Screw Size Lyman Hawkens

[lonewolf5347]

I am installing a Lyman rear peep on a Early made investerarm Hawkens.
The rear sight holes to be filled with small screws
Antony know what size they are.
I had a small bag of screws can't remember we're they are .
Maybe home Depot will have what I need.

 

[Pete G]

You could fill the hole with a lead shot and lightly hammer it flush. Fills the hole and doesn't leave a slot showing.

 

[smo]

I don’t recall the thread size, but think it’s metric... Home Depot.... maybe, a local gun shop ... more likely.

 

[Gonetocamp]

Contact Dixon's Muzzleloading in Penna. They are a warranty shop for Lyman and should have the screws. They will be metric.

 

[bubba.50]

6x48

 

[Zonie]

6x48

6 X 48?'
The Unified screw thread chart used in America doesn't list a thread that size. They do show a #6-32 and a #6-40 thread but no 48.

I would expect the thread to be a metric size because the gun is built in Italy but it couldn't be a 6mm thread. Those are almost 1/4" in diameter.

 

[bubba.50]

6 X 48?'
The Unified screw thread chart used in America doesn't list a thread that size. They do show a #6-32 and a #6-40 thread but no 48.

You need to upgrade your library with a book at least as recent. As the 20th century. 6x48 is a very common size for attaching sights & other small parts to both muzzleloaders and modern guns. Even my usually useless local hardware has a drawer full of them in their gun screw section.

 

[OldRust]

6-48 is a non std thread size commonly used for sights, scope base to receiver mounting on modern rifles. I have a set of the taps, I don't know the proper designation as they are not NC or NF.

I have an early Investarms Hawken barrel and I could check the sight thread size later this evening for you if you like. I would think the earlier suggestion to call Dixons is the practical solution as you wont get those machine screws at the local hardware store. Thanks

 

[lonewolf5347]

I did install the Lyman Rear Peep
Also used a taller front fiber optic sight for old eyes.
Gun shot a great one hole group.
The Lyman rear peep a little harder then Thompson center peep to install.
All went well still looking for the filler screw size.

 

[Zonie]

Like OldRust says, the #6-48 thread size is not a standard thread combination. It is not a ANSI, ASME, Unified thread, Whitworth, or British Standard thread.

The thread charts that do show it say it is a NS thread so it is a National thread form for a 48 pitch thread. The "S" stands for "Special".

In my digging, I found a chart that shows it along with the recommended tap drill for it.
The tap drill is a #31 which is .1200 in diameter. It would be tempting to use a 1/8" (.1250) drill to prepare the hole but I wouldn't recommend doing that.
The thread height is only .011 tall so it needs all of the material it can get in the hole before tapping it. That extra .005 that a 1/8" drill would remove will weaken the thread considerably.

If you want a thread chart that lists the #6-48 along with a lot of other odd thread sizes along with the standard sizes, follow this link.

https://www.lincolnmachine.com/tap_drill_chart.html

To save it on a computer take a "Screen Shot" of it while it is on the screen by poking the PrtScn button. Then paste it into a photo, Crop the photo to get rid of the extra stuff that is outside the chart and save it as a jpg file.

I just did this after adjusting it down in file size for the web. You should be able to COPY it and save it in your computer for future use.

 

[bubba.50]

Not arguin’, startin’ a whizzin’ contest or even statin’ what is the correct size.

Barrel : Investarms 50cal

Screws : 6x48 finger tight.

 

[OldRust]

Not arguin’, startin’ a whizzin’ contest or even statin’ what is the correct size.

Barrel : Investarms 50cal

Screws : 6x48 finger tight.

Bubba I agree with your first line, we are all adults here and this is just a conversation.
I also have a spare early Investarms Hawken barrel. AH marked making it 1981 production. I assumed the threads in question would be metric but I ***-umed wrong. A 6-48 plug tap bottomed out with finger and thumb. Thread pitch gauge shows 48 tpi on the sights mounting screws. Attached photo shows 2 6-48 screws out of my spares also finger tight.

Lonewolf You have a 2 for 2 on the thread size If you are satisfied that's enough data just google Forster-plug-screws-6-48-x-1/8" blue Thanks

 

[SDSmlf]

Check the tread sizes for Pedersoli shotgun nipples or Uberti Walker nipples. Italian made so ‘must’ be metric, correct?