Second Kitless Attempt and issues

[Russ Hewitt]

I used a blank from Turnt Pen Co. It cut like butter and is gorgeous. I had issues cutting threads with the tap. I was careful with my measurements. The tap would go in but actually chewed up the plastic rather than cut the threads. I then used the next sized up bit. The tap cut very shallow threads that would not hold. I was able to fix it using UV glue and re-tapping the threads. Any suggestions?????

 

[Displaced Canadian]

Possibly some junk caught in the tap. Or possibly the tap was crooked. I've used glue to build up materiel before and it works well.

 

[duncsuss]

What are the specifications of the tap and the two drill bit sizes you used?

Had you turned down the pen barrel or cap to size before you started drilling and tapping? And how were you holding the workpiece and the tap whie tapping?

 

[Russ Hewitt]

What are the specifications of the tap and the two drill bit sizes you used?

Had you turned down the pen barrel or cap to size before you started drilling and tapping? And how were you holding the workpiece and the tap whie tapping?

I start with a round blank. I turn the tenons first and cut the threads and then drill and tap. I turn it down last using a collet chuck. I have a mandrel for the section. I actually have a set of Hinze mandrels but the rods are too long, so I didn't use them. I may cut them off and try them. I really like using the collet chucks because they are secure and don't mess up the work.

 

[duncsuss]

I start with a round blank. I turn the tenons first and cut the threads and then drill and tap. I turn it down last using a collet chuck. I have a mandrel for the section. I actually have a set of Hinze mandrels but the rods are too long, so I didn't use them. I may cut them off and try them. I really like using the collet chucks because they are secure and don't mess up the work.

Now I'm getting a bit confused - why make a tenon first if you are trying to tap female threads?

It sounds like your intention is to use dies to cut male threads on the outside (such as the barrel end where the cap screws on the outside and the section screws into the inside) and taps to cut female threads inside. If so - reverse the threading, do the outside threads completely first.

Then take a piece of larger diameter stock (I use 1.5" Delrin rod) and drill and tap it to make a screw-on collar. Screw this onto the threads of the pen barrel nice and snug, then drill and tap the inner threads.

This will reduce the flexing of the thin barrel wall as the drill bit and tap turn inside - it made a huge difference to the quality threads when I adopted this approach. (Also dramatically reduced the number of snapped-off tenons on my nib sections.)

 

[JamesC]

I used a blank from Turnt Pen Co. It cut like butter and is gorgeous. I had issues cutting threads with the tap. I was careful with my measurements. The tap would go in but actually chewed up the plastic rather than cut the threads. I then used the next sized up bit. The tap cut very shallow threads that would not hold. I was able to fix it using UV glue and re-tapping the threads. Any suggestions?????View attachment 338844View attachment 338845View attachment 338846

That looks like a piece of "Inlace" I have had no success threading, I like the stuff so put in an acrylic sleeve that can be threaded easily.
Jim