.

I know someone who used square stock and the cost based on his comments was probably around 2k. In the end it showed some signs of lacking rigidity. I'm challenged on a number of fronts but am evaluating some methods which will overcome some of the sows ears and chicken and the egg issues. Yet to be proven but there is reason the steel will be less likely to deform, less likely to need to be destressed. I'll have to assemble a portion to see how much cross member support will be needed.

The pipe is actually drawn as 1". The pipe I have laying around is 1 and 3/8ths 1/8th thickness. Looked like 1 inch to me. It's free and I have some larger material although I believe I partially buried it with front end loader.

In the PDF under resources I recollect the concrete formulation they used expanded. The rebar should have some insulation from the welding and provide additional rigidity. (added excerpt). for pound dollar for dollar round stock was better than square in terms of handling torsional forces and overall. However, it acknowledges as I will square is more practical for mounting additional hardware and of course fabrication.

I can rent a plasma cutter for $60 a day and purchase a chop saw. I'll finish up with the sand blasting at $160.

Been finishing an Acre of pond and considering my options. Making the workspace a better place, my girlfriend calls it a garage, is another project. Been a homeowner for year, had to quit the dayjob to take a vacation and to get some work done around the house.

30685

30686

:cheers:

Well, I might as well jump in here :)

I'm just finishing up my mill, it's overall dim's are 20 x 10 x ~5 feet.

Reading the first bit of your thread several things come to mind.
1) If your serious about producing a high end router, the money you've set out is about 10% of what it will really take to do the job. Your linear rails are going to cost you ~ $3000, that is unless you plan to buy little pc's off ebay, in that case.. it'll be a real struggle to get any precision.

I realize you have lots of mat'l already in hand, but I question if its the correct mat'l. Someone mentioned larger tubing, I would give some SERIOUS thought to that point.

2) It would appear that you've taken a simple fixed table design and extrapolated it for size. I'd re-look at that design, having a center drive for that large of a gantry is just not going to work, it will be one racking headache after another. Dual drives from either end of the gantry is the ONLY way to make that work decently.

3) Check out the 'Polymer Concrete' thread, there is some very interesting dicussion on how to build larger structures which are flat and will give planer rail mount surfaces. If/when I build my next machine there will be some changes on how I approach my build/design, based on this info.

4) The less welding you do, the better. If you came make use of large structural sections instead of little pc's [ like 1" dia pipe] do so, cutting and fitting that 1" pipe is going to drive you crazy and as was mentioned.. you'll end up w/ a nice large curvy pc of art, not a router table. If you've ever bellmouthed and fit pipe, realize that doing it for a router table is going to be that much worse. [just laying out the cuts is a huge PAIN]

5) Buy the tools you need, renting the plasma is fine, but get decent machinist tools for layout and what not. Precision level/type tools are a must.
[again budget several thousand dollars]

I was where your currently at about 1.5 yrs ago and have learned much since then [mainly the hard way :)]. I was a little more conservative on my cost estimates and came out w/ ~$10k. Later I changed up to linear rails and really started looking over how well my idea would work and realized that alot more had to be spent to get a decent machine. So far I'm WELL over three times my initial estimate. Can it be done cheaper, sure but not a whole lot. If you want 'high end' then there is a cost that goes along w/ it.

Keep at it, and realize that there is ALOT of help for offer on the forum [ and no I'm not talking about my presence here :D] there's lots of great people on here!

Ok, I'll get off my soap box now :D
Jerry

LOL,

I've already looked at some bigger materials. After bellmouthing 1 piece of pipe with very primitive means I was reconsidering a number of things. Free in this case means free to do a lot of work to make it work.

On the single ballscrew, wouldn't the double lower rail help to keep things in alignment. The racking concern was why I put them there. Not sure about the interaction of span and screw diameter more sag more problems.

On the bigger materials I probably went too far in another direction and saw some thinner gauge large diameter pipe which could get most of the strength from the rebar and concrete but decided the guage was too small.

Yes, from reading a lot of posts I got the feeling that improvising to save money many times ended up creating headaches. So yes I did try to discern what worked or what would work. The higher end was not meant to be a put off only that I would go with higher end linear systems.

P.S. the post in the linear section wasn't what I originally wrote, seemed a reasonable substitution. Had a crazy idea that on reflection had some serious merits. Last time I had a more reasonable idea on a web site I saw a major manufacturer come out with it a year and half later. Probably not feasible but if it was it would be worth checking into.

When I bought my two phase welder I bought a book, the most common one. Tacking and filling in small sections and would guess transverse sequences would be how I would address that issue.

I would have thought that being in the US it would be very easy to buy second hand steel beams very cheaply (U channel or H section, can't remember the English names anymore, RSJ?). If weight isn't a problem then I think that would be a better route. I have made quite a few race car chassis using notched tubing and Tig and if you are set on continuing with the tubing you will gain considerable strength by adding triangulation. you only need thin wall small diameter tubing for the triangulation, 1/2" or 3/4" is enough.

Good to hear, I'd stay away from round pipe completely if possible. But then, thats just me.

The bottom rails are just a waste of time and money, because they are located in the same plane [along the y axis] and are not staggered down the length of the x axis [at least not by a noticable amount] they are just wasted use of rails. Judging [scaling] by the size of your rails, they're good for several thousand pounds, the two up top on the x and the two on the y are more than enough. The rails rating will FAR exceed your strutural rating [FAR meaning the rating is over the horizon in comparision]

If you have to drive the gantry from the center, the only way to make it work w/ and reasonable expectation for success, you'll have to space the trucks/carriages on the x axis by at least 1/4 of the length of the Y axis, this will still [probably] not be enough but will help. If you want to illustrate this, take a ruler and place it on your desk/table. Its pretty easy to move it w/ your finger in the middle pushing across [ 90degrees to the length of the ruler], now put a tape measure [or something of comparible size/weight] in the way of the ruler, try and push it, when it hits the tape measure, all it does is twist outta the way, watch as its twists, see how little the center of the ruler 'moves' compared to the outside edge, this is the exact same way the gantry will react when you start using a tool in its spindle. The tool force is going to twist the gantry outta line, the center rails aren't going to help one teeny bit. Do the same experiment but grab the ends of the ruler and only allow them to move the same amount, hits the tape and doesn't twist outta the way.[there I just saved ya buying 33.3% more rails than you need :)]


Driving the gantry from both ends is really a non-event. The control of the motors is taken care of by the motion control software, the only part that is a negative is the extra motor, wiring and ballscrew or whatever your using for a drive mechanism. However, on the upside, you'll still have hair after you get it working..[assuming you started this project w/ some :)] If you take the extra rails off, you can more than compensate for the added cost of a motor and drive.

Your right about improvising to save bucks, its all about what your time is really worth, AND how badly you want your machine to work correctly. If you build it wrong today and have to fix it tomorrow anyway, it's gonna cost alot more to fix.

This reminds me of the 10x rule.
If your supplier makes a part it wrong & costs him $1 fix. If the part gets to you and you find its wrong [on delivery] and have to send it back it costs $10. If you get it welded into the structure and ready for delivery and then find its wrong, it's $100. If your customer gets it and finds it its $1000 [all from a $1 part] Some will argue its the 3x rule, whatever ... the point still stands.

I missed the post in the Linear section but will go take a look @ it.

Sometimes people have great idea's and lots of people don't think it will work, this is true. However I'd sure hate to hear someone spending lots of money on something, only to find it doesn't work. I've done this myself, but then.. I thought I was smarter than the other guy.. until he proved it wouldn't work.. all he had to do was let me try :D

Welders are so much fun eh? I've taught myself to weld.. I'm not no expert/papered welder, but may stuff doesn't fall apart when hit w/ a hammer [anymore..] I trust its a mig?

Also, realize that building this machine is going to frustrate the heck outta ya, [as well people offering their advice :D] but if you keep at it, you'll be amazed at what you can do, even w/ little to know experiance building stuff of this nature!

Jerry

Skippy,

On the reclaimed metal, good idea I'm going to check it out My uncle works or worked for pretty big salvage company here in town. Used to get some copper and other stuff. I'm sure they do steel. Just have to be straight and relatively good shape. If that doesn't work I think there some abandoned rail road track about a mile from here (%

The cheapest steel runs around $2.50 per pound per the metal supply here locally. Taking that route I would need to figure out how to maximize the investment.

Jerry,

Thanks. need to find a ruler and absorb what you said ;). I'll send you the concept, then you can laugh, and I'll move on to something more productive.

Sage, I'd think you could get Steel cheaper than that. I bought all my Steel for less than $1/# here in Canada, most of mine was HSS which is going to be the most expensive. I've got lots here that I'd sell for $2/lb :D

Btw, don't take my posts as crusty or poking fun, I'm only posting to help. The ruler illustration is pretty self explanitory but it breaks things down to the basic entities

I'd love ta see your latest concepts!

