Advice for properly tensioning the R&P Tension bolt?

1

Hi everyone, hope you’re doing well. Sorry if this has been discussed previously, I looked around and didn’t see anything relevant.

I’ve had my machine for about a year, I’ve been having some issues with accuracy over the past few weeks, so I decided to go through and adjust, grease, tighten, replace all consumables, etc.

I’ve always found the instructions on properly tensioning the tension bolt on the R&P assembly to be a bit frustrating. Especially the phrase “continue tensioning… until the spring is seated but not compressed”. By “seated” do they just mean that the bolt has been tightened to the point where the spring is touching both washers (the one under the head of the bolt and the one on top of the tension bracket) but no further?

How important is this adjustment when it comes to overall accuracy? When I first built my machine I remember thinking that it would be nice to have a torque value and adjust the tension with a torque wrench. Am I way overthinking this? I followed all of the instructions to a tee, and up until recently I haven’t had any issues, I guess I just want some kind of tangible feedback that I set the tension correctly.

Thanks again, have a great day

2

On mine, I hold the pinion gear against the rack and hand tighten the bolt until the spring isn’t loose (i.e. no play left), then add three turns. Machine is plenty accurate for me when done that way.
Make sure the spring isn’t caught on something, so that it really is applying that pressure against the rack.
Note that aluminum extrusion machines like these aren’t guaranteed for more than 0.005" accuracy as per Avid’s spec.

1 Like
3

Thank you so much! This concept makes perfect sense after reading your comment. If anyone from Avid sees this, I think it may be worth updating the language in the manual in future revisions. This may have just been a me problem, but I’m a fairly mechanically inclined person, and I was totally confused during assembly. The word “seated” really threw me off, I’ve never heard it used in relation to a spring, and I couldn’t find any examples on google. In hindsight I was totally overthinking it, but a little added clarity never hurts. Thanks!