29 replies to this topic

[Phil Krankowski]

Threads are typically 1/4-28. Most inexpensive tap kits do not have this size. Take a tip and go buy the tap, it'll set you back $5 or so with the correct # drill at the big box store.

Phil

[Ferguson]

I went out and found my thread gauge, and it appeared to be 24 threads per inch, not the standard coarse thread, 1/4 - 20, or fine, 1/4 - 28. I will try to find a 1/4 - 24 tap.

If that does not work, it must be metric.

Thanks.

Richard

[Ferguson]

I went out and found my thread gauge, and it appeared to be 24 threads per inch, not the standard coarse thread, 1/4 - 20, or fine, 1/4 - 28. I will try to find a 1/4 - 24 tap. But when I looked in my Enco catalog, that was a 'special', $12 each, I doubt my local store has one. Maybe it is 12-24.

If that does not work, it must be metric.

Thanks.

Richard

[Mainely,Bob]

Richard,

If you are planning to make a trip out to get the tap I`d suggest taking the tip with you and going to a well stocked local fastener supply house that you can find thru the phone book.
Any good fastener shop can measure the threads(both SAE and metric) and then provide both the tap and the correct size tap drill.
While it may not be as cheap as Enco it`s alot better deal when you factor in the frustration of guessing and then receiving the wrong tap.
My closest fastener guy is a little over an hour away(Portland ME.)so I combine errands and maybe a little pleasure.Like going out to lunch with my wife down in the Old Port.

[Ferguson]

I visited the best hardware store that I know of, about 15 minutes from my house. They have a large fastener selection. We were unable to find a compatible nut. The pitch is 24 threads per inch; that is what I measured, and they confirmed it. We tried metric sizes, as well as #12-24. Nothing fit. I measured the OD of the threads with a digital caliper, and came up with 0.230 inches, a little less than 1/4 inch. The manager of the fastener department said that it had to be a special thread, and I am inclined to agree with him. He said that anything 1/4-24 was probably pre world war II, but that the railroads still used it because they have some lights that were made that way.

I may order a special tap, size 1/4-24, knowing that it will be a little large. It may not work too well, but maybe better than the 1/4-20 that I tapped the hole for the first time. (For quarter inch, the standard threads are UNF 1/4-28, and UNC 1/4-20.)

Richard

[Phil Krankowski]

I'd buy some new contact tips instead of ordering a special tap. Likely cost less. I am using some Lincoln Electric tips from Lowes, they have 1/4-28 threads.
Phil

[reefera4m]

Ferguson, on 01 February 2010 - 04:37 PM, said:

I visited the best hardware store that I know of, about 15 minutes from my house. They have a large fastener selection. We were unable to find a compatible nut. The pitch is 24 threads per inch; that is what I measured, and they confirmed it. We tried metric sizes, as well as #12-24. Nothing fit. I measured the OD of the threads with a digital caliper, and came up with 0.230 inches, a little less than 1/4 inch. The manager of the fastener department said that it had to be a special thread, and I am inclined to agree with him. He said that anything 1/4-24 was probably pre world war II, but that the railroads still used it because they have some lights that were made that way.

I may order a special tap, size 1/4-24, knowing that it will be a little large. It may not work too well, but maybe better than the 1/4-20 that I tapped the hole for the first time. (For quarter inch, the standard threads are UNF 1/4-28, and UNC 1/4-20.)

Richard

That's exactly the approach and outcome I got - it looked line 1/4" 24 thread. It turned out tips were indeed metric. 6mm to be exact which requires #5 drill bit.

[dragonflySmithy]

pkrankow, on 01 February 2010 - 04:43 PM, said:

I'd buy some new contact tips instead of ordering a special tap. Likely cost less. I am using some Lincoln Electric tips from Lowes, they have 1/4-28 threads.
Phil

I agree on the new tips and the other thing to do is to hit them with some solder to make sure it's sealed.

[territorialmillworks]

Lincoln tips are 1/4-28. I've run Tweco tapered tips side by side with straight tips and couldn't tell any difference. If you want, chuck a straight tip in a drill and run it against a flap sander = a Tweco tapered tips.

[Focalforge]

2 questions, What size bell reducer are you using? It should be a 2-3/4 with the tips. and did you solder/braze the joint between the pipe and tip?

Jamison