What would you think this thread is UNC or whitworth?

[TorontoBuilder]

I have a Dickson S1 Tool Post circa 1967

The bolt for the block appears to be 5/8-11 tpi with a major diameter of 0.612 and minor diameter of 0.524, below is a pic. The bolt is Colchester part number 24834-0. I just can't tell if this is UNC or whitworth thread. The nut for this is a replacement nyloc 5/8-11 so I can't tell if it is loose fitting, and I dont have a 5/8 nut handy.

So poll, do you think this is whitworth or UNC?

 

[twhite]

Now would be a perfect time to get a thread gage. Seriously though l, looking at your picture it looks to be UNC. By chance do you have a 5/8 bolt to use as a check? That will tell in a hurry.

If that bolt is anywhere serviceable. Put it back together and turn up what you need. Just a thought.


Cutting oil is my blood.

 

[TorontoBuilder]

I need to make a new locking lever instead of a nut... and I don't want it to be loose. So do I need to buy a whitworth tap

 

[TorontoBuilder]

Now would be a perfect time to get a thread gage. Seriously though l, looking at your picture it looks to be UNC. By chance do you have a 5/8 bolt to use as a check? That will tell in a hurry.

If that bolt is anywhere serviceable. Put it back together and turn up what you need. Just a thought.


Cutting oil is my blood.

I've scrounged around the house and no 5/8ths nuts around. Plenty in the shop along with the thread gauges, 1/2 hour drive away.

I'm not very patient or I'd wait til tomorrow to find out

 

[twhite]

I've scrounged around the house and no 5/8ths nuts around. Plenty in the shop along with the thread gauges, 1/2 hour drive away.

I'm not very patient or I'd wait til tomorrow to find out

Cutting oil is my blood.

 

[twhite]

Ok I just went out and did an overlay of a 11 UNC thread gage to your photo. I will say that it is UNC not Whitworth.


Cutting oil is my blood.

 

[RandyWilson]

The thread form looks Whitworth to me. Or very worn. UNC is 60 degree, Whitworth is 55. Stick a 60 degree threading tool into the unworn threads on the end and hold it to the light.

 

[twhite]

Oh this suspense is going to kill me. Now what are you going to do. 2 different opinions. Maybe you should just wait until tomorrow and measure when you get to the shop. Please let us know. This is fun. Is you might guess I am easily amused.


Cutting oil is my blood.

 

[TorontoBuilder]

Oh this suspense is going to kill me. Now what are you going to do. 2 different opinions. Maybe you should just wait until tomorrow and measure when you get to the shop. Please let us know. This is fun. Is you might guess I am easily amused.


Cutting oil is my blood.

I had been wavering between whitworth and UNC, they look 60 deg but slightly rounded thread form...

 

[Beckerkumm]

1967 is about the time of switchover. If you have the smaller bolts from the Dickson tool holder you can try a UNC in it or a nut for the bolt. BSW threads all have the same pitch as UNC except 1/2" which is 12 rather than 13. I'm betting BSW but the timing is close. Dave