[skyguynca]

I finally got around to posting some pics of my build.

Day one and two I did all the wood work, cut, fitted, epoxied and painted. I wasn't looking for pretty, just functional but it turned out fine. I did use industrial MDF instead of plywood, so we will see how it holds up. I also made a change and made both left and right the same. I may put another stepper motor on the opposite site to even out the movement and eliminate a possible chance of racking.

Day three I made the x plates, angles and rails.

David.

[skyguynca]

Last night after posting pictures, I had some time so I headed to the garage and drilled the cold rolled steel rails and tapped them for the 1/4-28 bolts. Then I cut two 3/4x3/4x.125 aluminum angles for 24.125 in to place between the rails because that will be the finished dimensions inside the rails.

I put everything in place, measured from the base up to the bottom of the rails, no spacers needed. Put the dimension jigs in the rails, then measured diagonally to make the rails square and parallel at the same time. Marked the base and started drilling pilot holes for the lag bolts.

Now I attached the rails to the angles on the table top so I could be sure the bottoms were flush. Then I mounted the assy on the base. Again put my distance jigs in place, measured diagonally and got it square and parallel again.

To just make sure I used my smart level and checked the base, the verticals, across the rails and along the rails, every thing checked out square and level.

The build is going good so far. If I get some time after work Friday afternoon I will start making the parts for the gantry.

David

[skyguynca]

I think there are only the router mounts and a couple of limit switch brackets and the Z rail left to cut. I broke out the miter saw, changed the blade and went to town cutting the aluminum parts. Cut them all with a 1/32 to 1/16 oversize for filing down.

David

[skyguynca]

Well worked a few hours today on the parts. I made parts 1 thru 6. My drill press motor fryed so I lost a couple of hours running out and getting a new drill press. The cheapest motor was $99 and a 5 speed drill press was $70. Well that was a no brainer. I am keeping the old one and if I come across a motor cheap then I will have two.

The tapping took the longest time, steel is so much easier than aluminum.

[GTFreeFlyer]

You are very fast or have lots of free time
I found tapping in alum to be easier and quicker than steel.

[momus_cnc]

Beautiful build, and definitely coming along quickly. Just out of curiosity, has anyone else kept track of how many hours they had into a complete build?

Cut them all with a 1/32 to 1/16 oversize for filing down.

Lengths generally aren't critical, so if the cuts look nice, I would probably just leave the pieces with the small amount of extra length.

I found tapping in alum to be easier and quicker than steel.

Same here, by a lot.

Keep the photos coming.

-Bob

[GTFreeFlyer]

For the tapping, make sure you make a 1/4 turn, then back it out a little til you feel the chips break. Then go in another 1/4 turn and repeat the process.

[skyguynca]

Yep, done alot of tapping of threads in aluminum just 6061 is a bit of a pain. Steel takes me less time. I only do 4 or 5 quarter turns in and back out each quarter then back the tap way out to clear all the chips.

No not alot of free time so I make the most of it. I have alot of experience with wood, aluminum and steel making aircraft parts by hand so this is pretty easy stuff.

I only have a few hours sunday to get some more done. So I plan on just working on the parts from 3/4 x 3/4 stock so I don't have to keep moving the drill press vice around so much. Should be able to finish the last 8 pieces from that stock tomorrow.

Thanks for the comments and advice.

David

[skyguynca]

Ok well I made parts 12, 16,17,18 and 19 yesterday. Did not have alot of time took about 3 hours. Last night however I had some time so I maked and center punched all the rest of the parts so when time allows I can do the drilling.

David

[skyguynca]

Well only got 3 new parts done last night. 13, 7 and 8 are done.

Right now I am writing everyone I can that makes the pulleys.

My stepper motors have 8mm shafts, but all the 10T XL pulleys I can find are all 6mm or smaller...

The only 8mm pulleys I can find are 20 tooth, too big and I will loose a lot of resolution. I might have to redesign for new motor mounts and jack screw like Z Axis if I can not find a pulley.

[GTFreeFlyer]

Based on your username are you in CA? If so, whereabouts?

[skyguynca]

Well I put some of the gantry together. It is just so I can do a bit of figuring and planning. I can't get the 10 tooth pulley for my 8mm shaft on my stepper motors.

So I am in a toss up between Rack and Pinion and lead screw. Both are going to require about the same bit of manufacturing of parts, and about the same amount of cash in conversion.

I figured R&P with pinion gears needing 3 @ $22 and 2 pieces of gear rack 24" long @ $21 so basically around $110, that gives me a drive on both sides of the gantry.

The Lead Screw will be two antiback lash nuts @ $22 each, two threaded couplings @ $18 each, and 72" (can only find it in 3ft lengths) of 2 start 1/2-8 lead screw @ $27 each gives me a drive on each side of the gantry at about $140...

I think I will do the R&P, cheaper and with the right gear ratios I should be able to keep pretty good resolution and I have been working more on this one in my head today while at work.

I will post a cad rendering when I get it worked up in bobcad.

David

[skyguynca]

San Jose

[Mike_Powell]

For the costs you list you could buy two new motors with 0.25 shafts, and avoid any additional work.

[skyguynca]

True but I am trying to keep the same motors, also I don't really need to drive both sides of a gantry on something this small either. I did go with acme screw though, ordered the parts came to $70 for everything to do the one side with.

[Mike_Powell]

Another approach is to disassemble the motors and have a machine shop reduce the diameter of the end portion of the rotor shafts.

[louieatienza]

Another approach is to disassemble the motors and have a machine shop reduce the diameter of the end portion of the rotor shafts.

That may be particularly difficult to do with a stepper motor and is not normally recommended....

If you can get a 5/16" bore you could then drill it out pretty accurately with an 8mm bit, it's only .002" larger or such; might even slideonto the shaft....

[Mike_Powell]

Why would it be difficult? I've worked with a variety of smaller stepping motors and don't see an issue. Certainly it would be important to keep the rotor free of metal chips, but other than that....?

[skyguynca]

Well I have to travel to southern CA for work so my build with have to go on hold. Right now I have 10 days of work so far, and about 37 hours is what I have written down to get to where I am in my build. I will be out of town for 11 days. Then when I get back I start school for the next 18 weeks for CNC Machining Cert. Fun stuff huh? I was hoping to get my momus finished before school started but just ain't going to happen.

[GTFreeFlyer]

I'm not far from Disneyland. I'd tell u to swing by, but timing is just not right for the next few weeks.