Odd Thread Size

[Chris GoodwillParticipant @chrisgoodwill78822]

Hi

I was Given an old record vice last year and have just got around to looking at it. After drilling out the sloted countersunk screws that hold the jaws on, I am having trouble identifying the thread. They could be a metric M8 x 1 fine thread or a 5/16 26tpi. The only other bolt on it is a 5/16 BSW.

I have tried looking up 5/16 26tpi but this seems to refer to a bicycle thread. Anyone know what size these screw are suppose to be?

[Chris GoodwillParticipant @chrisgoodwill78822]

[noel shelleyParticipant @noelshelley55608]

If it's an old record it will be BSW 5/16" bsw is 18tpi. 26tpi can be cycle or brass, whit form and ANY dia ! 1/4"BSF is also 26tpi. Good luck. Noel.

[Chris GoodwillParticipant @chrisgoodwill78822]

Just to add this bolt is 7.7mm dia and with my pitch gauge is ithere 26 tpi or 1 mm.

I think i will thread a piece of bar M8 X 1 and see if it fits.

[old martParticipant @oldmart]

I would plump for the 5/16 x 26. When I bought the present house, there was a poor looking old vise in the garage. It turned out to be a 5" Record steel bodied model. The jaws were scrap and I had great difficulty getting the screws undone and the threads were 5/16 26 BSC. I made some new jaws and got a couple of suitable screws on ebay, cleaned up the leadscrew and the jaws are parallel to within 0.002". That makes up for my mistake in leaving my 4 1/2" Paramo behind when I sold my bungalow.

[peak4Participant @peak4]

It would seem that Record used 5/16" BSC on some vices, as The Viceworks makes them specially , but make sure you pick the correct countersink angle.
https://www.viceworks.co.uk/products/vice-jaw-screws-and-bolts?variant=44213941076134

Bill

Edited By peak4 on 25/06/2023 20:00:17

[FulmenParticipant @fulmen]

What do you mean by "old"? I could imagine a true Briton chewing on broken glass before using a metric thread to this very day Or have you guys conceded that fight yet? It's a very nice system once you get to know it.

Besides nobody uses anything other than metric coarse (M8x1,25) unless they really have to.

[Chris GoodwillParticipant @chrisgoodwill78822]

Thank you everyone

The vice is an old record 34 steel and I did wonder about the countersinks as the holes looked a bit odd, been 60 Deg makes a lot more sense

[peak4Participant @peak4]

Posted by Chris Goodwill on 25/06/2023 20:17:46:

Thank you everyone

The vice is an old record 34 steel and I did wonder about the countersinks as the holes looked a bit odd, been 60 Deg makes a lot more sense

According to the website, the 60° angle was used on 34/35/36 vices.

Bill

[Neil LickfoldParticipant @neillickfold44316]

I have recently done up an old Record vice. The thread is 60 deg 5/16×26 TPI. I found Tap that suited , and cleaned up the damaged threads with that tap. It was available here in NZ. it was called a Bicycle 5/16-26 tpi, different to the Brass being 55 deg pitch angle.

I made the screws from long M8 capscrews. Cut the M8 thread off, trued the head diameters to the shank. Put in a small centre, and then held onto them from the head and a steady, and screw cut with a 26 tpi partial form 60 deg threading insert, until the diameter of the thread outer diameter was 8.87mm diameter.

I couterbored the existing jaws, so the normal caphead screws would fit. I plan on makeing other jaw sets for this vice, so using a ball end hex key makes them easy to install..

Neil

[Trevor Drabble 1Participant @trevordrabble1]

Chris , Maybe worth having a word with Wilkes Engineering and Machinery, also know as The Vice Works . They manufacture replacement jaws for a number of British vices , so perhaps could supply you with the correct screws. Trevor .

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