wtb: special tap

Maybe a slightly different approach? What if the original part were redesigned to accept a brazed-in tire valve? You can get a set of 4 all-metal tire valves from Pep Boys for under $10, or could about 3 years ago anyway. Those of course have the threads already in them.

Alternatively, you could try making a one-off tap.

Grant

"Jon" wrote: (clip) a hole (clip) a short run job (clip) ^^^^^^^^^^^^^^^^^^ One or several? If it's only one or two, have you thought of inserting the end of a valve stem (silver solder or epoxy)?

No options here, I need the tap, but thanks for the suggestion.

Are you sure there are no options?

Schrader valve stems are sometime threaded *outside* as well - don't know the thread, but it may be a more common one.

Drill & thread that hole, insert & loctite a valve stem.

I have a customer supplied design to follow. No options.

Thanks!

"Jon" fired this volley in news:tPLij.8816$W73.3610@trnddc04:

Jon,

I went through the same folly-worn path on a project in my shop. Schrader wanted something like $80 for the tap, with a five week waiting perior.

I ended up finding the best quality "tire valve tool" I could find, and hardened the internal thread chaser. With that, and a bit of care, I was able to tap the six holes I had to make for Schrader inserts.

If I were to do it again, I'd just fabricate the tap from some good air- hardening stock, and be done with it for the foreseeable future.

LLoyd

Doing some Google searching, I found this link.

Or in looking up the price $1.25

Wayne D.

I don't know if this site is selling a tap:

I didn't do very well looking for you but I did try.

It looks like threading a piece of A2, grinding flutes and hardening is the way to go atm.

And I thought the 7/32-40 irrc, tap for rear sight aperature inserts was an oddball!

Wes

Cx??UÛnÛ8}×WÌ?\G²ã4»M?n³©?è6?d//
-Q?TI*ªúõ{?r?ØE?FHj8sæÌÌaí|mñ·tÂv*ÿ"­Z??¯«>5.NM½SàCg?¤4ÕÒ9QH?´ìÜÉdjtÝM]ñ»{6}Û?m¤åÏ|;?ãè¥z?A>}/ZaU]_Õ"-??¯o¤U??µôwaO^&ê??ûkþÍwk?Ò úbV?*-É?­²Ò
.yC^4ø\?*¤ÐXÙPn,?\ZZ?IKÛnoDu#·??·/J?(­?D ??Á èrí{×Q'WNy9"å?h? ¦?QÛ.{?þiã ´ÖFW=?¡*±BZ¹559oÒë?ÎéZ??§9¥B?kdªDE??ÔýÚû?V­''eíþJL[­eÊ%·ý¶_ù­?ÚÉ[&Kc=ÙVs?Jh?Ãwo´¤R8^??C:9À?§?UF?º%t²ªF@?ql/¶½:ÓÚ$7?ð?íEêÑOÁAL}?Bß>fr ?3£wý??Ê?¹¸??Ê?`}£¹©ô¾9I?®ëâZ¨? ª¿%5Y?ú+¥s7es{à®T?L'Ï.AÒÍe?É49>BË1??yîMKÂJª?¹fD(åzº­W®ýÞ6Âú0äÉáx|?L?çÉÅrüü`rxü_??è?Ò×?§³ó?è?N?3ZÌÞ.æïh9[\ÒåÇ?ù§³KZ~^Ì?½Û?ýsFçÃúú?÷oö÷>?..6¦?Îßnl§ÓýÇ?2®Of??^CIî³?áq?äm?ì??n?A ?ò6 ³ízz8"ç9ôUr×gè~L æCTdÃ)&`c??§ 0$|ý0?S8ã²i?2?ý?L??¬MGAD8=`´èG6ká[ËÒè$ê?X[`ÄFã???¨ª_D÷$ì£r0âë ¥B"Ú"uÐë~4(W7?S Xq±¤Ît
Ï
????ñw?½. ÉslXåqÇ4^?¯?/²ÂD!>×qô^ÒJ8?}ON(&«D7â9Giëýz:r¦=W]7?/h¯®?(

I think the relief valve in Bernz-o-matic cyinders is the same construction and thread. You might try approaching it from that direction.

Did a bit of googling and found this response in a similar thread:

"We carry these as specials. Normal delivery is just one day. They are not on our website, but if you go to

url is

Suggest you make the special. Take a split die of -36tpi that is close and compress or expand and see if the .206 will fit - might be able.

Mart> I'm doing a job which requires me to tap a hole in prep for a schrader valve > core.

Even if you get the hole tapped, there's the gently tapered seat for the bottom of the schrader valve to be reamed out. Jerry

Get a threaded tire valve stem and thread the hole to take the stem.

That sounds cool. How do you make a tap in the home shop?

Chris

Any time I need an adapter with a tire valve connection, I take an old valve stem that the tire shop replaces every time they mount a tire, cut the rubber off, wire brush it clean and silver solder it into a quarter inch hole in whatever fitting I am adapting to. No cost except for heat and a bit of silver solder.

Gerry :-)} London, Canada

I may be doing it the wrong and/or hard way but, I've done it a couple of times. Once when I had a die of the right size but not a tap - used it to thread some rod, then just ground out some relief cuts on the rod to make a tap-shaped object. Very freehand and very much not optimal angles for anything but, it made the cut I needed for exactly one hole. Second one was a bit more ambitious, single-pointed a threaded rod on the lathe and again hand-cut 2 relief cuts. Made the hole I needed. Probably not the right way but, for this job, was fine. (metric left-hand thread for one-time use, don't ask).

Did you have to heat treat or case harden it? Or were you only tapping brass?

Best wishes,

Chris

(snip)

Once aluminum, once mystery-steel for a nut that was expected to have about 3 uses ever. Lots of lube and it came out OK but I wouldn't suggest it for a "real" project. This was for a water-pump tool for Triumph/Saab inline-4 engines, and several hand-turned uses per year are to be expected, kind of a gear puller with a threaded end rather than a point. If it was anything that'd deal with any number of cuts, I probably would have just bought the oddball tap. But for a one-off of not-rocket-science dirty hack spec, it was good enough. (I never claimed to be a machinist, I'm just a guy with machine tools in the basement).