Thread: i thought i had a windfall but?

Is it a two start thread?

Meaning the thread is actually two threads running side by side.

rc i think your on the money with a closer look i can now see where the thread finishes the same at opposite sides

Just measure an inch and count how many threads,just by looking at it and compareing it to mine the pitch looks to fine .

definately 8tpi

Your easiest way to check would be to run the Tap through an existing Thread that suits your spindle.

If it passes through no problem if not its no good.

I'm with R.C
I reckon its a double start as well. The helix angle looks wrong for a single start.
Easy way to tell. if its a double start, the end of the each thread will be 180deg from the other one. Or get a felt marker and carefully mark the top of the thread for one full rev of the tap. If its single start then your mark will be on the next pitch from where you started. If its double start it will be the 2nd pitch away.
If it is a double start, then I reckon it would have been a pricey item when new as it more than likely was a custom one.
bollie7

thanks evry one for their in put yes its a 2 start tap it has 2 opposite start threads so in effect its 2 x 4tpi running side by side .........damn i now own a useless piece of hss
john

It only cost you $1.00 use it as a paper weight.

Originally Posted by tanii51

thanks evry one for their in put yes its a 2 start tap it has 2 opposite start threads so in effect its 2 x 4tpi running side by side .........damn i now own a useless piece of hss
john

Only if you can't think of a use for it. I can think of one straight up. Make yourself a couple of small screw jacks. You would have to screw cut the external thread which would be a great learning exercise and at the end you would have a very handly screw jack which can be very useful for setting up odd shaped things on mill tables etc. You could make a couple of different sized ones. If you are not sure of the type of thing I'm talking about, sing out and I can knock up a mudmap and scan for you. (won't be a cad drawing though)
bollie7