I have a pattern and stock that I’ve been using for a while (3mm birch ply, simple finger joint box) and it always came out with a super tight friction fit. However, over the last week or so things don’t fit tightly and I’m seeing that I need to use glue to get the box together.
I’m not sure what is going on, to be honest. I may have juiced the power a bit (I’m using non-proof grade and had some stock with big glue filled voids). But it may also be a software update in terms of focus that changed the size of the kerf. Or perhaps the machine/laser is ageing and that accounts for it.
Has anyone else experienced inconsistencies like this over time?
do you measure your materials with calipers? even if it’s the same material, it’s not at all uncommon for one sheet to be a slightly different thickness than others. and that can affect the fit you get.
it could be worse, if it was slightly thicker, then you may have a fit that’s too tight.
I had already adjusted for the kerf and things had been working fine.
I think it was a difference in power. I played around some more today and now things are tighter. I was doing 130/FP and things were really loose. Taking it down to 160/FP made a huge difference in the kerf. More than I would have thought it would.
The serration trick looks really interesting. Not sure how it would work on corner finger joints though. Might be something to add to the OnShape extension I use to do the tabs.