I've been chasing down a tram calibration problem and I believe at this point the culprit

I’ve been chasing down a tram calibration problem and I believe at this point the culprit is in my lasercut Makergear y-carriage. I’m looking to replace it with something smaller, simpler and less likely to become deformed.

I’ve seen a number of options out on Thingiverse but if you have any suggestions/recommendations for an upgrade y-carriage for a Prusa Mendel please share :slight_smile:

I really like @Whosa_whatsis 's recommendation of a three-point build surface adjustment system ala Bukobot; if there’s something like that for the Prusa I’d love to give it a go. I’m also considering designing something from scratch but if nothing else I’d like to look at some other good designs for inspiration.


Right now this one is leading the pack: http://www.thingiverse.com/thing:12979

I had to ditch the MG lasercut sled even before I could get a good print out of it b/c the thing was so deformed it was binding on the y smooth rods. I just grabbed some scrap plywood from the shop to make the small lower sled with 3 printed lm8uu holders and attached the upper plywood sheet with the printbed with 4 M4 screws and springs. In hindsight the 3 point system of @Whosa_whatsis using 1 fixed standoff and 2 springs would have been easier. A printed sled like that one just seems like more work than necessary.

Cool, thanks for confirming my suspicions about the MG sled @Brian_Evans , my tests point to that as the problem but it’s nice to have a second opinion :slight_smile:

I’m not opposed to fabbing something like you’ve described, I recently replaced the plywood bed with an aluminum plate as part of my troubleshooting (my first thought was that the plywood was warped), so I could probably cobble together some bearing holders that I could then attach to the bottom of the plate, using countersunk screws (I only print PLA w/o heat so I’m not worried about thermal insulation).

I would like to go to a three-point system though, and I also don’t have any lm8uu bearings on-hand, so I might try printing something anyway (have you tried using printed bearings/bushings before and had any luck?).

@Jason_Gullickson Printed bearings IMO are pointless… you are obviously having mechanical issues so why would you continue making your life difficult? Ultimachine has lm8uus back in stock for $1.75 each and you would need 3 of them. No big deal. I used these bearing holders and they worked well: http://www.thingiverse.com/thing:16158 Along with some sheets of plywood, aluminum, or acrylic you can make your 3 point leveling system and save yourself some heartache.

Cool. I’ll get some on order but I’ll probably experiment with printed bearings the the meantime (gotta have something to do waiting for them to ship right? Thanks!

I just today built a new three point carriage of wood chips. Using som cheap Chinese bushings. I have not yet had the time to test it, as I did some other upgrades. My bushing holders need to be a little higher. But I need to print them on the new carriage. :slight_smile: I will do a test print later this evening/night (here) and put up pictures of the “contraption” :slight_smile:

Looking forward to it!

@Tom_Oyvind_Hogstad I’d love to see some pictures of what you came up with. My bearings came in so I’m planning to start hacking on a replacement for the MG sled tonight so any input I can gather will be appreciated! :slight_smile:

I Think I tried to share it. Here is the link