Hi, This is my first post here. I am gradually getting my workshop the way I want it and was looking to buy a plasma cnc table. The after checking with all the usual vendor options, I had to ask why are they so expensive? So I did some reading on building my own and arrived here many times. I just want a small 4x4 table and have looked at many build threads and they all seem to take a different approach. So, to make my research more focused, what is the best design on a 4x4 table? I plan on using Mach 3 and have all the computers I need, and I want THC for sure. How many available FREE plans are available so that I can download and evaluate them? I plan on buying a mill before I start the project and already have welders etc....
Thanks for your time,
G

Let me rephrase that... :) What type of rails are easy to build but accurate. What is better, servo or stepper? Belt, chain, or rack and pinion?
Thanks,
G

for electronics part i suggest you buy the complete kit from candcnc.com

for stepper and servo it depends on what your needs are.. the stepper works really well but doesnt have feedback so it doesnt know the actual exact postion.. incase the stepper motor gets jammed or miss step u might loose a little accuracy..

one of my machine is servo and other is stepper.. so far that stepper machine works perfect i havent had problem only time i had problem is when the machine required to pause and it lost the step so i homed it and that solved the problem..

cost of stepper/servo is big difference

for linear rail i suggest you use v bearing with v railing if i had to build whole thing again i would use that instead of pillow block open bearing that is currently on my machine..

for gearing part.. one of my machine is on chain drive and the accuracy is very good.. im happy with it..

the rack n pinion is a good way to set it up.. but for the cost factor chain is very cheap..

hope those info helps

Cheers
Dan

Well their are many different aspects to consider on a cnc build. First thing is what is your total budget on a 4x4 table. Also, when do you wanna have your machine up and running? This will help get you going in the right track. Some people spend 3 thousand dollars and others spend 12 thousand. If you have a very low budget you have to cut corners on your rails/material size/cnc package etc.... Some very cheap tables cut just as good as a very expensive table, all depends on your decision making on the design/materials. Second what is your objective of the parts you cut, artwork, signs, close tolerance parts? If you cut artsy stuff you dont need to be as accurate therefore your table can be built cheaper and cut corners. I agree 100% with what DanOSBh and his suggestions. Good setup is stepper package from candcnc w/ thc(geared 4.5,5:1), simple waterbed, v-rail on one side, roller bearings on the other, rack/pinion xy axis, acme/ballscrew for your z, very light gantry for better acceleration and braking(alum.). This may help....

Hi, This is my first post here. I am gradually getting my workshop the way I want it and was looking to buy a plasma cnc table. The after checking with all the usual vendor options, I had to ask why are they so expensive? So I did some reading on building my own and arrived here many times. I just want a small 4x4 table and have looked at many build threads and they all seem to take a different approach. So, to make my research more focused, what is the best design on a 4x4 table? I plan on using Mach 3 and have all the computers I need, and I want THC for sure. How many available FREE plans are available so that I can download and evaluate them? I plan on buying a mill before I start the project and already have welders etc....
Thanks for your time,
G

If you are anything like me there isn't a set of plans out there I'd follow to the letter. If you change much of anything on a set of plans. You then are forced to do other work arounds as well. So if you are going to re-invent the wheel so to speak. Just as well start from scratch with borrowed designs from other factory level & home built modles.

Besided I don't personally know of more than a couple sets of table plans anyway.. 1 set is listed here in the build logs for free. Last time I was on ebay someone is selling plans for about $19.99 I think


If you'll take all your free time for a couple weeks & read I DID SAY READ NOT SKIM the build logs in both plasma tables, & router tables sections of CNC Zone You'll have a pretty good knowledge of what is involved & pretty good look at most design variables.

If you have the ability to build one of these tables. Not having a set of packaged plans shouldn't be a problem either.

