How to make a tap, to make a tool, to fix a Sheridan

I had an interesting project come my way to repair a Sheridan. It became such an epic that this thread could be called "The winding road that never ends"

Quandry #1....What the H$!! is it? No model numbers no serial numbers. "Sheridan Products, Racine Wisconsin" But based on the rocker safety and the lack of any markings or serial number it was made somewhere between 1963 and 1970...Even no information can be useful at times.

But that means it's one of the infamous Sheridans with the soldered in valve, lead seals and a whole heap of misery. :icon_frown: I've heard about these but I've never had to deal with one.

Quandry #2 How the H$!! do you get it apart?

Well it turns out that you need a double ended tool to first undo an internal cap nut then the other end of the tool screws on a 9/32"- 32tpi thread to use as a puller bar to jerk the valve core free of the two lead seals holding it in.

Well first thing you find out that all the original sellers of this beastie have disappeared.....except of course for Pyramid Air....So unobtainium. Second thing you find out is that because of the 9/32-32 threads no one has actually made this tool as it is supposed to be and published the information. So the purpose of this thread is to get that information published.

Seriously Sheridan 9/32" 32tpi....Was it really necessary to invent your own thread:chargrined:

The project starts with a piece 3/8" round bar at least 6" long. I used a 1/2 bar 12" long and turned the ends to 3/8. This way I could put a single hole in the center of the bar.

The square drive to remove the cap nut is relatively simple and has been publish here and there with varying degrees of accuracy.

Square drive end
Starting from 3/8 round stock mill or file a square that measures .350 across the faces. The corners will be left round at this point and they need to remain round.
Drill a 9/32" (.281) hole into the end of the bar that is 3/4" deep.
The wall thickness is only .034" so use alloy bar and harden the working area

What a wonderful learning experience! :friendly_wink:

I know, I'll shaddup now.

Haha...I don't necessarily blame you for this but there is association. :icon_razz:

Sorry about the delay I get this thread moving along again. Obviously a 9/32" -32 tap is not a readily available size and you need one to make this tool. Either that or your a threading genius that can single point internal threads in a 1/4" hole.

Next thing was to do the thread calculations for a 9/32-32 tap
For anyone interested here they are
Major dia 0.281"
Minor dia 0.246"
Basic height 0.019"
Tap drill (75%) 0.250"
Compound infeed (29.5*)0.023"

With the calculations finished all that's required is to turn down a piece of tool steel to the major dia (plus .001-.002) The plus is for deflection of the work during tapping.
Put a 5 to 7* lead in angle. Just like a taper tap
Then thread it per the calculations

Tool steel always threads best when you are running as close to the rated SFM as possible. Ie the thread chase is whipping around like a ferrari....but you get a nice thread.

I think I'm getting the idea why Sheridan went out of business/got bought out 20 years ago...

Quote:

---

Originally Posted by AirGunEric

I think I'm getting the idea why Sheridan went out of business/got bought out 20 years ago...

---

Haha...That's funny I was thing exactly the same thing...." No wonder you stupid a$$es got sold"

Hi Sean. I don't know if Victor Machinery ships to Canada , but they sell 9/32 -32 taps for $9.50 . They are half way down the page.http://www.victornet.com/subdepartme...inch/1260.html

OH!.... I can hear him growling now!.....

Bob

Ya that's that's a bit of a pi$$er. Still would have been a toss up to do a shop made tap though as it's a one time only use item....at least I don't have any plans to do a lot of 9/32 tapping.

But thanks for the link....that looks to be a good resource and the pricing is very good.

What's more of a PITA though is 3/4 of my last post seems to have disappeared.....wth happened there I wonder.