Rigid Steel Router - 20" x 30"

[the_hamturdler]

Hey guys, just wanted to get some of your thoughts on my build, what to improve and what not. The main objective with my build is portability and rigidity, which don't always go hand in hand but I think I've found a good balance.

The machine will be made of 6 parts that will be bolted together via 1/4" thick hot rolled plates. This allows me to load the machine in a moving truck if needed without needing a forklift (the thing weighs 600 lbs without tube fill). Between the mounting plates will be an epoxy injection (much like Stefan Gotteswinter's epoxy tramming video). This give's me a perfect registration surface so that the machine can be assembled and disassembled and maintain accuracy. After leveling the machine, I will pour the epoxy rail beds so that the x and y axis are perfectly trammed in. Z axis will have epoxy rail beds as well.

All parts will be machining free, hence the epoxy. Instead, the steel parts will be laser cut and welded.

Specs!

X AXIS:
- 5 x 7 x 3/8" A500 steel tube @ 40" long
- 32" travel
- 2 x Hiwin 20mm profile rails mounted at 90* for epoxy leveling and strength
- 1605 ballscrew with 2:1 pulley for better speeds

Y AXIS:
- 2 x 3 x 3/8" A500 steel tube @36" long
- 22" travel
- 2 x Hiwin 20mm profile rails w/ epoxy leveling beds
- 2 x 1605 ballscrews with 2:1 pulleys

Z AXIS:
- 1/2" Hot rolled plate, laser cut to +-.01" (good enough for welding, that's what the epoxy is for)
- 2 x 20mm Hiwin profile rails
- 6.5" travel
- Hitachi M12vc w/ parts to upgrade to 2.2kw spindle eventually

Table:
- 20 x 30 x 5/8" Mic-6 tooling plate
- drilled and tapped grid 2" between centers
- drilled and reamed for dowel pins (eventually...)

Frame:
- 4 x 6 x 1/4" base tube
- 4 x 4 x 1/4" support tube

Electronics:
- Gradus M1 GRBL controller ( will upgrade to ess and geckos eventually)
- 4 x 300 oz-in steppers
- 48v power supply
- Inductive prox sensors

The tubes will be filled with something removeable until my housing situation is more permanents (possibly oiled sand, let me know if you guys have any ideas). Eventually I will go with epoxy granite fill but the cost and weight is a bit too much right now. Let me know if you guys have any suggestions on how to improve the design, thanks!

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[fretman_2]

Looks beefy!!!! Ought to be a heavy machine!

[ger21]

How do you get the epoxy on the gantry aligned on two different planes that are 90° to each other?

[the_hamturdler]

How do you get the epoxy on the gantry aligned on two different planes that are 90° to each other?

The top rail of the x axis will be poured along with the y axis beds so they are coplanar. The other x axis rail will either be shimmed traditionally or poured with the help of a machinist level so that its relatively close. I'm assuming the beam will have a good amount of twist and bow to it so more than likely it will be traditionally shimmed. To get the rail perpendicular I think I'll buy a webbed cast iron angle plate and run it with a dial indicator. If you have any tips for alignment, I'd love the help.

[pippin88]

Looks good.

You can usually do fine with a single ball screw and motor for a moving table.

[the_hamturdler]

Looks good.

You can usually do fine with a single ball screw and motor for a moving table.

Thanks. I went with double ballscrews simply because I already have the motors for a dual y setup and the cost of an extra ballscrews is pretty trivial. It also makes mounting easier, one less component to get aligned since they are just bracketed to the y axis rails. I'm a bit worried about racking, but haven't encountered it with my current router so I figured I'd try it.

[wizard]

First i must say you have some very nicce illustrations attached!

Hey guys, just wanted to get some of your thoughts on my build, what to improve and what not. The main objective with my build is portability and rigidity, which don't always go hand in hand but I think I've found a good balance.

Yes the two demands contlct considerably. Dont forget everything you add to an axis increases its weight. On a rlated note a few years ago i welded up a steel frame for a bench, the thing got heavier each time i wekded domething to it, by the time i was done rolling the frame over was a real challenge. So what im saying is dont add anything not absoluteky needed to a frame you expect to knock down and transport.