NEIL

for electronics part i suggest you buy the complete kit from candcnc.com

for stepper and servo it depends on what your needs are.. the stepper works really well but doesnt have feedback so it doesnt know the actual exact postion.. incase the stepper motor gets jammed or miss step u might loose a little accuracy..

one of my machine is servo and other is stepper.. so far that stepper machine works perfect i havent had problem only time i had problem is when the machine required to pause and it lost the step so i homed it and that solved the problem..

cost of stepper/servo is big difference

for linear rail i suggest you use v bearing with v railing if i had to build whole thing again i would use that instead of pillow block open bearing that is currently on my machine..

for gearing part.. one of my machine is on chain drive and the accuracy is very good.. im happy with it..

the rack n pinion is a good way to set it up.. but for the cost factor chain is very cheap..

hope those info helps

Cheers
Dan

Dan,
Thanks. That is the kind of info I was after. I had already found the CandCNC site. I will want to put the machine on casters so I can roll it outside of the shop into the driveway to keep the dust down. I already know about the water table but have seen many pics of machines outside. They must be there for a reason.
:cheers:
Grumple

Well their are many different aspects to consider on a cnc build. First thing is what is your total budget on a 4x4 table. Also, when do you wanna have your machine up and running? This will help get you going in the right track. Some people spend 3 thousand dollars and others spend 12 thousand. If you have a very low budget you have to cut corners on your rails/material size/cnc package etc.... Some very cheap tables cut just as good as a very expensive table, all depends on your decision making on the design/materials. Second what is your objective of the parts you cut, artwork, signs, close tolerance parts? If you cut artsy stuff you dont need to be as accurate therefore your table can be built cheaper and cut corners. I agree 100% with what DanOSBh and his suggestions. Good setup is stepper package from candcnc w/ thc(geared 4.5,5:1), simple waterbed, v-rail on one side, roller bearings on the other, rack/pinion xy axis, acme/ballscrew for your z, very light gantry for better acceleration and braking(alum.). This may help....

Dustin,
I was thinking $5,000-$6,000 would do a fine machine. Some of the commercial ones look cheap although I am sure they work well. I will most likely use a PowerMax 45. I want THC for cutting thin stuff too. I would most likely want to do the artwork stuff along with 1/2 steel. Also 1/2" aluminum. I want it to be versatile. Mainly brackets and gussets etc... I want to use Mach 3 and Sheetcam. Good point on the gantry. I would have not thought a heavier steel gantry would slow it down. As long as its reasonably fast its good enough as its a home workshop and not high production.
Thanks,:)
Grumple

If you are anything like me there isn't a set of plans out there I'd follow to the letter. If you change much of anything on a set of plans. You then are forced to do other work arounds as well. So if you are going to re-invent the wheel so to speak. Just as well start from scratch with borrowed designs from other factory level & home built models.

Besided I don't personally know of more than a couple sets of table plans anyway.. 1 set is listed here in the build logs for free. Last time I was on ebay someone is selling plans for about $19.99 I think


If you'll take all your free time for a couple weeks & read I DID SAY READ NOT SKIM the build logs in both plasma tables, & router tables sections of CNC Zone You'll have a pretty good knowledge of what is involved & pretty good look at most design variables.

If you have the ability to build one of these tables. Not having a set of packaged plans shouldn't be a problem either.

NEIL

Neil,
I found those plans from MLaws and thats all I got to go with. They look like a great start. The questions a new builder like me have are sometimes really basic like, on a 4x4 table is it really 4x4 or and inch larger for clearance? Hate to find that out after its done. I have thoroughly read a lot of builds. Some of them leave you hanging where the OP says he will report back and never does. Others give you part of the plans but not all of the plans. I am a good reader. :cool: I need to read some in the CNC Router area though.
Thanks,
Grumple

