What size screw is used to retain the bushing on a reamer?

[LVLAaron]

What size screw is used to retain the bushing on a reamer?

Making a grizzly rod out of some drill rod and need to put a retaining screw on the end. Anyone know what the thread pattern is?

 

[Dusty Stevens]

4-40 i think

 

[tobnpr]

Making a grizzly rod out of some drill rod

How? Those are precision ground to the precise diameter needed for the bushing.

 

[LVLAaron]

How? Those are precision ground to the precise diameter needed for the bushing.

Grizzly rod doesn't need to be super precise. The bushing fit needs to be excellent, but the rod itself doesn't need to be perfect. You chuck one end of the rod and indicate off of a stationary part of the rod, so it doesn't matter if the rod is bent.

 

[kendog]

All of my reamers (JGS mostly, with a few random PTG's) are 5-40.
I stand corrected
4-40
Brain Fart.

 

[WillyTP]

4-40

 

[tobnpr]

The bushing fit needs to be excellent,

I use them, it was the bushing fit I was referring to.
Tolerance live pilot fit is .0001 to .0005 max, I suppose you might be able to sneak up on that and stone it or sandcloth with some fine grit to final fit. For me, $45 to buy one is cheaper than I could make it factoring in my time.

Good luck with it.

 

[LVLAaron]

I use them, it was the bushing fit I was referring to.
Tolerance live pilot fit is .0001 to .0005 max, I suppose you might be able to sneak up on that and stone it or sandcloth with some fine grit to final fit. For me, $45 to buy one is cheaper than I could make it factoring in my time.

Good luck with it.

I bought the ones that I could. I don't want to wait 6 months for the 22 cal version from PTG.

 

[GenePoole]

I bought the ones that I could. I don't want to wait 6 months for the 22 cal version from PTG.

I always look at midway before ordering from PTG direct:

PTG Pilot Bushing Set 22 9 Piece

Any gunsmith who does a great deal of work on a specific caliber needs a pilot set. These nine-piece sets are specially ground over and undersized...

www.midwayusa.com

 

[LVLAaron]

I always look at midway before ordering from PTG direct:

PTG Pilot Bushing Set 22 9 Piece

Any gunsmith who does a great deal of work on a specific caliber needs a pilot set. These nine-piece sets are specially ground over and undersized...

www.midwayusa.com

I have the bushings - I need the rod.

 

[tobnpr]

Did you call Dave Manson?
That's who I buy them from, I'd bet he has them in stock.

 

[LVLAaron]

Did you call Dave Manson?
That's who I buy them from, I'd bet he has them in stock.

Hadn't thought of that. On it like white on rice though!

 

[LVLAaron]

Well... I didn't call dave but my drill rod showed up. Got it dead nuts true, drilled it... and the 4-40 tap MSC sent me didn't have enough engagement to start the threads.

Better tap coming soon. Fun little challenge!

 

[tobnpr]

Why not just drill it deeper?
You're probably using a taper tap, easier to align/start new threads but you need a lot more clearance to keep it from bottoming out with the partial threads at the end. Plug and bottom taps don't need that extra room at the bottom of the hole, but without the partial/tapered threads on the tap are harder to get started in perfect alignment. Not as much of an issue when doing it in the lathe, as the tailstock will keep the tap wrench in perfect alignment to the hole.

 

[LVLAaron]

Why not just drill it deeper?
You're probably using a taper tap, easier to align/start new threads but you need a lot more clearance to keep it from bottoming out with the partial threads at the end. Plug and bottom taps don't need that extra room at the bottom of the hole, but without the partial/tapered threads on the tap are harder to get started in perfect alignment. Not as much of an issue when doing it in the lathe, as the tailstock will keep the tap wrench in perfect alignment to the hole.

Nah, just a crappy tap. It wouldn't even start. Got a more expensive one and it worked a treat!