I've been building a piece of crap CNC machine out of leftover parts and wood from around my shop. I'm getting the missing bits as cheap as I can. For example I picked up 5/8-8 ACME rod from Grainger, 5/8-8 nuts online for $2 each, etc.
I have a few questions on why some of the more expensive bits are even required.
1) Why bearings at the ends of the ACME rod? The forces on the rod are linear meaning the important dimension to hold steady is along the rod, not letting it go in our out of the end when it is rotated. It seems to me you can accomplish this more easily with simple bushings in the wood to let the rod ride on, and collars against the wood. Why bearings?
2) Fricking ridiculous costs of flanged nuts and crap. Why can't I weld a washer to the face of a nut and make my own flange and save $15-$20 per nut?
3) I picked up a cheap NEMA 23 425oz kit from Longs Motors off eBay. How do I connect 5/8" ACME rod to 8MM shafts? Why do connectors have to be flexible? Seems to me an adjustable motor mount would be a lot easier than misaligning it and depending of a stupidly expensive flexible connector? Why can't I take a chunck of old 3/4 steel rod ($0.50 worth), cut it to about 1/2 long, drill an 8mm or 1/4 inch hold through it, tap in some set screws on the side, and weld a washer to it? I'd have a nice flanged collar for about a buck. Then do the same for the 5/8" rod. Then simply bolt the washers together face to face?
It seems like alot of the "engineering" in these things is not really necessary. Where am I wrong?
Seems to me I can do this whole thing for about $400.
I have a few questions on why some of the more expensive bits are even required.
1) Why bearings at the ends of the ACME rod? The forces on the rod are linear meaning the important dimension to hold steady is along the rod, not letting it go in our out of the end when it is rotated. It seems to me you can accomplish this more easily with simple bushings in the wood to let the rod ride on, and collars against the wood. Why bearings?
2) Fricking ridiculous costs of flanged nuts and crap. Why can't I weld a washer to the face of a nut and make my own flange and save $15-$20 per nut?
3) I picked up a cheap NEMA 23 425oz kit from Longs Motors off eBay. How do I connect 5/8" ACME rod to 8MM shafts? Why do connectors have to be flexible? Seems to me an adjustable motor mount would be a lot easier than misaligning it and depending of a stupidly expensive flexible connector? Why can't I take a chunck of old 3/4 steel rod ($0.50 worth), cut it to about 1/2 long, drill an 8mm or 1/4 inch hold through it, tap in some set screws on the side, and weld a washer to it? I'd have a nice flanged collar for about a buck. Then do the same for the 5/8" rod. Then simply bolt the washers together face to face?
It seems like alot of the "engineering" in these things is not really necessary. Where am I wrong?
Seems to me I can do this whole thing for about $400.