One suggestion i have... try build a table with water bed.. the results are amazing.. at first i was expecting far less improvement from water bed and now only dust that comes out is steam which is nothing compared to before when i did test cuts without water bed holly cow the dust got everywhere and my whole shop is dirty fast

if u have waterbed u wouldnt even need to pull the machine outside to cut

i would build at least 2 inches larger than 4x4 so make it 50 inch by 50 inch

i would build at least 2 inches larger than 4x4 so make it 50 inch by 50 inch

Dan,
Thanks for the clearance answer. I know about water tables but they seem like they too would be messy. I guess I will leave that option open. can a water table be low capacity like 1 or 2" of water and still perform properly? I would hate to move the machine and slosh all the water on the floor.
Thanks,
Grumple

I's say that 2" is a minimum measurment on extra room. I guess it depends some on the material you are planning to cut. If it's all thinner material like gauge thickness materials less toom is needed because the material is easy to handle. Once you get into thicker material & have to use an overhead hoist or fork lift to handle material. Parts of your machine become much more vulnerable to being hit by swinging sheet metal.

The direction you gantry traveles along 2 of your table frame rails needs to be long enough to park your gantry completely clear of your cutting surface. I would expect to obtain a cutting surface of 4' X 4'. Your frame size will approach 5' X 6' outside dimentions. My 5' X 10' cutting surface is actually 6' 4" X 12' 4" outside dimentions.

Neil,
I found those plans from MLaws and thats all I got to go with. They look like a great start. The questions a new builder like me have are sometimes really basic like, on a 4x4 table is it really 4x4 or and inch larger for clearance? Hate to find that out after its done. I have thoroughly read a lot of builds. Some of them leave you hanging where the OP says he will report back and never does. Others give you part of the plans but not all of the plans. I am a good reader. :cool: I need to read some in the CNC Router area though.
Thanks,
Grumple

I'm sure the reason people don't follow up is mainly: (1) It takes lots of time to report progress, take, edit, crop, save & finally upload pictures. (2) Projects simply get scrapped or sold as the unplanned for money & time piles up.

I Used others knowlege when I began my build. Just like you are doing now. I decided quickly I'd try to give back once my build was operational. & I as well as lots of others continue to do so.

It's up to you to weed through all the information & pick the path that best suits your needs.

In the time it has taken to create 600+ posts I have done. I could have built another couple tables.

I can only imagine the countless hours Mlaws has in creating those plans for others to benefit from.

Does your $5,000 - $6,000 budget include the cutter as well or is that strictly for the table? IF that's just your table budget, then you're starting to encroach on the price of commercial tables like the PlasmaRoute Blaze (http://www.plasmaroutecnc.com/blaze.html). For a bit more you can get an ez-Router, which is the route that I went. I would have loved to build a table myself, but at the price that some of these companies are now offering tables, it was hard to justify it, especially since it would take weeks/months of my time to do the research and the build.

Does your $5,000 - $6,000 budget include the cutter as well or is that strictly for the table? IF that's just your table budget, then you're starting to encroach on the price of commercial tables like the PlasmaRoute Blaze (http://www.plasmaroutecnc.com/blaze.html). For a bit more you can get an ez-Router, which is the route that I went. I would have loved to build a table myself, but at the price that some of these companies are now offering tables, it was hard to justify it, especially since it would take weeks/months of my time to do the research and the build.

I was hoping that included the plasma torch and I think it easily can. Commercial stuff sometimes gets too proprietary for me and I don't like that when it comes to support and parts. The other good thing is I have plenty to keep me busy while I research and save the $$ for the project. That way I leave all options open until I have cash in hand. :banana:
Grumple

I's say that 2" is a minimum measurment on extra room. I guess it depends some on the material you are planning to cut. If it's all thinner material like gauge thickness materials less toom is needed because the material is easy to handle. Once you get into thicker material & have to use an overhead hoist or fork lift to handle material. Parts of your machine become much more vulnerable to being hit by swinging sheet metal.

The direction you gantry traveles along 2 of your table frame rails needs to be long enough to park your gantry completely clear of your cutting surface. I would expect to obtain a cutting surface of 4' X 4'. Your frame size will approach 5' X 6' outside dimentions. My 5' X 10' cutting surface is actually 6' 4" X 12' 4" outside dimentions.

