Swapping the Spindle Mount

Hey all,

If you plan to do this you should be aware that there are non-solved problems with swapping the Spindle Mount.

Exactly at this moment in the support video you are told to loosen the set screws on the bottom, back side of the Z slider with a M2.5 hex key. The problem is, these set screws are glued into the bracket, but the video says absolutely nothing about it.

The problems were described in this thread and it was @AndyP who reported in this post that it may not easy to loosen these screws without damaging either the hex fitting or the thread in the Z bottom bracket.

Usually you would await that screws are locked with something like Thread-Locking Fluid but what Onefinity used looks more like Superglue.

A few suggestions on how to loosen screws are described here. If it is Superglue (cyanacrylate), a possible solution for loosening these set screws could be a syringe with acetone. It would however be necessary to remove any acetone remains before reassembling (e.g. using ethanol).

I asked @AndyP whether @OnefinityCNC Support (who very kindly replaced the Z Slider Bracket with the damaged threads) gave some instructions on how to deal with the glue when trying to loose the set screws, but they gave none at that moment.

Tags: 80mm spindle mount

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I can’t recall ever seeing machine screws mounted with superglue or CA. Maybe Red Locktite? If so , heat helps.

Hey Greg,

Me neither, hence my astonishment: To me it does not look like Loctite

EDIT: I just did a little search, Loctite Blue and Loctite Red are both Dimethylacrylate Ester. The directions in their Technical Datasheet say for both:

For Disassembly: shear with standard hand tools and remove with methylene chloride. In rare instances where hand tools do not work because of excessive engagement length, apply localized heat to nut or bolt to approximately 482°F (250°C). Disassemble while hot.

But at the moment, we do not know what Onefinity used as glue here.

Anyway if removal of those Z Slider’s Bottom Bracket Set Screws is required in order to
mount the Official Onefinity Accessory 80mm Spindle Mount, it is up to the manufacturer @OnefinityCNC to provide information on the gluing used and instructions for loosening the gluing.

One quick way to test if it’s CA or not, especially since you’ve got them out now - drop a bit of acetone on them and see if it dissolves the adhesive.

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I am thinking this product may work. I keep it bagged in the fridge along with my super glues as a safety item.

The supplier says it:

  1. Use to clean up and remove CA from skin and equipment
  2. Breaks down the molecular structure of CA

Safety Data Sheet says it is acetone and propylene carbonate. Likely a bit better in this application than just straight acetone.

Screenshot 2021-11-17 203859


I swapped my mount and didn’t have any issues. No heat, no chemicals to break the bond. Just the proper sized Allen wrench and the screw. The screws were tight and “popped” when they broke free but none stripped or even disfigured the hex key hole. I did not see any visible loc-tite or glue residue.

This was from an order that arrived in October.


Hey Josh,

Maybe the issue mentioned above (from begin of September '21) made the manufacturer change something. If this screw behaviour is what we can expect now when attempting to swap the spindle mount, it would be nice if @OnefinityCNC Support would inform us about it.

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I suggest if they are impossible to undo, then they are glued (somehow), and it is possible that more recent machines have not been glued.

Propylene Carbonate: new one to me. I have a few solvents but not that one. I’m curious about how it works. Maybe the same as acetone, but the trouble with acetone is that it is quite volatile and so evaporates (don’t try it on a heated part). Propylene carbonate has a higher boiling point.