The machine will be made of 6 parts that will be bolted together via 1/4" thick hot rolled plates. This allows me to load the machine in a moving truck if needed without needing a forklift (the thing weighs 600 lbs without tube fill). Between the mounting plates will be an epoxy injection (much like Stefan Gotteswinter's epoxy tramming video). This give's me a perfect registration surface so that the machine can be assembled and disassembled and maintain accuracy. After leveling the machine, I will pour the epoxy rail beds so that the x and y axis are perfectly trammed in. Z axis will have epoxy rail beds as well.

You might be going over board with the Epoxy. For example you can buy steel plate, from a steel plate processor, fairly cheap ground flat and parallel. The llong axis are a bit more of a problem but id research the real expense of Epixy against the cost of machine work.

All parts will be machining free, hence the epoxy. Instead, the steel parts will be laser cut and welded.

Im not sure wha the point of being machining free is! You need to balance the cost of machining against the cost of Epoxy leveling. It seems like you are dismissing machining out of hand.

Specs!

X AXIS:

From the pics im assuming this is the Y axis if you start from the bottom and work up.

- 5 x 7 x 3/8" A500 steel tube @ 40" long
- 32" travel
- 2 x Hiwin 20mm profile rails mounted at 90* for epoxy leveling and strength

The mounting at 90 degrees will do nothing for you but create grief. If you want to minimize machining id most certainly would have the linear rails mounted in the same plane. Beyound that your extra complication adds weight and might actually weaken the Z axis.

In other words if you hoal is to minimize machining simplyfy the axis as much as possible. This also applies to axis weight control.

- 1605 ballscrew with 2:1 pulley for better speeds

You have the start of a nice rigid machine able to do accurate work so why the need for speed? This isnt a big problem because motirs and pulleys are easily changed after the fact. Generally i prefer timing belt driven leadscrews but that is more for inertia matching rather than speeds.

Y AXIS:
- 2 x 3 x 3/8" A500 steel tube @36" long

Maybe just a bit thin for an axis considering how beefy the rest of the machine is.

- 22" travel
- 2 x Hiwin 20mm profile rails w/ epoxy leveling beds
- 2 x 1605 ballscrews with 2:1 pulleys

Z AXIS:
- 1/2" Hot rolled plate, laser cut to +-.01" (good enough for welding, that's what the epoxy is for)

This just bothers me. First that you are welding to this plate and second that you are going to try to Epoxy level it. Probably third is that the plate is a bit thin.

As for the thinness remember the plate at points is unsupportted id go slightly thicker for better support.

As for welding i wouldnt do it unless your goal is to turn the plate into a C shaped channel for additional rigidity even here you would need post welding stress relief and machining. It is fairly easy to buy plates machined for your needs.

As for trying to Epoxy level this well good luck with that and your original design. I just see a massive challenge in getting all the surfaces in the right orientation.

- 2 x 20mm Hiwin profile rails
- 6.5" travel
- Hitachi M12vc w/ parts to upgrade to 2.2kw spindle eventually

Table:
- 20 x 30 x 5/8" Mic-6 tooling plate

That might be just a bit thin.

- drilled and tapped grid 2" between centers
- drilled and reamed for dowel pins (eventually...)

Frame:
- 4 x 6 x 1/4" base tube
- 4 x 4 x 1/4" support tube

That is a pretty heavy frame compared to the X acis members which are 2x3.

Electronics:
- Gradus M1 GRBL controller ( will upgrade to ess and geckos eventually)
- 4 x 300 oz-in steppers
- 48v power supply
- Inductive prox sensors

Your drives, power supply and steppers, must all be sized to work best together. In other words you are jumping the gun to suggest a 48 volt power supply.

The tubes will be filled with something removeable until my housing situation is more permanents (possibly oiled sand, let me know if you guys have any ideas).

Intitially do nothing. You frame is well designed for the most part, keep it light until a good resting place is found. There is also the issue of welding plates on the tube ends that interfers with filling the tubes. You want the tube ends capped to prevent parallelogramming of the tubes, you might even want internal stiffners, these would need to be designed to allow filling the tubes.

Eventually I will go with epoxy granite fill but the cost and weight is a bit too much right now. Let me know if you guys have any suggestions on how to improve the design, thanks!

The basic concept you have is pretty good. Ive mentioned some issues above, eye especially dont like the Y axis linerar bearing arraingement and the Z axis saddle as i just see more alighment and weight problems for no pay off.