Millman,
Thats good info. I thought about it after asking and realized the gantry needs to be out of the way and not in harms way when loading etc.
Thanks,
Grumple

Are you an expert on milling machines? I have a question on one if you are as I am going to buy one soon. :)

I'm sure the reason people don't follow up is mainly: (1) It takes lots of time to report progress, take, edit, crop, save & finally upload pictures. (2) Projects simply get scrapped or sold as the unplanned for money & time piles up.

I Used others knowlege when I began my build. Just like you are doing now. I decided quickly I'd try to give back once my build was operational. & I as well as lots of others continue to do so.

It's up to you to weed through all the information & pick the path that best suits your needs.

In the time it has taken to create 600+ posts I have done. I could have built another couple tables.

I can only imagine the countless hours Mlaws has in creating those plans for others to benefit from.

I fully understand that. I was just saying that after reading some threads they seem to be cliff hangers. I know its a lot of work and at first its fun and then other things happen along the way and sometimes the project ends because of lack of funds, lack of interest, divorce form spending to much time on the project etc... :argue: I appreciate all the help whether it dead ends or not as I can learn from that too.
:cheers:
Grumple

I was hoping that included the plasma torch and I think it easily can. Commercial stuff sometimes gets too proprietary for me and I don't like that when it comes to support and parts. The other good thing is I have plenty to keep me busy while I research and save the $$ for the project. That way I leave all options open until I have cash in hand. :banana:
Grumple

Yes, you can easily squeeze a plasma torch into that budget if you build this yourself and take the time to research it bottom to top. You're also right about the saving money aspect of it. If you're looking to purchase a brand new plasma unit, I would suggest getting it off of e-bay, like I did mine. Not only did the seller offer free shipping and a free auto-darkening welding helmet with my purchase, but I was able to take advantage of the Microsoft Live.com cashback program going on and I got 12% off the sale price. Instant $175 back in my pocket for doing nothing more than using Live.com to perform a search (and the required registration process). Unfortunately, I think the MS Live.com program is down to 8 or 9% at the moment, but it seems to change daily.

As far as milling machines go, I don't own one, but have years of experience on some large Bridgeport machines (not sure of the model). So if you have some questions, I can try to field them too. If not, just throw up a post in the appropriate mill section of this forum and you'll be sure to get an answer.

Hypertherm has a "trade in" offer on certain models going right now also. I just purchased a HT 1250 today. Best I remember the amount rebated back to me was just under $400.00 I would imagine the trade in allowance is less with smaller mod. machines.

"Trade in" is a bit deceptive as all I had to give was the make, mod, & ser.# I did not actually have to give up the old plasma. Not that I would have cared, It was a piece of pure junk anyway. I'm just glad I hadn't already went to the dumpster with it.

I don't call myself an expert at anything but sleeping. I have used & maintained Bridgeport type milling machines for many years. I have never had one to basket case, then put back together. if you havr that type of questions then I'm not your man. What to watch for when purchasing used, or operation of, I may be able to help.

Hypertherm has a "trade in" offer on certain models going right now also. I just purchased a HT 1250 today. Best I remember the amount rebated back to me was just under $400.00 I would imagine the trade in allowance is less with smaller mod. machines.

"Trade in" is a bit deceptive as all I had to give was the make, mod, & ser.# I did not actually have to give up the old plasma. Not that I would have cared, It was a piece of pure junk anyway. I'm just glad I hadn't already went to the dumpster with it.

I don't call myself an expert at anything but sleeping. I have used & maintained Bridgeport type milling machines for many years. I have never had one to basket case, then put back together. if you havr that type of questions then I'm not your man. What to watch for when purchasing used, or operation of, I may be able to help.

