But I did design it with this ebay listing in mind:
linear bearing slide SBR16 (6 supported rails+12blocks) | eBay
As C1 has said I will probably add the triangular side pieces if there is an excessive amount of flex.
As for the lead screws I'm going to be using 12mm, 2 start trapezoidal screws with dumpster AB nuts.
Will 2 start screws make a huge difference over the 1 start for this size of machine?
Last edited by praneetn7; 03-05-2012 at 06:08 AM. Reason: Added question
I'm not sure if Don kept his single start ACME screws on his build of almost the same size. He has a very nice build here http://www.cnczone.com/forums/diy-cn...ry_router.html
Hope this helps you.
Did u find that the ballscrews in the acuators make a huge difference in accuracy over the acme?
I probably will stick to the 2 start Trapezoidal as it is only going to be about $20 extra and will theoretically double my speed.
TBH I did get my inspiration from your machine.
I typically cut at 20-30 ipm with my acme leadscrews. I'm hoping that I'll be able to cut substantially faster with the ballscrews. I hope to reduce 20 hour jobs down to 5 hours. (That's the only way I can "justify" the expense and hassle of the actuators.)
Most of the things that i will cut will be shorter runs (like 1-2hr jobs or less).
Well from what I have heard the trapezoidal will do just fine
I am going to have the thrust bearings between the radial bearing and a collar to secure the screw and on the stepper side i will have a thrust bearing between the radial bearing and the shaft coupler will secure it down.
Does this make sense? I couldn't rephrase it any other way..
Last edited by praneetn7; 03-06-2012 at 02:39 AM. Reason: rephrasing
I think I understand what you're saying about the thrust bearings. To be clear, you need to have two thrust bearings, one on each side of something fixed to your frame. You don't want to use the bearings in the motors as thrust bearings. Not recommending that you do what I did but I just uploaded a photo of the bearings I'm using. Here's a link: http://www.cnczone.com/forums/1078437-post228.html (New DYI Fixed Gantry Router Build) (The photo on the left shows some tapered roller bearings I'm going to install. The second photo shows much simplier and much less expensive thrust bearings that I purchased from CNCRouterParts.)
So would this be suitable?
Yellow = Thrust bearings
Red = Bearing blocks with radial bearings
Green = Lead screw
for ballscrew end bearings you should be looking for cheap chinese
ballscrew endbearings in the FF and FK type, and have your ballscrew or leadscrew machined to suit.
I like your side panel members, they are similar to mine. You should think about doing the same thing on the Y axis ends, but do them in aluminium, maybe about the 16 to 20mm that the others were saying.
it is the ballscrew end bearings that got me too.
i also got my bearings from linearmotionbearings2008.
don't define your machine around the parts you find of their site, ask for an email address and go through a quoting proccess to get exactly what you want.
his ballscrews are nice and cheap, don't rule them out just yet, he will get them machined at a really small fee.
however last time i asked he would not supply those FF and FK end bearings you'll have to find another supplier.