Yet Another 8020 CNC Build

[jsantos]

Originally Posted by CarveOne Primer? I don't use it with Rust-Oleum. It has built-in rust preventative. (So they say.) Try it on a piece of plain steel and see if you get the same results. As long as the steel is cleaned with solvent it will stick pretty well without primer. They have other metallic hammered colors too. Gotta find something to use the hammered copper color on. The stone textured paints look interesting as well. CarveOne

I picked up the Rust-Oleum you recommended and the directions said that a primer provides better protection and better adhesion so I also got a primer and used it.

I cleaned the CRS with kerosene until it was nice and shiny, taped the sides with 1" blue tape (which gives a nice 3/8" on both sides). I then sprayed it with the primer, waited a few minutes and then sprayed the hammered paint.
The wife was complaining because I sprayed in the basement and every though I was using a large fan, the smell still got into the house. :-(

The paint came out looking very nice though. I'll take a picture of it and post it within the next couple of days.

I didnt' want to struggle with removing the masking tape, so after about 4 hours I removed them. They came off very nicely and didn't take any paint with them.

Thanks for all your help so far. I really appreciate it.

Have a Merry Christmas.

[CarveOne]

Originally Posted by jsantos I picked up the Rust-Oleum you recommended and the directions said that a primer provides better protection and better adhesion so I also got a primer and used it. I cleaned the CRS with kerosene until it was nice and shiny, taped the sides with 1" blue tape (which gives a nice 3/8" on both sides). I then sprayed it with the primer, waited a few minutes and then sprayed the hammered paint. The wife was complaining because I sprayed in the basement and every though I was using a large fan, the smell still got into the house. :-( The paint came out looking very nice though. I'll take a picture of it and post it within the next couple of days. I didnt' want to struggle with removing the masking tape, so after about 4 hours I removed them. They came off very nicely and didn't take any paint with them. Thanks for all your help so far. I really appreciate it. Have a Merry Christmas.

It is rather strong smelling and the aluminum dust in the overspray fog is surely not good for the lungs. I like the smells of good Christmas holiday cooking much better.

Merry Christmas!

[jsantos]

Christmas is over and the guests are gone. Now, it's time to get back to doing some real fun stuff - building the CNC. :-)

It's only 17 degrees outside and there's still a lot of snow on my driveway but just can't wait to install the CRSs.

Brought the CRSs from the basement back into the garage, aligned it side by side with the 8020 rails and inserted carriage bolts into the 8020 rails. I tried to align the bolts with the holes in the CRS as much as possible. The installation went much, much better than I expected. I was expecting to take hours to install them but it only took about half an hour.

Now I'm ready to install the carriages. Found CarveOne's build log on his second CNC and found Ahren's recommendation on how to install the carriages there.

On second thought, maybe I'll plow my driveway first. :-(

Here are some images of the work on the CRSs.

crs 1.jpg - One of the CRSs on the drill press. I've drilled one side already and getting ready to drill the other side. BTW, I drilled dry this time like CarveOne suggested and I like it much better than using cutting oil.

crs 2.jpg - The CRSs drilled, cleaned, taped up and ready for painting.

crs 3.jpg - One of the CRSs installed. Carriage bolts have also been inserted on the other side of the 8020 rails in preparation for installing the other CRS.

crs 4.jpg - Installing the second CRS. One end of the CRS is lifted by the wooden blocks so the carriage bolts can be easily aligned with the holes. Once aligned, I move the wooden blocks further down to the other end and the CRS drops down onto the next set of carriage bolts. Easy as pie. :-)

crs 5.jpg - A close-up view of the CRS. Thanks to CarveOne's tip, I was able to get the hammered-effect of the Rust-Oleum paint I was using. Thanks again, CarveOne!

[CarveOne]

Originally Posted by jsantos Christmas is over and the guests are gone. Now, it's time to get back to doing some real fun stuff - building the CNC. :-) It's only 17 degrees outside and there's still a lot of snow on my driveway but just can't wait to install the CRSs. Brought the CRSs from the basement back into the garage, aligned it side by side with the 8020 rails and inserted carriage bolts into the 8020 rails. I tried to align the bolts with the holes in the CRS as much as possible. The installation went much, much better than I expected. I was expecting to take hours to install them but it only took about half an hour. Now I'm ready to install the carriages. Found CarveOne's build log on his second CNC and found Ahren's recommendation on how to install the carriages there. On second thought, maybe I'll plow my driveway first. :-( Here are some images of the work on the CRSs. crs 1.jpg - One of the CRSs on the drill press. I've drilled one side already and getting ready to drill the other side. BTW, I drilled dry this time like CarveOne suggested and I like it much better than using cutting oil. crs 2.jpg - The CRSs drilled, cleaned, taped up and ready for painting. crs 3.jpg - One of the CRSs installed. Carriage bolts have also been inserted on the other side of the 8020 rails in preparation for installing the other CRS. crs 4.jpg - Installing the second CRS. One end of the CRS is lifted by the wooden blocks so the carriage bolts can be easily aligned with the holes. Once aligned, I move the wooden blocks further down to the other end and the CRS drops down onto the next set of carriage bolts. Easy as pie. :-) crs 5.jpg - A close-up view of the CRS. Thanks to CarveOne's tip, I was able to get the hammered-effect of the Rust-Oleum paint I was using. Thanks again, CarveOne!

Don't worry, Ahren's method of mounting the carriages is easier than the vertical mounting scheme that I used. I suppose that I just had to prove that they can work either way. I'm like that.

That's the effect that you should get. Nice job.

