Loose Feet / Corner Locks

I’ve looked at two other topics with the same issue (Feet are a bit loose and Parts too loose?) but the conversations kind of peter out with no clear resolutions and looking at the dates they seem pre-primo (I’m printing primo).

My bars are 25mm OD on the nose with no detectable ovality, I’m printing the F parts and all other parts I’ve printed so far are fine but the feet and corner locks both show about 25.4mm ID.
(Precisely, my z clamp’s ID is 25.20mm +/- 0.02mm but the feet ID are 25.38mm +/-0.02mm)

As an indication of printer accuracy (or lack thereof), my measured dimensions for the corner lock bounding box are 39.32mm × 29.14mm × 46.22mm (all measurements +/-0.02mm).

Is it me, my printer or the parts and are there any suggestions?

I was thinking mixing some fine sand and glue to bind the parts or simply a strip of duct tape to locally increase my pipe OD?

@vicious1, do you know the answer to this?

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I just grabbed an “F” corner lock off the shelf and mine are printed with almost the exact same outer dimensions you listed, super close, but the inner diameter is 24.97. Check to see if your slicer has “hole compensation” (or some other verbiage)turned on.

Some slicers make a hole larger to account for printers shrinking them…these are designed with the shrinkage accounted for. I have not had any other reports of this in a long time so I am pretty confident this is what’s going on.


Thanks for the responses.

Chasing up on that lead for my case (PrusaSlicer) gives a setting called “xy compensation”.

This will effectively expand or contract the entire model in the xy plane, not just the holes. This shouldn’t be an issue for me since that won’t impact the feet or corner lock function but for those coming after me bear it in mind if you have multiple mating faces.

I’ll print off a corner lock to test and report back.

In PrusaSlicer, setting the “xy compensation” to 0.15mm in my case produced a corner lock that is precisely 25mm (+/- 0.02mm) ID.

Perfect fit, I even have to work it in gently.

Outer dimensions are now 39.62mm x 29.16 x 46.58 (all +/- 0.02).

I am not sure if there will be a negative impact for the locked nut in this part, I’ll report back if so.

For others who come across this post I suggest testing on either a foot or a corner lock.

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Just coming back to confirm that the locknut fits fine. Snug, but it seats fully.