I can honestly say that I wouldn't be where I am [on my project] today w/out the help of the people here on the forum. [ I'd probably have given up on the whole idea and be sulkin :)]

My applogies if I came across as talkin' down or anything..to me there is nothing more gratifing than helping others succeed. I can honestly say there is nothing more I'd like to see than someone like yourself taking the 'CNC bull ' by the 'proverbial horns' and winning in the end, on the first try as well!

Jerry

Skippy,

Not giving up the small tubing in general but in this case going big is a lot more expeditious. I wanted to add some triangulation or transverse? stiffeners but felt I had already painted myself in the corner.

Still would like to find a good TIG but for now I'll sharpen my MIG skills. I dropped about $600 on a lincoln. Told it wouldn't work well for aluminum, took some time and more than few burn throughs and now have functional weld though not as pretty or precise as TIG.

Building a monocoque race type frame would be more than fun or something baja type.

Well as I told Jerry it was good to be talked down from the pipe. I can start fresh with a more fundamental approach that doesn't revolve around what's laying around. Get the work area in order.

Thanks.

....Told it (MIG) wouldn't work well for aluminum, took some time and more than few burn throughs and now have functional weld though not as pretty or precise as TIG. Thanks.

Nor is the welded joint as strong or durable as a Tigged joint. MIG has inherent issues that become severely amplified when welding relatively thin aluminum (less than about 1/4"). These problems are completely unavoidable with any MIG machine currently available, but that's another issue altogether. The biggest downfall of MIG is cold start which is not an issue with TIG.

Whomever told you MIG would not work well on aluminum was correct and well experienced. It is easy to find someone relatively new to welding that says it is done all the time but it is impossible to find a certified, structural welder that will tell you it's efficient or well-suited for structural type work on thinner sections. The story is different when your thickness goes up, but crack propagation is still a huge factor. If your design is robust enough to deal with a seam that is less than 50% as strong as the parent metal then Mig will be fine for you. For a while, that is. Eventually, if the joints are stressed they will begin to fracture.

If you are welding aluminum frequently or doing a lot of it, do yourself a favor and save for a TIG or lease one for the project. I have been down this road before.

Scott

Oh - glad to see you back, Skippy! Long time no see!

:cheers:

Jerryflyguy,

Well luckily I've never been misinterpreted or misunderstood ;) Clarity and simplicity are my middle names.

Steel eh? I don't know the conversion rate but imagine at $2 canadian we'd be talking. I have high expectations, I ordered one 115 Honda from Bay Marine or something like that. Decided it was too big sold it and ordered a 50 and got another 115. Thinking I like these canadians. Straightened things out of course.

Only thing on my mind right now is pay those property taxes online today, cook up some salmon. I'll revisit your description, I know it made sense but I truly wasn't in the cnczone.

Jsage

mxtras,

Yes found out after the fact. It says right on the box welds aluminum: ) You are right, he showed me a tig weld that brought tears to my eyes. What really got the tear running was when he told me I'd need to drop about $2,500 for a tig with good functionality (technology). Scouted ebay and everything looked like it had been in a war zone.

Position is critical the feed is sketchy and you can get a decent weld on one side and a surface weld on the other.

Exactly. The process is rediculously picky. I can lay down a beautiful weld with a spoolgun but I can not do it everytime, guaranteed. With TIG, you can.

Many years ago, I spent a lot of money including hiring a guy out of Georgia to come to Virginia to school me on Aluminum MIG. This guy was the best of the best Migging aluminum and welded aluminum dump bodies 8 hours a day. This attempt alone cost me $1500 just to send him packing on the second day.

My next door neighbor welds exotic metals for a Navy contractor and is certified in just about everything, including nuclear components. I think he knows what he is doing and apparently so does the government. He had never Migged AL but thought it would be worth a try and since I had a brand new Mig machine for that purpose, I brought him over for a little break-in session. We got limited success pretty quickly but we could never find consistency. He was disappointed at the results, also. So - I knew at the time that it wasn't me and I was begginning to suspect the machine was faulty.

After a lot of research and trials, I decided that I was not happy with the equipment and I went to my supplier. He scheduled a welding "expert" to come out from Miller's Headquarters. This is a humourous story. A week or so later, the guy shows up, gets out of his rental car and walks in as if he was a super model walking the runway. Nice guy, but I couldn't help but think that he thought I was an inexperienced, amature weldor and this trip for him would be a quick waste of his oh-so-valuable time. I had prepared material ahead of time, so he proceeded to check out and set up the machine, put on his $450 custom Miller auto-darkening helmet, he grabbed two pieces of material, threw them together at a right angle and he ran a bead. It looked pretty damned good. I spin the part around, cranked the settings to my preferences ( quite a bit hotter), slipped on my $60 old school, large window shield with a high performance (sic) gold tint lens and ran the same quality (from a visaul perspective) that he ran with less spatter than the run he had made. I think his ego was a bit damaged at that point, but we continued. We were running a fillet weld and I told him that was not what I was having problems with as the current settings were pretty high. I set up the next joint configuration, which was a prepped, double bevel butt weld in 1/8" tubing - my most common seam. Despite my insistance that he make an effort, he did not even attempt it - he simply stated "you need a TIG". He offered to buy back the dual gun MIG and credit it towards a TIG. I kept the MIG and bought the TIG. One can never have too much capability!

