11x36 tap
- Thread starter rimfire458
- Start date
Sure it was 36 and not 35 1/2?
I know that they used 35 and a half threads per inch on the High Wall/Low Wall 1885 rifles, per some of the drawings found at the Cody collection.
In any case, there are a number of outfits that will make taps and dies in about any combination of thread diameter/pitch/thread form, that the customer is willing to pay for.
Oh yeah. Picky details, but lest you really end up with the wrong diameter tap, refer to it as a "Number 11 by 36tpi" tap, as an 11 tap is likely to be read as 11mm. That would be bad!
Cheers
Trev
Well, you know that it makes little difference over 1". I rather think that the old machinist, who invented that thread size, was aiming for 36 threads per inch, but, the change gears on his old lathe were slightly worn and it turned out to be 35 1/2 threads per inch and this size was excepted as the standard....;-)
Y'know, lots of guys thought that was the case, until the drawings surfaced that said 35 and 1/2 on them!
The joy of gun screws as well as sewing machine parts! When you make stuff in house, you can make them to whatever standard you want!
Cheers
Trev
The original wood screw size was gauge number 11 with a body diameter of .203" and with 12 threads per inch. It would have been a natural progression to make the machine screw size, gauge number 11 with a .203" diameter body and 36 threads per inch. I still think that the drawing you speak of came after the prototype design.
- Location
- pallisers triangle
if your really lost for it, and need a guy who actually MAY have it in stock, and if not can get it, call MacDougal tool supply { 403-291-2970} in Calgary it is un believable what he has, ive yet to stump him. admittedly this is a weird one however.
Dunno. Campbell published it in one of his books on the Single Shot, along with what few other 1885 specific drawings survived the purge and long enough after, so as to arrive at Cody. It sticks in my mind, particularly because he mentions that folks had been calling them 35 or 36TPI screws for years, yet here was in his eyes, definitive proof, that that was not the case, at least proven for this one in particular.
Not hard to do. work out a gear train to cut 70 tpi, then swap out one of the ratio sets for one that is half the ratio (twice? I'd have to sit and actually scratch it out...). Even easier if using cam operated turrets or screw machines, as were pretty common enough.
Keeps the punters from going elsewhere for their spare parts too!
Cheers
Trev
Are you sure it is 11MM and not 7/16" ?
I sell a kit that raises the seats up in Jeep TJ's.
The inside rear seat hold down bolt that also holds the seat belt anchor is 7/16-20 thread. The other 3 bolts are 8 x1.25mm
I have had many people ask me where to get the 11MM bolts? as they figure they should all be metric. They aren't and I would suspect that your thread is not either.
11MM is .433" 7/16 is .437" that's is .004 difference? What do you think now? 7/16-36 or 11MM-36 TPI?
Been doing this for a while,,, I have owned a machine shop for 30 years, and I never seen an 11MM thread in use anywhere. There is no reason for it as there are 10mm and 12 mm threads in various pitches, and only .040 difference in diameters either way.
Randy
I sell a kit that raises the seats up in Jeep TJ's.
The inside rear seat hold down bolt that also holds the seat belt anchor is 7/16-20 thread. The other 3 bolts are 8 x1.25mm
I have had many people ask me where to get the 11MM bolts? as they figure they should all be metric. They aren't and I would suspect that your thread is not either.
11MM is .433" 7/16 is .437" that's is .004 difference? What do you think now? 7/16-36 or 11MM-36 TPI?
Been doing this for a while,,, I have owned a machine shop for 30 years, and I never seen an 11MM thread in use anywhere. There is no reason for it as there are 10mm and 12 mm threads in various pitches, and only .040 difference in diameters either way.
Randy
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Go back a re-read the posts Randy!
It's not about a metric tap, but a number size one. But thanks for proving the point I made in post number 7.
Cheers
Trev
