Adjustable Y Idlers - Reprise (Page 1 of 2)

Very nice, again!  I was going to pop them off to re-lube tonight because apparently the first coat of lube I put in there wore off pretty quick and it developed a fairly loud squeek, so I will try this version too.  If I am understanding correctly, it just slides into the top and side frame instead of just the side, right?  Then line it up and drill the holes.  Can we get the STL's please?

The metal frame flex was obvious when I first installed these.  FYI, it is very easy to over tension your belts with these and induce Y- skip.  One time I did it so much the printer didn't move at all in the Y direction and just made a horrible grinding noise when i started it up.  So I backed off about 1.5 turns and it was fine after that.

To eliminate the flex, I was going to try these with an idler bar across the front of the machine next, but this might be a cleaner way to eliminate the flex.  I might loose a little print area off the front of the bed like that.  I've got a couple more 6mm bore GT2 pulleys on the way and I have several lengths of 6mm shaft and I was going to print a collar to install next to the pulley holders to keep everything in place.  I was going to just scale up the first generation of these brackets by 1.2 in the Z axis to fit the 6mm shaft in there.  Anyway I could also get a version of these gen 2 idler holders sized for a 6mm shaft in case I want to try that combination?

Also, for anyone who is afraid to knock out the PEM nut or drill into their printer- don't be, its very easy. 
1.  Remove the existing brackets.  Unfortunately, Solidoodle seems to glue them in. One screw came out with significant effort, the other was stripped.  So I had break the existing mount and cut the bolt with my dremel.
2.  Take the paint scraper you use for removing prints from the bed, grab a hammer and gently tap down on the top of the nut, right next to the frame.  It will pop right out.
3.  Then line up the new bracket, mark the holes, and drill away.  You can even start the drill with the part still in there.

Edit: redbarret mentioned something in the other thread that I think got overlooked: if the bracket also touches the outer (left and right) sides of the frame as well, then it is distributing the load to 3 corners and should provide the most rigidity.  Do these do that?  I'm not at home to look at my printer with the first gen adjustable idlers on it.

Heh, I actually just went away from adjustable idlers and put on the overkill idlers on thingiverse. If you tighten the collars correctly, the frame does not flex and you do not need the idlers to support it. I don't know about hose clamps. The adjustable idlers on my SD4 were actually a serious source of lash. I like the design of these better because the pulley can't tilt, and it is supported at the rear instead of the front. The deflection on the stock SD4 idlers is significant enough that I'd be surprised if anyone ever eliminates Y lash using them.

For anyone curious about how to properly tighten the collars so the frame doesn't flex, there's a little more to it than shown in the video. You need to loosen the front collar, push the rod back against the (tightened) rear collar, and then push the front collar into the frame using pliers. Then, tighten the set screw. It's easier if someone can help. I even pushed my weight into the frame so that the frame is really pinched into that front idler. I can tell you that doing this, the frame is far from flimsy. The rods are supposed to support the frame.

You can tell when the collars are too loose because the belts will tend to rotate a bit along the Y axis when direction changes.

The thicker frame piece is actually for my future printer, which is still in fabrication but thanks, it will be used eventually.  Yes, I want to run a 6mm shaft across the entire front from idler to idler.  I think it might help avoid flex.

I was talking about scaling the gen 1 idlers that you posted in the other thread, not these ones.  These obviously cannot be scaled because they align on the corner too.  And I was only going to scale in the Z direction only, not overall.  That way it should not really mess with the hole alignment, just make them a little taller so I could fit the 6mm shaft in there.  But if you wanted to make me a 6mm version too, I wouldn't turn it down.

I'm thinking that if I drill out either piece for 6mm, then it might be too weak since there is already not a lot of extra material in there. 

PS: when you did the alternate belt tension carriages, did you use the nut trap pieces or the threaded into plastic version?  I used the nut trap pieces and it was perfect.

They couldn't afford me...

Here is how they mount in the frame:

And here are the STL's.  This is a complete layout.  I split off the back face of the piece to make it easy to print.  Once printed you can glue the back plate to the back of the main body, or if you don't want to bother with it, you don't have to.

The "Y Belt sprocket holder - Alt (mdrVB6) (back plate only).st" is uniquely for mdrVB6 since he has an thicker (2.75mm) frame.

NOTE: This part was designed around the GT2 idler pulleys, which are slightly narrower (shorter) than the stock MXL.  As such you'll find that you may need to do some filing to accommodate the MXL pulley and have it spin freely.

The layout already contains the normal & mirrored (left & right) parts.

I was exited to find these idler for my SD4, since the original idlers are horrible and the frame seems a bit flimsy. But, these don't seem to fit SD4? Just printed the left one yesterday, but it seems SD4 would need a taller idler to reach the top of the frame, and there's also the door hinges that are screwed to the frame that'd need cut-outs on the the left hand idler.

So I'm wondering, does anybody have a version of these idlers that's modified to fit SD4?

Thanks in advance,

veehoo

No worries, I get it and was more asking if someone had a modified version. Thank's for the idea, I may try to modify it to fit my printer if no one has done it yet.

There is no reason you can't achieve excellent results with the proper modifications on your SD4.
Reach out to users heartless and jagowilson, both run SD4's and their prints are fantastic.

Nothing in your first post sounded pessimistic, more like realistic.  You'll fit in nicely here, lots of great folks here.  Just let us know how we can help.

heartless, very cool. Will definitely try your idler. I have also checked your prints as per the Moderator's suggestions and they are definitely high quality so feeling a lot better now

Sorry, just seeing this now.  I modified these idlers to fit the stock holes on an SD4.  I'll post it from home later on but if I forget, shoot me a PM to remind me.  They work great.