And - just like any other time I get a chance to pimp my machines, here they are. This was taken about 2 years ago when the TIG was pretty much spanking new. Those walls aren't that white anymore, by the way....


Sorry for the ramble.....

:o

Scott

mxtras,

I just misclicked on your profile. Read your thread. Looked at your setup. Simplicity good tools and bare concrete.

No doubt your a goldmember.

Jerryflyguy,

Generally, I'd say my posts could be a little crusty and poking fun. It is hard to breach the subject of bad design concept or a vague question. I realize your talking US dollars but I'm purposely being obtuse.:rolleyes: That is a considerable difference in price. Houston about 3 hours away is where the supply company sources their steel. Newell Salvage apparently doesn't create finished materials. So I guess I can shop around for prices. I got the ruler analogy even though today I have headache:cheers: and don't remember why. I can modify your analogy to a harrier jump jet vs and osprey or dual rotor helicopter.

Mxtras,

Good story, with aluminum, MIG does but it doesn't. I spent a month evaluating TIG options and have probably forgotten more than I remember. At the moment I'm trying to remember whether it is AC or DC that allows you to weld alum (DC probably). I like your work experience sounds interesting, traveled around a bit myself and have a strong interest in composites. Originated with naval architecture study or a fancy word for boat engineering.

So today I'm going to reread that design manifesto as a primer. Has organized a lot of the design calculations. I'd imagine most would find it academic but I see some value in it. Will check out out the polymeric concrete as well. Did a bit of research in that area basically because concrete and faux rock fabrication seems to have a lot possibilities.

As for me my background is as a generalist, finance background, market analyst, business and financial analysis, electronics (communication industry), Biotech and most recently Durable Medical Equipment (DME).

My interests are in composites including high tech, robotics, and just about anything in on top of or under the water ;)

naaa didn't notice any crusty :D.

On the steel I was actually talking Cdn dollars so USD should be about 12-15% cheaper.. What you need to find is a steel supply that doesn't mind selling smaller quantites. We have such a store not to far from here and their prices are great for little bits of this and that, esp when your talking high dollar stuff to begin w/ [ 11" 4140 shafting or something] Not all steel supply companies are excited to sell to the 'little guy' so they charge just stupid rates and if a person didn't know any better, they'd pay it 'cause thats what it costs right?'

The ruler test applies to the Harrier Vs the Osprey to a point. The hairier [pun intended] doesn't sit on just 1 jet nozzle however, it has 4 as well as jets on the wing tips and tail. This makes its a bit more stable [ it wouldn't fly otherwise] and that new 'thing' the military is building down there is going to be even less stable as it IS flown on 1 center nozzle w/ a couple tip jets.

There are alot of people kinda Pissed off over the Osprey, I'm not sure why as I think its kinda neat, but then it's not my tax money, no my boy's flying it.
Strangly enough its apparrently VERY unstable when transitioning from forward flight into a hover [through ~100knt it gets VERY unstable in pitch], not so bad going the other way.

Anyway, enough about airplanes.. [I'm a part time Corporate pilot, so I can talk about them ALL day.. :)]

I'm no expert welder, however I do work in a certified welding shop [telling welders how to build stuff, t'is my day job [full time]] We weld Alum pretty regularly w/ the 10lb spool gun, but its no TIG weld. However we choose to use the spool as its easier to 'get onto' than the TIG for new welders. The TIG has several welding issues which take experiance to correct, and TIG is usually alot slower than the spool gun. Having said all that, we all prefer the TIG welding when we can get it, the project can look THAT much better and usually crack THAT much less, but then the customer has to be willing to foot the bill as well.

I currently use a 110v mig at home [sucker pulls over 20amp's and is constantly blowing the breaker if its 20a or less] but hope to upgrade to a nice MIG/TIG in the near future. In the mean time it does what I need just fine. Welded some 1/2 pl last night all it takes is a bit of a bevel to get full penitration. [suprisingly enough as its kinda a ratty old thing :D]

Jerry [ FWIW from a in-experianced welder.. :D]

Guys if you need AL or steel go here http://www.metalsupermarkets.com/ they cut the parts to your lengths and have both AL and steel and the prices are good. The little stores are everywhere including Cananada and US but use the store locator and I think you can have it shipped from them also. Just call the order into the closest store to reduce the shipping.

