Threading plastic / inserts

[EddyCurrent]

Or are press fit inserts the answer? What sort of pull out loads would I get from these:

Could you use these headed types inserted in such a way that the force is trying to pull the head through ?
You could of course recess the head so it's flush with the surface.

http://www.insertsdirect.com/acatalo...it-insert.html

[jimbo_cnc]

It's not so neat using headed ones but could be done. That's why I'm interested in the straight ones. I'll have to get some data or samples and give them a try.

How would I make the needed 5.4mm hole all the way through 25mm thick delrin? Would that simply be a 3mm mill (or 4mm ?) I'm not familiar with sizes yet and how deep you can go, so much to learn.

[EddyCurrent]

How would I make the needed 5.4mm hole all the way through 25mm thick delrin? Would that simply be a 3mm mill (or 4mm ?) I'm not familiar with sizes yet and how deep you can go, so much to learn.

Yes you could use a smaller end mill, it would spiral down to make the required hole, there are several strategies for hole drilling.
These are the drilling operation parameters for Cambam for example; http://www.cambam.info/doc/0.9.7/cam/Drill.aspx
The cutter size would have to such that the chips could evacuate the hole easily.

[Clive S]

How would I make the needed 5.4mm hole all the way through 25mm thick delrin? Would that simply be a 3mm mill (or 4mm ?) I'm not familiar with sizes yet and how deep you can go, so much to learn.

You could just buy a 5.4mm drill http://www.tooled-up.com/product/tro...i_YaApN58P8HAQ

..Clive

[jimbo_cnc]

yes, I'm aware of drills :)

What I didn't spell out was that to use the suggested headed inserts I would have to go all the way through my material 25mm and then counterbore it, and that ideally needs to be done with the same tool that can profile that face as well.

Whereas with the unheaded insert I just need to mill (or drill) to a depth of about 10mm with no counterbore.

[jimbo_cnc]

Rob, the expanding type unheaded inserts look like the ones for me.

I'd seen those so I don't know why I didn't mention those in the first place! I think it might have been because I didn't like the look of the non-expanding unheaded ones, so they were on my mind when I posted !

I've just thought, you could use those unheaded ones in counterbored holes, giving a more compact design than headed ones.

But the barbs on them do suggest they are for one-sided operation.

Anyway, i've requested pull-out data for use in delrin.