Parker Hale aperture sight threads 7/32-36 TPI

[akaroa1]

So here's a question for you target shooters / real gunsmiths.

I have a lot of Parker Hale sight aperture inserts.
Their thread is 7/32-36 TPI

There doesn't seem to be a readily available in NZ ( or elsewhere ) tap in this size and pitch.
7/32-32 TPI is a thing and available, but no use to me

So who has a tap for the Parker Hale apertures ?
Brand, code, details etc please

[Makros]

That is an odd size. Might be a good case for making your own tap.

[csmiffy]

Bit like the enfield threads. Just made their own up.
Some crazy little numbers on those ones

[11mms]

That is an odd size. Might be a good case for making your own tap.

Yes this is what I was thinking. A watchmaker's lathe and a fine hand!

[No good names left]

You know how to pick the odd projects, I'd have to agree with the others and you may be best making your own as this'll probably happen again and you'll only have to go through the learning curve later anyway.

[00buck]

Machine threads down to 4.90+mm, re thread to 5.0x0.8. they should be around 5.6 originally but in fact I've seen a few slight size variations that made fitting eye pieces from one sight to another a bit of a puzzle. If you could get a 5.5x0.7mm tap you would be in too.
The metric specs for 7/32x36 would be 5.6x0.706. I Think? Any help?

[akaroa1]

Machine threads down to 4.90+mm, re thread to 5.0x0.8. they should be around 5.6 originally but in fact I've seen a few slight size variations that made fitting eye pieces from one sight to another a bit of a puzzle. If you could get a 5.5x0.7mm tap you would be in too.
The metric specs for 7/32x36 would be 5.6x0.706. I Think? Any help?

Yeh
Maybe approach the problem from another direction

My lathe imperial threads run out at 32TPI

[omark]

So here's a question for you target shooters / real gunsmiths.

I have a lot of Parker Hale sight aperture inserts.
Their thread is 7/32-36 TPI

There doesn't seem to be a readily available in NZ ( or elsewhere ) tap in this size and pitch.
7/32-32 TPI is a thing and available, but no use to me

So who has a tap for the Parker Hale apertures ?
Brand, code, details etc please

Best bet would be Mike Collings

[No.3]

Sure it's not 7/32x40 or #12-40?

Not sure that I've ever seen that thread listed as a 36tpi, my little cheat list refers to it as a 40tpi?

[zimmer]

Sure it's not 7/32x40 or #12-40?

Not sure that I've ever seen that thread listed as a 36tpi, my little cheat list refers to it as a 40tpi?

Just checked. I have a range of apertures - AGP, PH 6 Hole, old PH single hole, very old PH 6 Hole (the flat type), Central sight aperture, plus some unmarked ones, and they are all 40TPI.
Have the corresponding PH sight (and Central Sight) from my old 303 range rifle somewhere but the PH 6 Hole came out of it at any rate so no need for me to turn the house upside down to find it.

[akaroa1]

Sure it's not 7/32x40 or #12-40?

Not sure that I've ever seen that thread listed as a 36tpi, my little cheat list refers to it as a 40tpi?

Mmmmm that might be the answer ! 36TPI is a good fit on the thread gauge. But 40TPI is also a pretty neat fit. Typical of ultra fine threads

So I will look into the #12-40TPI taps

[Fssprecision]

Might be worth contacting Tracey Tools in the UK they have lots of unusual stuff

[zimmer]

7/32-40 ME taps may be the jobby. Available in a couple of places in NZ but pricey at ~ 38 bucks.

[akaroa1]

7/32-40 ME taps may be the jobby. Available in a couple of places in NZ but pricey at ~ 38 bucks.

Just going bush for a few days and will get on line over Christmas and see what's available locally

Cheers

[akaroa1]

Well I did track down a full set of 3 taps for this job on loan.



They were only a short drive away and the gift of some fresh venison.
I know where they are for next time I need them.

Nicely converted the tiny edged rimfire sight staff to take the Parker Hale eye cups.
Played around to find an aperture size that gives a good sight picture with the globe front sight



Now I can continue with the load development and have a better chance of grouping with this 140+ year old rifle which has a very good bore