You can buy pre ground plate steel fairly cheap. Your big distributors carry stock and you can order materials from specialist shops like Nifty Bar. If you dont have access to a machine shop id suggest this approach.

You illustrations are great but im perplexed by some of the gusseting on a machine where you are trying to control weight. Dont get me wrong gussets are very important but you dont want to over do it on a machine where weight is such a big issue.

Welding distorts and less than precise fit ups leads to more significant distortion. I say this because you mention laser cutting as being good enough for weld ups. Frankly when welding up machine tool components we will machine the parts to tight fit ups. Even then post weld up machining is often required. The goal is to minimize stress and distortion in the final piece. This isnt like fabrication work wher pieces are clamp together in the hopes that nothing distorts in the final assembly.

So what is all this noise about weld ups and laser cutouts about? It is just the suggestion that you dont assume anything about being good enough. Ive taken a 4.5" grinder and then a hand file to steel tubing that was band saw cut to make sure the tube was as square as possible. Before welding to it. It makes a huge difference if you dont have access to machine shop tools for post welding adjustment.

Factor in a decent cabinet for the electrical controls. This adds weight but well designed can secure your conttols during shipment. Plus the protection a good sealed cabinet offers during operation.

There is a real challenge to manging weight while keeping the machine easily transportable. On suggest is a bit cave man but consider designing in wheels. Either permanent brackets or easily bolted on for each sub assembly. With a little thought most parts can be moved wheel barrel stule or two wheel balanced style. This appoach is a lot safer than trying to strap parts to a cart or hand truck. You still want to keep weights managable for stairs and such. Also think big wheels here like a wheel barrel. The cost isnt huge and the piece of mind is a big win. Store the parts for wheeling around under the frame.

Prefer desing elements that enhace you ability too tear down and transport. For example after final assmbly and alignment add at least two dowel pins per joint. Make sure the dowel pins are threaded for easy extraction. Buy or make covers for the linear bearings to protect them during shipment. The more thought that you put into intial design to support breakdown for shipment the fewer problems you will have at reassembly.

I've rambled on here but for the most part you are off to a good start here.

[the_hamturdler]

Whew that's a lot of good critique, thank you Wizard!

I'm not too worried about the weight of the machine in general, in fact the heavier the better. So long as the machine can be broken into parts that can be handled easily, sub 200 lbs or so, it should be fine. The machine just needs to be able to load into a traditional moving truck. I had originally thought use wheels but I felt that pushing a 600+ lbs machine up a loading ramp would be pretty difficult. I'm not sure however...

I have not ruled out machining entirely, in fact we might be getting access to a cheap chinese mill at work soon (I think a Rong-Fu 31 / G0705 clone) that I will use if I can. Even then, I'm not too confident in being able to keep things accurate over the length of a 40" long beam. I will definitely be doing machining on the Z axis if the opportunity arises. The primary reason I have decided to use epoxy is because of the accuracy you can get for relatively low cost compared to machining. Especially in my area of California where shop prices are pretty steep.

The linear bearing arrangement on the x axis was inspired by the necessity to align the x and y axis using the epoxy. They would be poured at the same time to keep things coplanar. After hardening, the x axis rails would be mounted and then the y axis with the help of an indicator and an angle plate. If I want the linear rails to be on the same face of the beam the epoxy would have to be poured seperately and then the beam would need to be shimmed in place. It is certainly more difficult, but now that I think about it I could just mount the z axis and use it to sweep against an angle plate sitting on the table to get it trammed in. Not sure, I'll definitely give it some thought though.

The x axis rails are pretty small compared to the rest of the machine. I had assumed that most of the cutting forces experienced during cutting are radial (to the cutter) and not axial, thus having a beefy x axis wasn't so important. So long as the beams didn't deflect considerably from their own weight or the weight of the table they would be adequate. Is my theory incorrect? I was able to find some articles online about cutting forces, but couldn't find anything pertaining to axial cutting forces. I definitely think the table could be thicker. I considered making a tubular frame for the table to sit on but I was worried the weight would make my accelerations even slower.

All my presumptions for the electronics are based on what I already have laying around that will be reused for this project (the 48v power supply)

I really like the idea of using some dowel pins for the joints. I'm not sure how I could accurately drill and ream those holes without a mag drill, though. Have any ideas?

[wizard]

Whew that's a lot of good critique, thank you Wizard!

