Drill & tap size for Johnson peep sight

[troy2000]

Does anyone know what size drill and tap to use for the screws that come with the Johnson peep sight?

 

[SDSmlf]

Does anyone know what size drill and tap to use for the screws that come with the Johnson peep sight?

If you can’t measure the screws yourself, best to ask the people that make and sell the Johnson peep sight. Specs could change over time.

 

[BS]

7/32 X 40 threads, try a search , I did!

 

[troy2000]

If you can’t measure the screws yourself, best to ask the people that make and sell the Johnson peep sight. Specs could change over time.

If they answer emails like they ship, I'll be waiting a while for an answer. But I'll give it a shot... I don't have any way of checking the threads on something that small.

 

[troy2000]

7/32 X 40 threads, try a search , I did!

Thanks... guess you're a better searcher than I am. I don't claim to be any internet maven.

 

[SDSmlf]

7/32 X 40 threads, try a search , I did!

Hard to believe they are using old fractional sized threads, but if they, a new tap will be pricy for what it is. Believe a 12-40 tap is only .003” smaller diameter and much more common and possibly what was used. My reason for suggesting OP ask Johnson.

 

[BS]

7/32 X 40 is a standard peep size.

 

[SDSmlf]

7/32 X 40 is a standard peep size.

And I have found the 12-40 tap to work just fine for 7/32-40 peep sights. Have seen booth threads used interchangeably by sight makers.

 

[Pete G]

That is the aperture, not the base.

 

[rdane]

Find a hardware store that has gun screws. They will have a gage to check the threads.

 

[troy2000]

That is the aperture, not the base.

Yep, you're right. I wasn't thinking; 7/32 is way too big for the mounting screws, which are what I need to drill and tap for.

 

[troy2000]

Find a hardware store that has gun screws. They will have a gage to check the threads.

I'm in a town in the middle of the desert right now, with exactly one Ace hardware store, and I seriously doubt they sell gun screws.

 

[troy2000]

Found it; the mounting screws are 6-48, and need a nr. 31 drill bit. And of course, all Ace had was a 6-32 tap...

 

[BS]

Sorry, did not really read......most folks need to know the Peep thread. Glad that you found the "Mounting Screw size".

Many place to order them from, but Brownell's usually has fast service.

Buy two.

 

[troy2000]

Found it the mounting screws are 6-48.

 

[SDSmlf]

Yep, you're right. I wasn't thinking; 7/32 is way too big for the mounting screws, which are what I need to drill and tap for.

Wasn’t thinking when I responded about the 7/32-40 vs the 12-40. Thought BS was commenting from actual first hand experience with the Johnson sight. My bad.

 

[oldwood]

Wherever you buy the screws , buy the starter and finish tap as well. Short holes that sight screws go in , require a way to tap to the bottom of the hole.

 

[troy2000]

Wherever you buy the screws , buy the starter and finish tap as well. Short holes that sight screws go in , require a way to tap to the bottom of the hole.

I already have the screws; they came with the sight. Kind of embarrassing to admit, but when I went back to the vendor the description of the sight actually said it came with 6-48 mounting screws; I guess that didn't sink in when I made the order. At this rate, pretty soon I'm going to need to hire a little boy to keep track of me, and make sure I remember to zip my pants and put my shoes on the right feet...

I ordered a cheap three-tap set, and a good quality bottom tap. Hopefully the cheapos will last long enough to get the threads started, and the good bottom tap can finish them.

 

[troy2000]

This Johnson peep sight is going on my Kibler SMR. This morning I was reading some old threads on peep sights, and where to mount them. Most people mount them on the barrel, although one old boy chimed in that doing so instead of mounting them all the way back on the tang made them as useless at teats on a boar hog. That fact that multiple other posters said they'd been doing it for years and were perfectly happy with the results didn't change his mind one iota....

I temporarily fastened mine as far back on the barrel as possible with masking tape, and was pleased with the sight picture I got. Much better than the traditional notched rear sight. That put it beside the lock, which seems to worry some people, because of it getting fouled and dirty while shooting. But I don't shoot so often that I can't clean it off now and then...

Planning on taking the rifle out tomorrow morning with the sight taped on, and giving it a try. Looks to me like centering the top of the front sight in the aperture is going to make it shoot pretty high. If it does, I'll deal with it one way or another. I might bend the base a little and move it back partway onto the tang, or get a taller front sight, or...

 

[troy2000]

For those not familiar with Johnson peep sights, here's a pic of one from another thread. It's in German silver, as is the one I bought. The owner said it's brass, but I think it might be a very yellow German silver like mine. I'd rather have had one in iron, which would be more in keeping with the steel furniture on my gun, but they were out of stock. This one's on a jaeger if I remember right; the thread is here: Johnson Peep Sight