Turns out not to be the case but your suggestion got me thinking. I might just be hearing the wood platform creaking and because it's tight to the frame the noise is transferring to the steel like a musical instrument. I once leaned against the machine while I was looking at something and heard the same "clang" as the friction of the wood against the steel gave way.
Then the other day while moving the Y axis towards me I heard the creaking and could have sworn I saw the B sled jump forward like it was binding.
So, jury is still out on that one.
Thanks. Gary.
Jack.
The screws I used are nylon and were $11 for 100 - didn't seem too expensive to me. These particular ones show as not available now on Amazon but they're bound to have others.
David
David
Romans 3:23
CurlyWoodShop - www.etsy.com/shop/CurlyWoodShop
David Falkner - www.youtube.com/user/difalkner
difalkner - www.instagram.com/difalkner
Those are perfect David. Nothing wrong with that price. Thanks. The ones I saw on Amazon were double digits for a handful.
They must be on to me. I swear every time I click buy the next screen says. "Thanks for your order. Listed below are some things you spent 40 minutes looking for but couldn't find."
Jack.
FYI:
Heard that pop again tonight. Always from the right side. Caught it on video but I don't see anything "pop".
Video :
Few notes:
Seems to always happen coming from back to front.
Seems to always be about 2/3's down the rail from the back.
That wobble on the motor shaft belt gear is just the thin metal at the end that keeps the belt on. I slightly bent it a month ago. Just cosmetic.
Thanks.
Jack.
Jack,
Beats me. I don't see anything, but the sound is clearly audible. It's a very different sound than I heard from my cable chain.
Have you tried putting your hand on the right side of the gantry while it's moving to see if you can feel something? If nothing there, you might start putting you hand on various parts of the machine to see if you can feel something.
Gary
Interesting... for months I've noticed ours has a very slight pop on the right side but it is so slight, maybe 10% as loud as yours, that I have just ignored it. I know the machine is well lubricated and when I had the pinions disengaged to change those out I moved the gantry by hand over the entire range to see if I could feel anything. Nothing felt out of order and I only hear the slight noise when the machine is cold and I'm running the gantry from back to front for homing. After that I never hear it again - weird.
David
David
Romans 3:23
CurlyWoodShop - www.etsy.com/shop/CurlyWoodShop
David Falkner - www.youtube.com/user/difalkner
difalkner - www.instagram.com/difalkner
Take a close look at the rack on that side. If there is debris, a small burr in the rack, or even a little weld splatter near where the clunk happens it could be causing the noise.
The anti-backlash adjustment (spring) on these drives is a little bit of a hack, strictly speaking. Backlash is necessary in gears to keep the tips of the teeth from contacting the faces of the mating teeth. There is always a little error in machining the teeth on the pinions and the racks. The more error there is, the more backlash you need to avoid interference. This rack and pinion system is not the highest grade and was not originally designed to have the pinion pushed all the way into the rack. It would cost alot more to get higher grade (more accurate) gearing. That said, the anti-backlash adjustment generally works pretty well for this application. You may just be seeing a spot where there is a little more interference than typical. A small burr, even 0.001"-0.002" is significant in gears this size.
-Robert
All gears have backlash, you can reduce it by shimming or other adjustment. Too tight and temperature changes or other changes can cause issues. Why is a spring loaded engagement a "hack" how else would you hold the the gears in place? You need to look at the work David does with his machine making guitars, the detail in the inlay and tell me the gearing of this rack and piñon is lacking.
1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro
Because the pinion is supposed to be run at a fixed distance from the rack, not pushed into it as tight as possible.Why is a spring loaded engagement a "hack" how else would you hold the the gears in place?
Spring loading the pinion is an easy way to remove the backlash, and get a usable system at a low price. The downside is that the pinions wear a lot faster.
Higher end rack and pinion systems use helical racks and double pinions to remove backlash.
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
David
Romans 3:23
CurlyWoodShop - www.etsy.com/shop/CurlyWoodShop
David Falkner - www.youtube.com/user/difalkner
difalkner - www.instagram.com/difalkner
Thanks guys. Very helpful.BTW mine are not that tight, and neither is Davids.
I'm about to cut the top layer of MDF tonight. After all the work I did prepping I'm hesitant to make any changes. I'm going to try the run as is.
Definitely will back off the tension screws after that.
Jack.
Exactly! I couldn't have said it better myself. I'm not disparaging the FineLine (and similar CNCRP) rack and pinion system. It is designed to a price point and a purpose and does a nice job. I am thrilled with my Saturn 4x2. I considered designing and building my machine myself but realized that I couldn't really match the Saturn for the price. The only drive systems I have seen that look a little nicer in this price range are the tapered rack and pinion systems that KHK America sells:
https://www.khkgears.us/catalog/?cid...strcpf-strcpfd
Or an interesting anti-backlash system from DamenCNC.
https://www.damencnc.com/products/mechanical-components/rack-pinion/q10-straight-rack-pinion/r-p-drive-antibacklash-diy-includes-gears15t/_404_w_363_554_GB_1
I'm not sure how well either would retrofit on a Saturn, though, without alot of work.
-Robert
Well the carriage alone is over $400 each side in USD, plus upgrading the racks, so we are talking $1000 - $1200 more? Did you see the work David does fitting inlays on his guitars? Fantastic. Same rack and pinion we have on ours.
My spring tension is from the top of the black bracket to the top of the washer over the spring is 1 inch.
Last edited by wmgeorge; 09-12-2018 at 09:50 AM.
1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro