Are the rails/bearings new?
After a few years of collecting THK parts and various other parts I think the new machine can be started.
I have laid out the parts for my new machine in the following photos.
Frame: 80/20 3030 and 1530, all precut from supplier.
Gantry: 80/20 3060 and 1545 with .75” thick aluminum uprights, holes drilled by local machine shop.
Rails: HSR25 for X(48”)/Y(38”) and SHS25 for Z(13.5”).
Bearings: HSR25A/B and SHS25C.
Screws: ACME X(1/2-10 2 start), Y(1/2-10 2 start),Z(1/2-10 single start).
Nuts: Dumpster and CNCRP.
Screw Bearing blocks: CNCRP.
Motors: Steppers X/Y 620oz, Z 380oz.
Spindle: Porter Cable and Wolfgang.
I have included pictures of my first machine which I will need to cannibalize for parts to build the new one. After I make a few parts for the new one J
Thanks for looking, comments are welcome.
Are the rails/bearings new?
Today I cut the legs on the CNC, they are made from Baltic Birch. Dimensions (LxWxH) 10"x2.25”x7”, I will be laminating them together. On the bottom of each leg I will be mounting a hockey puck.
I also made a bearing block for my screws. On my first build I made 2 mistakes, first I did not make the frame strong enough. Second I did not understand the importance of bearing blocks for the screws. All of my screws have the ends machined like the picture below. It shows the free-wheeling end, instead of using the expensive blocks from CNCRP I decided the free-wheeling end just needs to be supported to prevent whipping like crazy. On the driven end I will be using CNCRP bearing blocks and thrust bearings.
Yes they are all new. I have some other used blocks but I would rather use the new ones and keep the used ones as spares.
I had a problem with my CNCRP sleeve blocks apparently deforming under even mild tightening, making the Acme difficult to impossible to turn by hand. I cut the shoulders down about 1/4" on the one I ended up using and it now works fine. (EDIT: disregard if you're using the bearing blocks that you made.)
Roy, was that the "low profile" block or the larger block with a bearing?
To attach the rails to the 80/20 I will use "8020 T Slot Roll In T Nuts 15 S 1/4-20 13096 N". ( eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices ) I bought some 1" 1/4-20 socket head bolts and the proper washers from fastenal. The hole diameter in the THK25 series rails are .2756 this leaves me a little bit of wiggle room and the nuts are somewhat self centering in the slot. In testing the fit was very nice. I could not find similar nuts in metric thread and the bolts would have been special order and more expensive.
Today I made the mounts for the Dumpster nuts and a couple more of the orange bearing blocks. I think that just about does it for parts that I need to make before tearing down this machine. Maybe tomorrow I will start the teardown. The legs for the new one are laminated and now need to be painted. I wanted them to set for a day before sanding and painting.
I did a bit more today.
Earlier I asked a question about http://www.cnczone.com/forums/diy-cn...ing_voids.html . The measurable difference between filling them and leaving them open may not be much but at this stage why not, will it hurt anything?
I made some plugs for the ends of the 3030 which also fit the 3060. I don't think the area inside the 1530 would amount to much. I should do the math though just to be sure.
I also made a mount for the X axis DumpsterCNC Nut. I really wanted to make it out of ali but my machine is not stiff enough to cut ali I made it from .5 UHMW Polyethylene and reinforced with 2 corner brackets. The brackets will need to get a hair-cut to clear the undercarriage. I made two mounts just in case more strength is needed. The nut shown is not the one that I will be using.
I recieved my new motors and other assorted parts from Ahren today, thanks very much Ahren! That was fast!
I have a question on my Z axis, as I want to use parts I have on hand and I will be using a single start ACME 1/2-10 screw but looking over a comment Gerry made about single start screws he thinks it may not have the speed needed. Should I use a timing belt system on the Z?
That is a good question Don!
My current machine uses a 1/2-10 single and has been working ok, however I have not routed anything faster than 50ipm and only 2D. If I want to do 3D reliefs at 50+ ipm I’m wondering if a single start screw will be ok. That is assuming this new machine will cut at speeds of 50+ipm!