CarveOne

[jsantos]

Originally Posted by CarveOne Don't worry, Ahren's method of mounting the carriages is easier than the vertical mounting scheme that I used. I suppose that I just had to prove that they can work either way. I'm like that. That's the effect that you should get. Nice job. CarveOne

I've got a good teacher. :-)

Okay. I followed Ahren's method of mounting the carriages. The first bearing took a little bit of time. But once I got used to the process, the rest of them was easier. The images shows what I did.

car 1.jpg - After mounting the carriages, I cut a couple of 3030s to hold the carriages on each side of the rail. But before tightening the carriages bolts, I wanted to make sure everything is square. Clamped a square to the CRS and pushed both the carriages against it to align the carriages.

car 2.jpg - Clamped a piece of aluminum on the other end of the carriages to make sure they don't move. Also clamped the carriages together to pull them together against the rails.

car 3.jpg - Put another square on top of the carriage to square the 3030 that will hold the carriages. Then tightened the bolts on the 3030.

car 4.jpg - Mounted a 3030 across the rails to test the movement. It works! Except that the side bearings of one of the carriages was not moving. Had to clamp them again and pull the carriages to the rails. Now all the bearings are moving! Moved the 'gantry' through the whole x-axis and it moves very nicely.
Things are looking good! Time to tighten all the bolts on the frame and the rails.

It looks like if I use 3060s instead of 3030s for the gantry, I can eliminate the vertical supports of the gantry in my design. I should have listened to Ahren. Time to look for 3060s in eBay.

Question: What is the minimum clearance that I should have between the collet of my router and the surface of the CNC table? My z-axis will have 7.5"-8" of travel.

[jsantos]

Originally Posted by jsantos I've got a good teacher. :-) It looks like if I use 3060s instead of 3030s for the gantry, I can eliminate the vertical supports of the gantry in my design. I should have listened to Ahren. Time to look for 3060s in eBay.

Wow! A piece of 3060 is going to cost $200. Looks like I'll have to stick with the original plan. :-(

[jsantos]

Ahren,

Can I get away with doing the gantry as shown in the attached image?

I was thinking of using a 4-inch rail and attach the z-axis directly to the carriages.

Would that work?

[jsantos]

Originally Posted by jsantos Ahren, Can I get away with doing the gantry as shown in the attached image? I was thinking of using a 4-inch rail and attach the z-axis directly to the carriages. Would that work?

Hmm, no response. Must have been a really stupid idea. Back to the original design then.

[ahren]

Joe,
Sorry I've been away -- I'm just getting back to things after being off for a week, and I've been trying to get people's Christmas presents out the door.

I think your idea will work fine. 0.001" should be acceptable, but does this consider any sort of cutting load? I'd see what it says with a 30 pound cutting load in the center. The steel will stiffen things immensely, so even if the deflection calculator says 0.005" or so, it should still be OK. Steel is relatively cheap, and now that you're a master with a split point drill, you should be able to do it in no time! Machine is looking good!

Best regards,

Ahren
www.cncrouterparts.com

[CarveOne]

Originally Posted by jsantos Hmm, no response. Must have been a really stupid idea. Back to the original design then.

If I understand your question correctly, I think you are asking about the same thing I did on my build. You need to have at least 1/2" of rail beyond the gantry extrusion for the bearings of the carriages. It matters not whether the rail is horizontal or vertical. I mounted a 4" rail vertically and have a 1"x2" steel box tube behind it instead of an 8020 extrusion. Behind the box tube I have an aluminum plate that connects the Y axis carriages together. My Z axis rail is bolted to the front of the Y axis carriages. The Z axis carriages roll up and down the fixed-in-place Z rail. I didn't want to have the all steel Z rail weight being lifted and lowered in addition to the router weight. There are some close up photos of it in my build log.

CarveOne

[jsheerin]

You might have gone past this point already, but if you can mount your gantry beam from the rear of the beam, you can get more travel across the face of the beam. A picture to demonstrate what I mean:

[jsantos]

Ahren, CarveOne,

Thanks for the responses. I wasn't really sure of how I did the gantry and the more I looked at it, the less I liked it so I went back to Ahren's original suggestion. I'm very pleased with how it turned out. It looked a lot more 'professional' and, well, more substantial. LOL.

I also worked on installing the motors. Assembled them and then tried to install it on the CNC. Hmm, the pinion won't reach the rack. It's bumping against something. Looked underneath and one of the carriage bolts holding the 3030 to the carriage is in the way. Then, it hit me! When I was looking for carriage bolts for the carriage, I went to Home Depot looking for a 2 1/2 inch bolts. They didn't have them, so I went for the 3" instead. What harm could it do, right? Well, now I know. Guess I'll have to disassemble and replace the bolts. Good thing, this thing is easy to disassemble and reassemble.

People, do not use carriage bolts longer than 2 1/2 for Ahren's carriage if you're also going to use his R&P.

I was hoping for 48" of y-axis but it looks like I'll end up with a travel of 45".
Too bad, I wasn't able to get longer 3030s from eBay.

I'm also waiting for the 8" CRS from SpeedyMetals that I'll use for my Y-rail. And it won't be here until 1/4. Oh, well. It's too cold out there anyway - 7 degrees.

HAPPPY NEW YEAR EVERYONE!

Here are some images.

gantry10.jpg - The redid gantry. This one looks a lot more substantial. Hopefully, it will also be much stiffer.

gantry 11.jpg - I used the more expensive 8020 t-nuts instead of carriage bolts for the gussets.

ganty 12.jpg - The carriage bolts that are in the way of the R&P.