First of all, thank you all for the wonderful posts and conversations on this forum. It has been so helpful reading various posts. I have been planning my MPCNC for awhile and have been working on it slowly as time allows. Today I was working on the core and ran into the problem of the rails not touching all of the bearings on the core clamps. The rails are not touching the top bearings. The print files I used for the parts I downloaded in August. Attached is a picture. I have seen so many sleek builds with nice color combinations. I was going for the red and black look, but then ran out of red. So then I was going for red, black and yellow. But I ran out of yellow and black. So here is my red, yellow, black and white MPCNC. I have also attached an image showing the top bearing not touching on the core.
I am wondering if the problem is that my core clamps are not tightened enough. The build said that it was too be only 7in/lbs and really gentle. Now I will say I am 6’-4" 300lbs so I dont do gentle really really well. As soon as I felt any pressure, I stopped tightening it. Today when it was so loose, I tried tightening them a little, and it may have gotten better, but when dealing with bearing gaps so small, it is hard to really know. Any help would be most appreciated.
As a random aside, if you live in the LA area and are building a MPCNC, I was able to get (3) 6’-0" stainless steel pipes for $40 at
Bobco Metals
2000 S. Alameda St.
Los Angeles, California 90058,
I wasnt even planning on going stainless steel, but this was so cheap I went for it.
As an update to my post above. I went ahead and decided to just trying tightening up the bolts to see if that was the cause for the rails being too loose, and it worked. I must have just been using too light of a hand. After that, I decided to double check and make sure my trucks were still properly squared, and found that they had somehow gotten off. Not sure what I did. So I went through the process of trying to tighten and loosen bolts to get them squared. After working here and there for days, I started to get nervous that I was ruining the proper tension I had put on them when I first placed the bearings and bolts. At this point I also realized that part of my problem was the truck clamps were not tight enough and so the trucks were rotating a bit on the rails themselves. I took it apart back to placing the bearings in the trucks themselves, tensioned these bolts, and got the trucks squared. The core is now on and I am working on the best way to drill the required holes in my stainless steel. I am using a cobalt bit and found that I have to apply oil every few seconds to keep it from starting to smoke. I am using rail cutoff scraps to test the cutting process. Now I just have to figure out how to create enough of a punched dent to keep my drill bit from skipping when I first start drilling. I realized on one of my punches that while I kept banging on it to make the divot bigger in my pipe, I was flattening the head of my punch (oh well). Hopefully all this detail helps anyone else who run into the same problems.