I just bought a PowerMax 30 as I needed portability so the next one will be for the table. As far as mill questions, I was going to buy the Grizzly here: http://grizzly.com/products/Horizontal-Vertical-Mill/G3617 unless someone can tell me a good reason not to. I don't like all the weight involved but heavy is good for machining. They have lots of smaller mill/drill type machines that may be plenty capable but thos one seems like a deal. I wonder why the free shipping as compared to some of their new product lines though. What do you think?
Thanks,
Grumple

I just bought a PowerMax 30 as I needed portability so the next one will be for the table. As far as mill questions, I was going to buy the Grizzly here: http://grizzly.com/products/Horizontal-Vertical-Mill/G3617 unless someone can tell me a good reason not to. I don't like all the weight involved and they have lots of smaller mill/drill type machines. What to you think?
Thanks,
Grumple

Grizzly is a well known brand/vendor around these parts and their machines are generally reviewed to be of great quality for the value. This mill looks to be about a similar size to the Bridgeport I was using for several years and I thought it was a great size to tackle almost any project that came my way. I could have very easily gotten away with a smaller unit and intend to do so in my current shop I am building up. My mill very well may come from Grizzly when I have the funds.

For the money it's probably a fair price. Especially for the Home Shop Guy. I just replaced the milling head on a 9 X 42 variable speed after 14 years of commercial shop use. (30-40 hrs per week) The machine base is still in great condition. The head was still running ok it was just beginning to get a bit noisy. I didn't have time for exploratory surgery, order parts & rebuild it. A new head was only $2100.00 shipped to the door.

My machine wasn't a Grizzley but was made by the same manufacturer in China, (Nantong)

I thought it seemed like a deal because of the horizontal axis. Don't know how much I need it but its not much more than the one without it. They have a new Shopfox as an option but being its new sometimes its better to wait until the reviews come in. Plus its not free shipping.
http://grizzly.com/products/Shop-Fox-Vertical-Mill-9-x-49-/T20828

Then of course there are all these others to sort through:
http://grizzly.com/products/mach-specs.aspx?key=480000

But I think the one I picked seems like a deal. Just want to be sure. :D

Thanks,
Grumple

Most usually all you'd ever need the horizontal axis for is a gear or splines. I have a larger knee type mill with a NT 40 taper horizontal spindle. I've had it set up for splines 1 time in the last 5 years.

On reviewing the specs of the mill you listed. The biggest issue for me is the vertical spindle will not run very slow. Most of my milling machine work is done at spindle speeds from 70-700. One of mine is a vari speed head range 60-4500 The other is a step pulley 16 speeds 75-3600 Second issue I don't see power feed on the vertical quill either. Almost a must for getting nice finish on holes you may need to bore. If you are limited to single phase power I'd much rather have this machine http://grizzly.com/products/Shop-Fox-Vertical-Mill-9-x-49-/T20828 wouldn't be surprised if they are not built in the same factory.

I'm sure the machine you listed is a far cut above the usual import table top mill/drill. The main reason it the weight you mentioned not wanting to deal with.

In the machine tool word MORE weight ALWAYS = more stability.

There are most usually many full size Bridgeport type mills with table size 9 X 42 & up for sale at or below that price range. The average 9 X 42 weighs in about the same. Then of course you need to know what to look for when buying used.

Lots of linear rails available for just your applications!

Round rails are considered best for plasma apps.

Stay away from steppers because everyone has a collision at some time.

Using a water tub with a good ventilator is best. Forget rolling outside unless you empty and then refill with water.

Good luck to you!

Jim

Stay away from steppers because everyone has a collision at some time.
Good luck to you!
Jim

Care to explain a bit farther???

I just this week watched a servo gantry run off then 1 side stop & the other keep going & destroy several dollars worth of hardware.

Most usually all you'd ever need the horizontal axis for is a gear or splines. I have a larger knee type mill with a NT 40 taper horizontal spindle. I've had it set up for splines 1 time in the last 5 years.

