What is this?

T

tmenyc

H-M Supporter - Gold Member
H-M Supporter Gold Member
Joined
Oct 18, 2018
Messages
465
It's a tool I use in restoring vintage fountain pens, restoring internal threads in a particular pen type. It's 9mm wide, 48tpi. Looks like a tap except that its flutes are spiral, not vertical. What did it start off life as? Was it an end mill of some kind that was tapped? I borrow this one from a friend when I need it, it was made in England, and I'd like to make my own plus others. Any ideas?
291050

Thanks for the help!

Tim
 
Looks almost like something one would taper or tune-up the insides of compression fittings or the likes. Thinking of a fairly soft (like brass) fitting that needed an inside taper seat to match the male component of same. That's just a shot in the dark though.

-frank
 
Looks like a thread chaser & chamfering tool for cleaning up/restoring existing threads that are damaged. Similar tools are available for valve stems (schrader valves).
 
darkzero said:
Looks like a thread chaser & chamfering tool for cleaning up/restoring existing threads that are damaged. Similar tools are available for valve stems (schrader valves).
Click to expand...


I agree with Will . :encourage:
 
Just reread the post.... looks like you already know what it's for & you were asking what it's made of instead of what it is. Thread title threw me/us off.

I doubt it's made of an endmill (hss, certainly not carbide). I suspect that cause it's got threads on it. Probably made of a high carbon steel, threads single pointed, chaser & chamfer edges cut, then hardened. Chaser & chamfer edges stoned/touched up afterwards or they could have been ground after hardening.

If it's for fountain pens made out of brass or something soft, it might not even need to be hardened.
 
Yes, it is exactly a chaser and reamer, made of mild steel, to cut celluloid acetate, not metal. What I'm wondering is did he add the threading to an existing tool and cut it off to this length? If so, what was the tool he used? A 9mm tap with 48tpi? A tap without threads?
Tim
 
It's probably made from scratch. Wouldn't be that hard to make. Single point the threads, grind in the chaser relief. A thread chaser like that is an old mechanics trick. When I worked in automotive I'd often make a cut like that on bolts to chase a thread. In fact certain bolts on cars come stock like that.
 
Brilliant -- now that I see it that way, makes perfect sense. The view from the bottom seems so regular, though, it certainly appears to me to have been a mass-produced item, with or without the threads.

291067
 
Looks pretty simple to make. Turn it, taper the tip, thread it, put it in a square collet block in a vise that is mounted to a tilting angle table and make four passes with an end mill. Or do the same thing in a chuck mounted to a rotary table that is mounted to a tilting table. If you harden and temper it, it should last for a long time.
 
You must log in or register to reply here.
Back
Top