I have been reading this thread and need one point of clarification... If I want to weld AL I should get a nice TIG machine which in turn does steel just fine. If its thick AL then bevel it (used to do sched 80 1.5" thick pipe fitting so no prob there)

Do I have this right???

Coog

In any given weld the TIG will be slower than MIG, but then faster isn't ALWAYS better.. Metalsupermarket is a ok place to buy. I've used them but I'd contend that the pricing isn't the best. However if your looking for something REALLY odd, they'll have it.. but then you'll have to pay for it as well [if you get my drift]. Your better off going to the local steel supply and buying there instead of the 'supermarket', in my opinion. If the entire design required some exotic profile or size mat'l then I'd re-evaluate the design and make it work with something a bit more common.

Jerry [I only purchase ~$1-2 million dollars of steel a year so I might be wrong :D]

I can shop metalsupermarket and I think I will from now on. I am not worried about speed in the welding only that the welding is strong. I have never welded AL and would be interested in buying the right machine. Do you a link or 2 for machines recommended for 1/4 to 1/2 AL and steel?

I am the student so please share the education.

Thanks in advance.

Coog

Hey, did a quick redesign for general characteristics. I've been looking at allmetals.com? Discount and shipping not bad, cheaper than local I believe haven't done in pounds calcs.

I'll check out that site coogrr.

Well student :) I'm no authority when it comes to spec'ing welders.. The model I use isn't available anymore. If I was to buy a 110v mig again it'd be a Lincoln135T [ I see they are coming out w/ a 140 series. The 'T' model is the cheaper one, if you want infinant control of your heat then get the 'C' model]

When it comes to TIG, I really couldn't offer to much of an opinion. If you want you can go here[http://www.mylincolnelectric.com/Catalog/equipmentseries.asp?browse=101|207| ]to see the different options and decide from that what you'd prefer.

Jerry

Coogrr,

I'll give you my two cents A mig is probably a better entry level for all around but to weld aluminum you can add $500 for a spool gun. My welder is a basic lincoln 175, a higher end model would do a better job. As sold you have to buy an aluminum kit which gives you nylon inserts and a feed roller for aluminum. I got around it, kind of by keeping the welding feed line straight, not overtightening the feed tension and using vaseline intermittenly to reduce friction, no jokes please:) The basic analogy is trying to push spaghetti through a small diameter pipe. there are push pull systems but again cost is about 50% of what you payed for the welder to begin with.

Still comes up short in my mind. I tended to create more cross support to address less than perfect weld strength.

A TIG requires two hands and a foot for controlling the TIG. You can get a low end TIG, Hobart EconoTig or something like that is prices in the $1000 plus range but the higher end features like weld start, square wave, pulsed etc ends up being considerably more expensive.

This is just a vague recollection, there are various technologies.

Oh boy. Here we go....

Simply put, the Econo-tig is useless for AL greater than 3/32". You will max it out just to get 1/8" thick material started and the duty cycle will kill you.

To keep from distracting this thread again (I think I did just that earlier) - go to the Miller/Hobart forum and dig around. This topic comes up not less than 657,432 times each week. Ok, not quite that often, but the "Which Welder" question is rediculously common and it is a bit of a complex question to answer. Go to http://www.hobartwelders.com/mboard and spend a few hours digging around.

Scott

mxtras,

I don't think you distracted from the thread. With a larger welded frame this is good stuff to know.

I wasn't enamored with the econotig, didn't come across that limitation. I have all the models specs catalogues so if I could find a decent used I'd know what the stated capabilities are.

However, it's more worthwhile to know what works in practical apps. The marketing materials aren't as clear as they should be. I'll do a steel and aluminum weld tonight for grins, maybe it can be poll asking how these welds look.

Ok

Don't Suck

Suck

Perhaps you should look for a weldor or use bolts?

Remembering now new econotigs run around 1700 new on ebay. Why I guess cause you don't buy them to weld aluminum.

