Thread: Rockcliff Router Build, MDF
Or better still not bother and buy some cheap Acme lead screw with a more fitting Dia and pitch. You'll nail several birds with one screw.!! So to speak.
Threaded rod is a multi edge gotcha sword in that the pitch is small which requires you to spin it fast and still get low speeds. The Thread is poor and abrasive which at high speed wears nuts away very quickly. The thread pitch varies wildly along it's length so isn't accurate. It's highly inefficient so zapping motor torque which you don't have spare because the motors have to spin fast just move at what is a relatively low feed rate.
If you can't afford ballscrews then Lead screw is the next logical choice. Threaded rod isn't and shouldn't even be considered other than for bolting the frame together.!!
I seem to have inadvertently dropped into that deep black hole that is called threaded rod ,to use or not to use. My object in starting this cheap build was to have some fun and put my 72 yr old brain in gear again. I already had a design in my head using toothed belts when I stumbled across the part built Rockcliff on ebay, so I decided to stay with the Rockcliff design and see if I could finish it fairly quickly. The next 3-4 week should see it done then onto version 2 with Acme screws, Dumpster anti backlash nuts, 1200mm x 900mm bed, Kress spindle and Artcam Express if I can afford it. I read as much as I can on this site and its American cousin so with the positive help that always seems available here version 2 should be the one
Given where you are coming from and where you are going, then I would have thought that threaded rod for a short-term, cheap, solution would be fine. Can it handle high speeds? No. Can it handle heavy or 5-days-a-week commercial-type use? No. Will it wear out nuts fairly quickly? Probably - but see below. Will it work and give you something to play with, as well as do something useful, while working on Mark 2? Yes. Use stainless rather than BZP as it's much smoother, but if it's any reassurance, the M10 leadscrews on my JGRO router together with the Delrin nuts have been in use, intermittently, for the last 3 years and have done many useful jobs in that time. They are far from being the weakest part of the design. And I've never needed to adjust the anti-backlash nuts in that time.
It's always possible that this machine will encourage you to be even more ambitious for the Mark 2!
Don't see the point because You'll buy TR16x4 for around £15 mtr which provided you build the frame strong means for just a few dollars more you'll only need to do it one time and have usable machine not something your constantly chasing issues with.
You'll have none of the hassels that come with threaded so won't be chasing accurecy or reliablity issues meaning you can get on with using the machine for the purpose intended.
V2 can then be down properly with Ballscrews and Linear rails if required.!!
I've seen too many people give up on Cnc because of these machines. Mostly because they used inferior and wrong components which makes think building a working machine is much harder or costly than it really is. When the reality is if they'd just spent a little more on the right stuff and took a little more care with building they'd have working machine that usable and reliable.!!
Last edited by JAZZCNC; 29-09-2015 at 05:19 PM.
Posted at the end of September about finishing off a part built Rockcliff moving gantry design that I bought on ebay. As usual thing got in the way and only the last couple of weeks have seen it in running order, not finished you understand but working. I had no trouble with the mechanics and the electrics were fairly easy(arduino uno, protoneer cnc shield, 4 A4988 drivers and 4 Nema 23 motors). My problems start with my lack of knowledge about g code, everything I try to cut is back to front and a mirror image of what is on screen in UGS or Grbl Controller also I don't seem to be able to know where the job is going to start despite setting all axis to zero and positioning the router to the bottom left of the bed (1000mm x 500mm). I generate the g code file in either Easel or JSCut. Any help would be greatly appreciated
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