On reviewing the specs of the mill you listed. The biggest issue for me is the vertical spindle will not run very slow. Most of my milling machine work is done at spindle speeds from 70-700. One of mine is a vari speed head range 60-4500 The other is a step pulley 16 speeds 75-3600 Second issue I don't see power feed on the vertical quill either. Almost a must for getting nice finish on holes you may need to bore. If you are limited to single phase power I'd much rather have this machine http://grizzly.com/products/Shop-Fox-Vertical-Mill-9-x-49-/T20828 wouldn't be surprised if they are not built in the same factory.

I'm sure the machine you listed is a far cut above the usual import table top mill/drill. The main reason it the weight you mentioned not wanting to deal with.

In the machine tool word MORE weight ALWAYS = more stability.

There are most usually many full size Bridgeport type mills with table size 9 X 42 & up for sale at or below that price range. The average 9 X 42 weighs in about the same. Then of course you need to know what to look for when buying used.

millman52,
That is the other machine I had my eye on like I mentioned in the post. :) Great points too. That is why I asked so I can get the best capability for my $$. I know the more weight the better machine for stability etc and either way I will need a fork truck rental to move it as my cherry picker was looking shaky when I unloaded my sheer and I don't need to drop my new mill when I get it. I want new as like you said, I want it to be right.
Thanks,
Grumple

Lots of linear rails available for just your applications!

Round rails are considered best for plasma apps.

Stay away from steppers because everyone has a collision at some time.

Using a water tub with a good ventilator is best. Forget rolling outside unless you empty and then refill with water.

Good luck to you!

Jim

I think I am going rack and gear drive with a ball screw for the THC. I did some research and steppers seem fine but I have heard about crashes too. Draining and refilling seems like a pain but if I know that before I build I can definitely put a good drain system on it just in case.
Thanks,
Grumple

Lots of linear rails available for just your applications!

Round rails are considered best for plasma apps.

By whom?

I don't know anyone that considers round rails longer than about 36" to be best for anything. Plasma is more forgiving of flex and distortion because it's not a precision cutting process, but accuracy of a machine is the factor of ALL the errors added together. While it's true plasma is a dirty, nasty process and will foul any exposed surfaces any precision linear component is at risk. If you use the supported round rails and a partial wrap bearing (which will gain you the rigidity you need) you have basically the same structure as a standard square linear bearing.



Stay away from steppers because everyone has a collision at some time.


Huh? If you jam a stepper or hit a stop it just stalls....no harm no foul! It's not even required to have limits unless you just don't like the noise of stalled steppers (sounds bad but causes no damage)

The misunderstanding of how to properly gear and use steppers leads to the fear-mongering of lost steps and the incorrect blanket statements that servos are "better" than steppers. We sell and use (internally) both types of systems. We counsel the builders to match the usage to the type of drive and motors. Lighter gantries that are plasma only do not justify the added expense of servos. It's much like the argument of Gas VS Diesel engines. It all depends on what the end use is. There are distinct pros and cons for both types of systems.

It's Servos you have to be careful not to have a collision with. We put overload sensing on our servo power controls, so a stall will instantly shutdown power to all the motors. I have run my bigger servo based table into the stops (especially Z) accidentally several times. I have never damaged a motor, driver or anything on the table. With no power protection something will break or burn up.


Using a water tub with a good ventilator is best. Forget rolling outside unless you empty and then refill with water.

Good luck to you!

Jim
Now that I agree with.

Grumple, Are you going to design your table or just kinda wing it. If you need any design work, im more than glad to help. I specialize in autocad 3-D and could probably have your machine designed in less than 15 hours. Just make a parts list of everything you want to use... If your interested just post me back...

Grumple, Are you going to design your table or just kinda wing it. If you need any design work, im more than glad to help. I specialize in autocad 3-D and could probably have your machine designed in less than 15 hours. Just make a parts list of everything you want to use... If your interested just post me back...

Dustin,
How nice of you to offer your services for free :p I plan on doing it myself but I appreciate the offer. I have a few projects ahead of this that I need to finish while I get all the research on the plasma table. I plan ahead.:D
Cheers,
Grumple
:cheers: