Reply with QuoteOh I remembered one! Should the tool be designed to end up in between the bearings for the x axis? T
Does that make sense?
I mean, should the router head be positioned in between the two x axis bearings?
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Some progress on my 30"x30" steel build.
So this is my design so far, I made up the picture above to give to my welder co-worker. This is a steel build that has borrowed heavily from 2rdesigns machine. I already have the 20mm rails, 1605 ballscrews, and most of the steel.
I got all the linear components from eBay, and am getting most of the steel from the shop at work. They have the 3x3 steel tube and the 6x2 steel channel. We have a band saw that makes fairly accurate cuts as well as grinders/welders, drill press etc.
I am kind of at a loss on how to design the gantry and how to make the machine easily tram able and adjustable. The pieces under the rails are aluminum and will attach directly to the rails. The rails and aluminum will than bolt to the channel through holes drilled slightly larger than the bolts to allow the rail to be adjusted for squareness.
Am I mistaken for sandwiching .25" pieces of aluminum between the steel and bearings under the assumption that it is generally flatter and truer than steel?
I still need to design the arms that will attach the gantry to the ball nuts for the X axis. I want them similar too this... I bring you my inspiration! Thank you for letting me plagiarize your build 2rdesigns!
I also need to come up with an adjustable Mount for the steppers. I think the bearings holding the ballscrews could have the holes drilled in the channel slightly larger to allow for vertical adjustment. Shims under the bearing blocks could be used for horizontal adjustment. I think a thin piece of steel welded to the side of the channel with a hole big enough for the shaft/coupler to pass through would work. Than maybe drill/tap 4 holes for some standoffs or threaded rod to hold the motor to the mount. I like the threaded rod because then the motor could easily be adjusted by screwing them in or out to get the shaft to match the screw.
I plan on using the cncrouterparts g540 with 320oz low Inductance motors.
I had more questions... I'll update when I remember them.
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Oh I remembered one! Should the tool be designed to end up in between the bearings for the x axis? T
Does that make sense?
I mean, should the router head be positioned in between the two x axis bearings?
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Last edited by Nipels; 03-21-2013 at 10:22 AM.
Bump... no thoughts?
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Bump
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I don't think you need to bump threads here. For the most part people here are very professional in thier conduct and would provide an answer if they felt they could contribute.Originally Posted by Nipels
So no one can answer my questions after a month of waiting? Guess I'll start anew thread from now on.
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I don't think its the bit that needs to be centered but the gantry as a whole. So, your beam, z-axis, spindle (weight/center of gravity) centered between the bearings. Otherwise the gantry will want to tip in one direction or another then adding cutting forces to the mix in that same direction.
But, if its built ridged enough and your close to center I don't think it makes a whole hell of a lot a difference. I have seen plenty of machines on here that cant be balanced perfectly at all.
btw.. I also like 2rd's machine and will be stealing many cues from it..
Last edited by SixOfOne; 04-10-2013 at 01:34 PM. Reason: added a thought
I don't perceive that Al will be any flatter than steel for a given material type, but in general it is better to not have too many different types of metals touching each other, or it can accelerate corrosion. For a near perfect surface, you can use ground plate, but it isn't cheap.
One way to level areas is of course to use self leveling epoxy. The other is to use some shims, for example under the ends of the gantry. For tramming, there is a thread by jharvey that shows a nice tram adjust setup toward the end of his build thread.
I think one reason your post is not getting as much activity as you like perhaps, is that the forum has gone through a lot of changes in the past month, and we are all still getting used to them, so it throws us off a bit.
Steel channel can be deceptive about just how stiff it really is. Sometimes it works out, and sometimes the web flexes a lot more than people expect. Tube is surprisingly better, but since you have the steel already, maybe just continue. If you can obtain tube steel in that rough size easily, I would change it out now.
As far as how to located the bearing blocks relative to the router bit, consider sticking out your arm straight ahead and pretending that this is the distance from the center line of the bearing block, to the center line of the bit. Now, pick up a 10 lb weight of some kind, and hold it out there straight out. Now, have someone push up and down on your hand while you try to hold the weight straight out there.
This is what is going on in a router setup, only the forces are larger. From this, you can estimate the location of the bearings relative to the bit, and also see that the answer is not so simple to answer, but rather is a bit specific to the build. It helps if the bearing blocks are fairly long, as this helps with the lever arm effect.
Any progress?
I'm still waiting on my C-channel to arrive. My local supplier ordered what I told him but his supplier sent the wrong size.. I hope it will be here Monday.
Sorry I thought this thread was dead. I got frustrated and stopped checking.
A lot of progress on getting materials. I have both pieces of channel cut to size. I have cut 2" x 6" pieces of 3/8" steel to use as the bearing mounts for all 6 sets of bearings. I have been trying to find a suitable piece of steel for the gantry at work but nothing yet. I was considering using another piece of the 6" x 2" channel but may try out a 2" x 2" piece of square tubing with 1/4" wall. It seems kind of small though.
I setup a gauge at work to measure deflection in the center of a 46" piece of the tubing suspended between two cinder blocks. I couldn't get a reading after standing on the center. I figured the sbr20 rails would only add to the rigidity. Any thoughts on the channel or tube?
I have made no progress on the 3d model as my 30 day trial is up. I plan on buying as soon as I'm settled back in from a month away traveling for work.
What kind of screws go into the sbr20 bearing blocks? I plan on using the same screws to attach the rails to the steel.
Anyone have a source for wedge shims? The channel I have has a taper where the nuts/bolts will have to be tightened.
Thanks for your help guys. I'll take pics and post them asap. I'll check back a lot more often now that my questions are being answered.
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About the channel. I am thinking about welding supports at the tips straight up and down. This would allow the screws to continue to be recessed in the U shape they make and add extra resistance. The channel is thick structural steel used on some of our rigs with 1/2" wall at the bottom of the U. I'll hold off to see how it performs before making potentially unnecessary welds.
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For my gantry beam I went with a piece of 3060 from 80/20 (the Base 30 from Mitsumi has a 30mm t-slot space, which would have been easier to work with, but 4 less tap-able holes on the ends and it was a little more money) mine will be about 68" long. I went with the 80/20 for a few reasons.Sorry I thought this thread was dead. I got frustrated and stopped checking.
A lot of progress on getting materials. I have both pieces of channel cut to size. I have cut 2" x 6" pieces of 3/8" steel to use as the bearing mounts for all 6 sets of bearings. I have been trying to find a suitable piece of steel for the gantry at work but nothing yet. I was considering using another piece of the 6" x 2" channel but may try out a 2" x 2" piece of square tubing with 1/4" wall. It seems kind of small though.
I setup a gauge at work to measure deflection in the center of a 46" piece of the tubing suspended between two cinder blocks. I couldn't get a reading after standing on the center. I figured the sbr20 rails would only add to the rigidity. Any thoughts on the channel or tube?
I have made no progress on the 3d model as my 30 day trial is up. I plan on buying as soon as I'm settled back in from a month away traveling for work.
What kind of screws go into the sbr20 bearing blocks? I plan on using the same screws to attach the rails to the steel.
Anyone have a source for wedge shims? The channel I have has a taper where the nuts/bolts will have to be tightened.
Thanks for your help guys. I'll take pics and post them asap. I'll check back a lot more often now that my questions are being answered.
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-Light-er weight (maybe smaller motors)
-Easier Mounting, just tap the end holes and just bolt right to my side plates. (with the steel I would have to make threaded blank inside the tube, big PITA)
-Better bolting options in general (Gantry bearing plates right into the t-slots)
-More then 95% of the machine is rust proof (Florida humidity, Liquid Sunshine)
My sbr's from Glacern have 5.5mm holes so I ordered 5mm socket caps and 5mm tnuts. For you to mount them to steel just the cap screws and alllllot of tapping.
My aluminum channel has the same taper where I need to bolt it down.. I still havent worked out that bit yet, maybe you will get there before me and I can steal your idea, lol..
Steel is 3 times stiffer than aluminum. Fun fact.
I need to know which size screws the bearings take, not rails. My rail holes weren't pre drilled.
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They should be M6 x 1.0
How close should the holes in the aluminum part of the rail be drilled together? 6"?
I'm grabbing the hardware today and beginning to drill.
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Wedge shims seems to be the way to go. If I find the perfect ones I'll let you know.
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6" should be fine..
My rails came drilled with 5.5mm holes. The holes are spaced 15cm apart which is just under 6".
I started drilling yesterday . It was rough at first with my tiny drill press but I got most of the holes drilled for the rails and the channel. I plan on tapping the channel and redrilling the holes in the rails to be a little bit bigger than the bolts that hold them so I can easily make small adjustments in alignment.
I'll post pictures later today.
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Hows it going Nipels? Waiting on orders and stuff is killing my progress..
I've been working out of town for the last few weeks so progress is slow. I'm going to grab the 3x3" steel tube next. .25" wall should be enough for the gantry and cross members underneath the channel. I have pictures but I'm posting from my phone so I don't know if I'll have time to post them later.
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