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Starrett 174 Tap Handle.. Need Internal Threads Please.

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woodchucker

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#1
Just picked up a 174 tap handle for $1. I believe the smallest handle they make. it was missing the threaded side of the handle. Can someone give me the size of the screw, and TPI please. Would like to make a new handle.
A pic would be great too, if you could.

Thanks
Jeff. SDC11748.JPG
 

4gsr

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#4
I'm sure it's a non-standard thread. Pull out your taps and start trying one's until you get one that starts in the thread. Don't force it! If it will not go all the way in. The trick to it is to get one to start that has the thread pitch that matches the closest. Since your going to make the missing handle, tap out the hole with the tap that fits the hole the best.
BTW- Push all your Metric taps the the side. Starrett does not use Metric threads in things like this. They will be Imperial thread pitches. Ken
 

Billh50

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#6
After posting I was putting the screw back in and noticed it had a bit of a wiggle going in. I would try a 1/4 - 28 allen screw and if it fits just turn the end down so that any mushrooming on end will still allow removing.
 

Billh50

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#7
Just tried a 1/4 - 28 screw as well as metrics. It is definitely one of the odd starret threads. I don't have wires to check the pitch diameter or I would do that for you also.
 

4gsr

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#8
Just tried a 1/4 - 28 screw as well as metrics. It is definitely one of the odd starret threads. I don't have wires to check the pitch diameter or I would do that for you also.
It won't be metric!!! But at .222" OD could have been 12-28 NF thread?
 

Billh50

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#9
A 12-28 has a max major of .215
So I really believe it to be one of Starret's own threads. Back in the day many of the machine manufacturers had their own threads. I remember re-tapping many holes for standard threads as I could not see paying $5 for one screw when I could buy a standard for $0.10
 

george wilson

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#10
Whittle a pencil down. Stick it in the hole and rub it on the threads. Then,check the pencil with a thread gage. Not hard to do.

If it's an odd thread,turn out the missing handle on your lathe. I have never NOT been able to make threaded parts to fit 18th. C. parts that were missing threaded pieces,even left handed.

Don't take the threaded part out of the chuck. repeatedly try screwing it into the hole and sneak up on it till it screws in. That is the simplest way to do the job rather than trying to figure out the actual diameter of the needed thread.
 

Billh50

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#11
The Starret 174 tap handle I have is definitely a .222 - 28 thread.
 

woodchucker

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#12
Drew this from my tap handle. Starret had it's own threads back in the day. So mine looks be an odd ball thread.
Yep, I concurr it's .222 -28 was about right, did a quick test out of alum before I use a piece of SS. I already knew it was an Odd ball size as nothing I had fit.
after reading about the wiggle I cut to .223 and then tested repeatedly instead of cutting deep. Then filed the tops of the threads down, fits nicely not too tight but no discernable wobble. I'll make one out of a piece of stainless I have.
Thanks for the drawing and details much better than a picture. :)
Thanks again.
 

scwhite

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#16
Yep, I concurr it's .222 -28 was about right, did a quick test out of alum before I use a piece of SS. I already knew it was an Odd ball size as nothing I had fit.
after reading about the wiggle I cut to .223 and then tested repeatedly instead of cutting deep. Then filed the tops of the threads down, fits nicely not too tight but no discernable wobble. I'll make one out of a piece of stainless I have.
Thanks for the drawing and details much better than a picture. :)
Thanks again.
That is a 12-28 thread
Number 12 bigger than a 10 smaller than a 1/4
My Cleveland twist Drill chart shows that tap
As a 12-28
 

scwhite

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#19
Yep, I concurr it's .222 -28 was about right, did a quick test out of alum before I use a piece of SS. I already knew it was an Odd ball size as nothing I had fit.
after reading about the wiggle I cut to .223 and then tested repeatedly instead of cutting deep. Then filed the tops of the threads down, fits nicely not too tight but no discernable wobble. I'll make one out of a piece of stainless I have.
Thanks for the drawing and details much better than a picture. :)
Thanks again.
Are 12-28 taps still made?
I would say yes but you are not going to find
One at Lowes or Home Depot - or Harbor freight
You will have to go to a machine tool supply
And order one
I would get all three if I was going to order them
Plug - through- and bottom
 
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