Hi jsage,
Firstly, great thread. My next machine hopefully will be my large welded frame router, so all the posts are very useful. :cheers:

Im buying a new Mig soon, thought I'd have it by now but it is a bit delayed, anyway, I decided on the Lincoln Electric 225 Mig. Hoping I'll be able to do aluminium from about 6mm upwards, although I never mig'd aluminium b4. For the aluminium Im getting a seperate torch with shorter cable, and teflon liner. Also use a slightly larger than standard tip to allow for the more rapid expansion of the aluminium wire. Now before everyone jumps down my throat :D, I was initially looking at a spool gun, but I've been told by many people here, including the guy selling me the machine (Who Im sure would like me to buy an expensive spool gun) that this setup should be fine if Im not doing lots of aluminium every day. If they're wrong I'll ask for my money back on the torch to put it towards a spool gun. m2c.

mxtras, on a totally different point :rolleyes:, that pic above is one of the ones that I pm'd you about, and the machines I was talking about. :)

L8rs.

thnkoutsideofthebox,

well I concede on the alum welding. I need to buy the kit. The spool was low so it was overtensioned, had to clean up the filings. Did a test weld and it was too thick. Turned up the voltage and did the weld but the feed was sporadic. Started out alright then was pretty much flat. I bent the beveled 45 I did in flat stock and suprisingly the weld was pretty strong but a grinder. My setup without the lining and drive wheel is nearly impossible. I bought the 110v the first go round and returned it. Didn't have time to usethis one it for a few months so I'm pretty much locked in. I'm going to see if I can return it tommorow.

To be fair, I cleaned up the gun, loaded a new spool and the attached are my H.R. Geiger welds (The guy who illustrated the alien movies). I swear most of the problem you see is irregular feeding. Second is superheating of metal, third is me.

Steel selection

http://www.onlinemetals.com/merchant.cfm?pid=10376&step=4&showunits=inches

Hot Rolled Mild Steel Square Tube A36
Dimensions
Dimension Name Value
Height 4"
Wall 0.12"
Internal Dimensions (implied)
Height 3.76"
Please note that the internal dimensions are calculated values. Since they are determined by an implied method, and not produced to these sizes, we cannot guarantee them.

(Technical information is located at the bottom of the page)



Hot rolled

Weight/lineal foot: 6.3311 pounds

ASTM A36 Mild (low-carbon) steel
Minimum Properties Ultimate Tensile Strength, psi 58,000 - 79,800
Yield Strength, psi 36,300
Elongation 20.0%
Chemistry Iron (Fe) 99%
Carbon (C) 0.26%
Manganese (Mn) 0.75%
Copper (Cu) 0.2%
Phosphorus (P) 0.04% max
Sulfur (S) 0.05% max

cold rolled chars for comparison

1018 Mild (low-carbon) steel
Minimum Properties Ultimate Tensile Strength, psi 63,800
Yield Strength, psi 53,700
Elongation 15.0%
Rockwell Hardness B71
Chemistry Iron (Fe) 98.81 - 99.26%
Carbon (C) 0.18%
Manganese (Mn) 0.6 - 0.9%
Phosphorus (P) 0.04% max
Sulfur (S) 0.05% max

10% discount for 200 ft $45 standard delivery works out to $ 1.91 a pound

Local source primed mexican steel works out at $.54 per pound

I'll use higher quality steel for gantry. I'll use the above unless someone convinces me that reinforcing and dampening this lower quality steel is a bad idea.

jsage, I hope you dont take offence, but those welds look almost as bad as mine when I started my welding course last September. :D

I'll reserve my offense till you tell what kind of setup you were using. My steel welding looks about 10x better. I gave up on presentation, this was midnight madness welding.

I'll go even one better...or worse....my first weld was on steel! :o It was soooo bad :(. But I've come a long way since I started. :)

10mm plate with an 350amp multiprocess machine. Lincoln make them, cant remember what its called just now...its on the tip of my tongue...arrgh! At the course last monday before going home, just to increase my expereience (Read: "fun") I flipped the wire feed and voltage settings up to the max and shot it 90deg straight into the plate. Burned through in a few seconds and made the worst mess of my piece ever....dont try this at home kids. :D

Jsage, those steel spec's are fine, I built my whole machine from 350w mat'l [ really its no different than A36, I've never bought a A36 HSS or W/S or C section.. it's always been 350w.] If it needs dampening because it ring's then fill the sucker full of concrete, that will stop any ringing :D.

Jerry [I still say $2/lb is too much.... :)]

http://www.cnczone.com/forums/showthread.php?p=252373#post252373

Outsidethebx,

I was looking for a multiprocess welder in the beginning ,XMT I think and a couple others. Not sure if that is the same multiprocess TIG and MIG.

I think the welder I liked the most for the money was the precision TIG (not multi). There are some on ebay now for $1,400. If I can return this one that might be what I get.