I'm not too worried about the weight of the machine in general, in fact the heavier the better. So long as the machine can be broken into parts that can be handled easily, sub 200 lbs or so, it should be fine. The machine just needs to be able to load into a traditional moving truck. I had originally thought use wheels but I felt that pushing a 600+ lbs machine up a loading ramp would be pretty difficult. I'm not sure however...

The idea with the wheels is to design those subassemblies so that they can be wheeled around. You certainly don't want to wheel around the entire machine

As side note I have a lot of woodworking machines in my cellar shop and each one of those I moved into the shop myself, some a couple of decades ago. AT my age I'm pretty sure I won't be moving them out of the cellar alone and even with help it would be a horrendous chore. If you intend to move house more than a couple of times do consider how your body will age. 200 point subassemblies are manageable today but maybe not so manageable a few years from now.

Consider for example the gantry beam, on a moving table weight isn't a problem so you can create a nice stiff gantry with a large beam. That is good but moving it around will be a chore and a risk to your health. Bolt a set of wheels to is so that you can move it around wheel barrow style and you can save a lot of strain.

I have not ruled out machining entirely, in fact we might be getting access to a cheap chinese mill at work soon (I think a Rong-Fu 31 / G0705 clone) that I will use if I can. Even then, I'm not too confident in being able to keep things accurate over the length of a 40" long beam.

That would be extremely hard to do and frankly I wouldn't recommend trying to do something so long on such a small mill.

I will definitely be doing machining on the Z axis if the opportunity arises. The primary reason I have decided to use epoxy is because of the accuracy you can get for relatively low cost compared to machining. Especially in my area of California where shop prices are pretty steep.

You might look about for hobbiests, steam engine fans and others that are conversant with machining and might have access to the right tools. Also there are maker spaces to consider.

You do need to consider that even if you buy pre ground stock you still need to consider how you will drill the holes to mount stuff and keep things orthogonal. A drill press might be a minimal requirement but the problem here is that you need one that is stiff enough to allow precision work. This just drives up your expenses if you don't already have one.

The linear bearing arrangement on the x axis was inspired by the necessity to align the x and y axis using the epoxy. They would be poured at the same time to keep things coplanar. After hardening, the x axis rails would be mounted and then the y axis with the help of an indicator and an angle plate. If I want the linear rails to be on the same face of the beam the epoxy would have to be poured seperately and then the beam would need to be shimmed in place. It is certainly more difficult,

I'm not sure I follow what you are describing here. I really don't see where the extra difficulty comes from. The approach that I like is to create a solid gantry design with rigid uprights and then assemble the machine and grout (epoxy grouts) the uprights in place once everything is aligned correctly. This is fairly common in commercial machinery. Devitt Machinery Company | Devitt Machinery Company is a company with a long history of selling material for grouting and replication. Much of what Moglice has is for sliding surfaces or if you will plain bearings. For much of what you want to do other epoxy suppliers can be had. I just linked Moglice to show you the various ways such materials can be used.

but now that I think about it I could just mount the z axis and use it to sweep against an angle plate sitting on the table to get it trammed in. Not sure, I'll definitely give it some thought though.

Personally I would tend to want to adjust the whole beam assuming the Z axis is square with the gantry linear axis.

The x axis rails are pretty small compared to the rest of the machine. I had assumed that most of the cutting forces experienced during cutting are radial (to the cutter) and not axial, thus having a beefy x axis wasn't so important. So long as the beams didn't deflect considerably from their own weight or the weight of the table they would be adequate. Is my theory incorrect? I was able to find some articles online about cutting forces, but couldn't find anything pertaining to axial cutting forces. I definitely think the table could be thicker. I considered making a tubular frame for the table to sit on but I was worried the weight would make my accelerations even slower.

I just realized I don't know what your intended usage is. There are many factors here from the weight on the table to the rigidity of the stand. Lets just say they looked out of proportion. A little extra bracing from one side to theater would help greatly.

All my presumptions for the electronics are based on what I already have laying around that will be reused for this project (the 48v power supply)

Used and free is always good.

I really like the idea of using some dowel pins for the joints. I'm not sure how I could accurately drill and ream those holes without a mag drill, though. Have any ideas?

The accuracy is achieved prior to the dowel pin installation. Think of dowel pins as nails that hold a structure in alignment. That might be a bit crude for some people but sometimes you need the security of a pin even if you can't do the fancy machining to bore a hole 100% perfectly square.