Another First Router

[ger21]

Gerry,... That is one super table!! If I didn't have the steel to use, I would have copied YOUR table!

Thanks John. I'm pretty happy with the way it turned out. Now if I could only find time to finish it....

[Trainhound]

Gerry, how thick are the sides of your gantry? I noticed you're going with the xylotex 3 axis board, are you going with the complete kit in the box with the 30v supply or the non-boxed kit with the 24v supply? and how whill this effect performance?

[ger21]

I'll have to check, but I believe the sides are about 1-5/8". Two layers of 1/2" MDF with a 5/8" hardwood frame in between.

I have the old style Xylotex, a 3-axis + a single axis, with a 24V power supply. I'm not sure if the difference between 24V and 30V would be that much, but possibly up to 20% higher speed, best case. The Xylotex purchase was based mostly on cost. The HobbyCNC chopper wasn't available at the time, and Geckos were too much money for this project.

[Trainhound]

Gerry, may gantry is set up just like yours torsion box design, but I was trying to figure out how to attach my y torsion box to the gantry sides. I use 2" square tubing for my rail rather than pipe. I just don't know whether I should bolt & glue to the side or just bolt it in case I need to make changes to the Z axis, how are you connecting the Y torsion sides to the gantry side? I was going to follow your recommendation on using 1 piece panels with a hole in the middle to close up the sides of the Z. Would just using 4 bolt on each side keep the bridge from flexing?

Ed.

[ger21]

My gantry sides will have pockets to accept the Y-axis tubes. The box itself will be shimmed as needed to keep the sides parallel, and then screwed through the sides. I don't plan on having any adjustment, because My template for the sides was CNC routed, so the pockets will be perfectly perpendicular to the X-axis tubes. I wouldn't use glue, that's asking for trouble.

I don't exactly follow what you mean by using 4 bolts, but I'm pretty sure it needs to be completely boxed in to eliminate flex.

[ger21]

I got a new camera yesterday, with video.

Here's a few pics of what I've been doing. The gantry sides are ready for paint (tomorrow). They were lightweight MDF, and very soft, so they've been coated with West System Epoxy to both seal them, and make them a little tougher. Where the bearing angle will be mounted, the 2 slots at the bottom, I epoxied some aluminum strips into some routed slots so when I tighten the angle down, it won't crush the MDF. The Baltic Birch ply piece at the bottom will be drilled for the threaded rod to go through, tying the 2 sides together, and the leadscrew nuts will mount to the bottom of it.

I also started making some leadscrew mounts, using 1/2" phenolic plate and rollerblade bearings. I cut the plate in 3"x3" squares, and, using a 22mm forstner bit (made by CMT if you need to find one), I drilled about 3/16" into the center, followed by a 1/2" hole all the way through. I then epoxied 2 back to back, using the bearings and an 8mm bolt to pull them together and make sure they spun freely before the epoxy set. Once cured, I trimmed them square on my table saw, and now just need to drill the mounting holes. These should be plenty stong, and a little easier to work with than aluminum.

I also weighed some parts, and it looks like I've substantially overbuilt.
The gantry sides are about 8 1/2 lbs each, and the gantry torsion box is about 22 lbs. That's 40lbs, + 8 lbs for the router, and probably another 20-25lbs for the Z-axis, screws and steppers. Somewhere around 75lbs probably. I think I was originally thinking somewhere around 50, but it adds up fast.
But, as I've mentioned before, The table deflects very little with over 200lbs on it, so I don't see any problems, except maybe for the load the bearings put on the pipe. I've got an idea to possibly add more bearings on top to help carry the load, but I'll wait to see how it works out.

So, if all goes as planned, and I get everything painted tomorrow, I plan on assembling the gantry on to the table in the next week or two. I'll be making the X axis bearings and mounts today and tomorrow, so when the paint dries (hammer paint can be tacky for a few days) I'll be ready to go.

[spalm]

I was wondering if you could share how you are going to attach your leadscrew nuts to your gantry walls. Some kind of bracket or block, I ‘spose.

Steve

[ger21]

You mean the driven nuts? Oh, at the bottom of the sides, right? I was going thinking of buying some 2x2 (whatever size will work) aluminum angle and mount the nuts to that, and mount the angle to that plywood "wing" on the bottom of each side.

I did the final assembly of the table to the base last night, and provided the bearings I bought on Ebay arrive today or tomorrow, I'll get the gantry mounted and rolling this weekend. No leadscrews yet, though. Then I'll start making the necessary changes to the Z-axis.

[ger21]

Finally got something that actually moves, although not by itself yet. Still have to install the threaded rods under the table to pull the bearings tight to the tubes.

[ger21]

Here's some better pics of the bearing mounts. 1/4" thick 1-1/4" angle. The spacers were cut from 1/4" brass pipe on the table saw (careful if you try this) and the length adjusted on the disk sander. Somehow I cut most of them within .005 of each other. The notch in the top of the angle was done on a router table. I cut a 45° dado in a piece of plywood, to hold the angle with the point down. Then just slid it along the fence on the router table. Go very slow, as the bit will want to pull the aluminum into it.

[Mr.Chips]

You have a very nice looking machine there. Glad to see your progress.

Hager

[CNCRob]

Congrats on the progress Gerry, Its looking great.

[Trainhound]

Nice machine Gerry!

[Madclicker]

How wide is the base of the gantry uprights and how did you decide on this?

[Pat2000]

How do you folks keep the wood dust/chips off the Skate bearings? will you fit covers? do you need wipers? or can you 'get away with' some dust n chips?

[Jason Marsha]

Very Impressive looking machine, congrats Gerry. Do we see plans for sale?

Jason

[Sanghera]

What do you use to adjust and tension your rails?
Thanks.

[ger21]

How wide is the base of the gantry uprights and how did you decide on this?

12" wide. I just guessed at 12" as a compromise between travel and stability.

The wider the better, but at the expense of travel. The rails are about 59 1/2" long, and leaving a little clearance on each end will give me about 45" of travel.

[ger21]

How do you folks keep the wood dust/chips off the Skate bearings? will you fit covers? do you need wipers? or can you 'get away with' some dust n chips?

This is a big concern for me. When the thing is finally running, I'm going to see if I can make some delrin covers that hold a felt wiper over the bearings. We have a large saw at work that uses a system like this. The felt is saturated with oil, which gives you an oiled surface for the bearings to ride on, while wiping the dust out of the way.

[ger21]

Very Impressive looking machine, congrats Gerry. Do we see plans for sale?

Jason

No plans for this one. I think I'm pushing the envelope for size of a wooden machine using basic construction techniques. Building the torsion boxes required precisely cut parts to keep the rails perfectly straight, and you'd need a 5 ft router to cut them. This is an untested design, and I'm finding a few issues as I go. The Z-axis needs additional support, and if it wasn't 90% complete, I'd have completely redesigned it. And while the round pipe seems adequate, I'm not completely happy with it. I may add 2 more bearings to the gantry sides to help carry all the weight. I think having the bearings running on steel angle is a better way to go, but I'm not sure if anyone pulled it off yet. See the open source hardware store thread for more on that. Also, my drawings only covered the gantry and table, from here on out I'm making it up as I go. I think when complete it will work at least as good as a JGRO machine, most likely quite a bit better, but to sell plans for it would require a complete redesign, and it would cost a lot more to build then. At some point in the future the machine will probably be for sale, but probably 2-3 years from now. I already have a lot of parts for it's replacement.

I am (slowly) working on some plans for a smaller machine (24x30), which I'd like to sell plans for, but also would like to sell precut kits, and some prefabricated parts like the torsion boxes. It may be a while though, as I can't seem to get all the other things done that I need to do to give me the time foor that.