I tried to weld some of the home depot type round tubing I was welding before. Not sure how I pulled it off I burned through on the lowest setting and higher feed rate. Guess I was tacking along. Biggest issue I have been having is consistency. Sometimes I have a thick bead and sometimes I have too much penetration. Not to mention the feed just stops. My wild guess is with the setup your talking you'll have less problems but you have your annoying times when everything is not perfect. I can liken a push aluminum welder to copier paper handling when it gets a little off its a pain in the butt.

Cool that you took a welding course. Last experience I had was about 25+ years ago in industrial arts, very limited. ARC and acetylene welding.

Thanks Jerry,

I'll look you up for the gantry material. Do you cut it to size?? Free delivery. I know it's got to be tax free! although, customs or import tax might be a deal killer.

Glad I went scouting yesterday, remember finding this roof supply, metal building place. I don't think I can do much better than 50 cents a pound.

Cool that you took a welding course.
I had only played around with Mig and oxy-acetylene before I started the course. Was under no illusions that I couldn't weld. Barely knew one end of a welder from the other (The machine kind not the big hairy kind! :D).
:cheers: Its funny, they've been telling us stories during the course about guys coming in to the course with the "Hey, I can weld just fine" attitude. Sent there by they're employers. This is after having been welding walkways and structural members on building sites for months or years. :eek: So the standard response by the instructors is to leave them work away on some plate, which they then send for X'Ray and cut as per standard practise, to be bend tested. Needless to say those folks end up having to swallow some pride when their piece comes back from bend testing with a nice big dirty crack along the bead....I saw some of the pieces....:eek:. Also saw some from the exact same folks after they finished the course, nice bend - no crack. I say I've come a long way since I started a few months ago, and I have, but still dont know if I'll get qualified in steel plate at the end. I've learned that its not difficult to do a decent looking weld after practise, but geeze is it difficult to get it perfect every time for bend testing and X-Ray :tired: :(. My current problem is with burn through as I move up the piece, the plates (300mm) are pulling in as I weld up regardless of how securely I weld them at each end. I just cant get them to stay 3mm apart at the top, and .5mm makes a hell of a differance to your root. Anyway, I waffleing. Welding is fun. :) L8rs.

For the machine you want to build, go with the "mexican" material for $50/lb.

All tubing used in the US that is commonly available at the average steel service center is astm a513 or astm a500. A513 is called ornimental and has lighter wall thickness selections. A500 is "structural" and is available in larger sizes and heavier wall thicknesses. The VAST majority of square and rectangular tubing sold is produced to one or the other of these specs and current market value for the common sizes is around fifty cents per pound. This link has a good list of standard sizes and their weights.

http://www.superiorsteelsupply.com/sqtube.htm

Good luck with the router! I plan on building a basic 4' x 8' steel frame gantry, but will probably go pretty simple on the structure. Check out madvac.

http://oneoceankayaks.com/madvac/madvac_index.htm

Miller makes the only welder worth owning....

srstol,

good links, thats two positive votes. Added the CNC link to resources.

The CNC builder wanted some major precision, I'll have to see what he ended up with. He did a good amount of triangulation, I wonder if it is necessary. Have to take a closer look.

I need to find a translation of 11 guage I believe 12 is very close to and 8th. I'd imagine you just use 100 as the numerator. I picked that classification because it had the same weight per foot and if I was looking at worst case hot vs cold rolled I would have the right steel characteristics. When I go back I'll ask the person there if he has specs.

I'm going to start roughing out a BOM. Well move to excel when it gets more complete. Similarly I have to consider where it will go/fit. For now it will be things that don't immediately come to mind.

Limit Switches

The site Srstol provided brought up some interesting questions that tied back to the pretzel paradox. Basically he wanted to be able to dissemble his CNC. To accomplish than and have .0005 precision he bedded and created contact surfaces for the mating end of the frame.

My original thought was true the screws, gantry (moving parts) alignment and the exactness of the frame would be less critical (within reason). After reading his explanation I'm more inclined to go for a good degree of accuracy and create good contact surfaces for attaching linear systems. What always gets me is that with all the engineering I see these CNC routers sit on pin sized adjustable feet. I have a more robust Idea, I think, I used on my workbench.

So whats the idea you used on your workbench? Dont keep us guessing!!! :)

You are right. Even the majority of factory built machining centers and cnc lathes are mounted on a serries of leveling feet. This is a good thing when it comes to leveling the machine, which is critical for tolerances, finishes, etc. At least that's what some people say...

