threading and tapping resin

[Chasper]

I have an order for a turned screw on top box/tube to be made out of the same resin as two pens that will go into the box. I'll need to get a tap and die set for either 1 1/4 or 1 1/2. I'll have to make a casting at 2" or so diameter, and some matching castings at standard pen blank size.

What about turning these large threads in a resin turning, is there anything special I need to know? Any special tools or just the same threading tools I would use to cut wood? Should I get a metal cutting tap and die set?

 

[ed4copies]

Gerry, I have not done this, my answer is "educated speculation":

First, the "coarser" the thread the better--a "wood" thread would be better than a "metal" thread,
Second, pour your resin with as little "activator" as possible. The more brittle your mixture, the more likely your threads will "flake off" down the road.

I know some of the members here HAVE threaded resin. IF any of them offer opinions---THEIRS is better than MINE!!!

Good luck!!

 

[Chthulhu]

The problem with taps and dies in these diameters is the fairly long lead-in portion of each; your cap and the thread on the box will have to be quite long to get enough full thread to be useful. Not impossible if, for example, the cap is half the length of the box; plenty of length for the threads that way.

You're still better off with single-point threading, but regardless of method, cut the threads before boring out the box so there's plenty of support for the tool pressure. Likewise, cut the internal thread on the cap before turning the outside diameter.

 

[tommyd]

don't know if this will work but why not pour the resin around a 2" bolt.
wipe bolt with silicon so the resin won't stick and just un screw when resin has hardened .

 

[ldb2000]

don't know if this will work but why not pour the resin around a 2" bolt.
wipe bolt with silicon so the resin won't stick and just un screw when resin has hardened .

The problem is that PR shrinks while it hardens so the inside threads (those formed around the bolt) will be a little larger and the outside threads (those formed by a nut or mold of some kind) are going to to be too small and my not tighten up well and may break because of a sloppy fit .


It would be best to use the highest thread count you can get to avoid the PR chipping when the tap and die bites into the PR , higher thread count = smaller , less agressive cuts in the resin but more turns to screw together . Also higher thread count taps and dies are quite expensive .

 

[dogcatcher]

You might want to check the tap and die prices before you jump into this. When you get that big, they start to get pretty pricey.