Large conventional machines typically had foundation plans that came with the machines so the owners could place the machine on it's own foundation. Most of these foundations had mounting bolts coming out of the concrete and the machine was placed over these bolts. As it was leveled it was secured to the fountation. The idea was the foundation was monolithic and if it moved, it would move as a complete unit, as opposed to the floor cracking and one leveling foot taking more or less then it's designed load.

Some of the higher speed machining centers are grouted to the floor to keep the machine from walking around with the inertia from fast rapid moves.

Just some food for thought.

Having trouble posting I've wrote this three times now. Hopefully, I have become more concise.:)

The method I used isn't overly exciting. Just cut a rounded rectangle say 3 inches up from the bottom of a leg. Big enough to allow socket wrench and bolt movement. Use a large diameter bolt and 3 plates. A fixed tube could be added as well.

Sequence is

Large diameter fine thread bolt
Nut
Welded to
Square Plate
Welded to Leg Wall level with or just below cutout
Tube (Optional)
Nut Welded to
Cap Plate on bottom of Square steel leg

Nut welded to plate or other foot type of your choosing. You could drill 4 holes in the plate for floor mounting in heavy duty anchors as needed. However you'd have to come up with a way to make the bottom bolt foot connection free floating.

Probably have to be assembled and welded as one in jig to ensure proper alignment.


Was going to add it to design but had trouble finding dwg, dxf files for free. Know there out there.

Also made me consider perhaps six legs might be better than 4.

If we are speaking of wood not plasma (water table) isnt leveling a relative thing. The cutting device needs to be square to the product being cut but if the whole damn thing was tilted 45 degress up a wall it would still cut straight as long as that bit was square to the product in the end.

or am I missing the point on the feet talk?

Coog :confused:

Coog,

My two cents, discounted value, point fify cent. Unless the router is unbelievably rigid and light if you cut a half an inch off one leg. or put a half inch spacer under one leg it would change the square of the machine slightly. This would become more critical as size, weight and precision needed increases. I'd guess the squareness from bit to cut surface would be the same on a point basis, provided you have a flexible material to be cut.

Also the original concept for the workbench was have a 100% level to be able to cast up to 4 x 8 concrete veneers in place.

:)

Well,

Looks like I found the most difficult component. Did a lot of research on these but I'll need to see em. Luckily I can make a somewhat long drive 7hrs, to pick them up, check quality if needed. Hate to ask opinions after the fact but the price was right, no more no less. I did see another pair possibly still available if these turn out to be an excellent value.

auction item

http://cgi.ebay.com/Ball-Screw-for-Fugi-CP-IV-2-pcs_W0QQitemZ290084043424QQihZ019QQcategoryZ55826QQrdZ1QQcmdZViewItem


Here is the same machine.

http://www.equipmatching.com/used_equipment/2/35/67150.php

Thanks to Jerry for the advice.

...the original concept for the workbench was have a 100% level to be able to cast up to 4 x 8 concrete veneers in place.

Or you could build that "level" into the actual machine frame using polymer concrete or epoxy/granite. Check out the thread "Polymer concrete frame" in Engineering sub-forum...

Walter,

Thanks. Been looking to revisit that thread.

On rereading recognized I had got through the first 10 or so pages then read from end backward. ; ). Needs a conclusions page. My conclusion is that people need to be clear that structural components with motion oriented stresses lend themselves to higher synthetic content/plastics military ceramics. On the other hand if you are leaning more towards anchoring structures and a cutting area substrate then you lean more towards optimizing the aggregate matrix.

In my mind some are missing the point. I can create the equivalent of 4"x4"x8' beam which will have flexural strength not to far removed from something milled out of solid granite. If I hit it with a sledge hammer it's going to break. Alternatively you go super massive which is great for machining tolerances but I wouldn't want to have to move the machine to re-organize my garage ; ).

The epoxy granite sounds like a winner. However if I ever need to modify it I will be reminded of hard granite is. I think there is a solution there for my needs I'm just not sure which one it is.

An adequate polymer enhanced concrete with a sacrificial higher epoxy, softer aggregate surface is what I have envisioned. Otherwise, spoil board or I get the alignment perfect and design the whole thing rigidly enough such that I never cut my table. ; )

If I was doing a small mill the economics would make sense. Still have a number of pages to visit. The workbench is my woodworking work bench. The leveling is actually done from the top with lag bolts.

A couple related things. The great strength of this medium is to cast not machine custom components.

Taking out a wall on the garage. Has one support in the middle that actually makes contact with roof beams. One thing I found is if you have two 8x4++ items space disappears quickly. I have a 30 by 20 space, 2 car garage with dark and dismal 10 by 20 storage/shop area. It's a project in itself.