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MG MG Y Type - Jackall tube nuts.

Having studied the archives, as far as I can see most recent opinion (in 2017) was that the tube nuts are UNF, which surprises me. The 7/16 x 24 (1/4 inch internal) are referred to as UNF with a 55 degree pitch. There are references to BSP and BSB, but these seem to have been discounted. Is there a definitive statement anywhere? - I'm looking at trying to find new 7/16 and 5/16 in the 1/4 id as well as the 1/2 inch in the 5/16 id. Tony S has offered me 2nd hand, which is great - but I'd still consider new "down the track".
Thanks for any confirmation of the thread detail.
John.
J P Hall

John,
Have you taken the jackall ram parts to a hydraulic pipe specialist to get them to check thread size etc?

I have found the smaller/ independent businesses have a better selection of pipe fittings.

If chasing jackall pipe, check with air conditioning installers for old pipe imperial size pipe.

cheers
Stuart
Stuart Duncan

Stuart, yes I have - with no definite finding so far. 24 tpi Whitworth is the closest it seems. I have enquiries lodged with Neil Cairns and with NTG, so here's hoping!
Yours,
John.
J P Hall

Enzed would have them

Also, beware-
With the 7/16 unf nuts
3/8 unf is 24tpi
7/16 unf is 20--but for some weird reason they also do 24tpi unf in tubing fittings so check and make sure you're getting 7/16-24tpi and not 20

willy
William Revit

Thanks Willy - good info as always from you. I'll post any findings of interest. John.
J P Hall

John, The MGCC Y Reg had all the correct tube nuts in their shop but had to sell their stock to The Octagon as they were deemed a safety item and not insured. Although they are not listed on the Octagon parts list they should still have some. We had a batch of 50 1/4" 24tpi unf manufactured for us. The other sizes are available. From https://automec.co.uk/
Peter Vielvoye

To clarify our stock was
7/16" x 24 UNF for 1/4" pipe. (HU77)
1/2" x 24 UNF for 1/4" pipe. (HU89A)
1/2" x 24 UNF for 5/16 pipe. (HU89)
Peter Vielvoye

Thank you Peter for popping up - I have always read your contributions with interest. I could not find any table with 24TPI UNF in either 7/16 or 1/2 inch diameter - 20 tpi seemed to be standard at those diameters. Did the Y Register have someting extra fine made up, along the lines of UNEF?
My concern is (a) to have some certainty regarding the thread on the original Jackall fittings, and (b) to source new tube nuts knowing that they will fit!
Thank you also for the pointer to Octagon and Automec.
Yours,
John.
J P Hall

Willy Revit, you're spot on as always - I'm in Brisbane this week, and Enzed here supplied (off the shelf) the 7/16 tube nut at $4 a nut! They say it's for their range of brake fittings - worth noting for anyone in Australia, as only some Enzed outlets keep them. I got lucky.
Question: my fittings at the top of each jack (ram) are a 1/2" tube nut into the elbow. NTG refer to the jack fittings as 5/16, which I believe is wrong. I have taken this up with Paul at NTG - can anyone else confirm that their "jack top" tube nuts are 1/2" not 5/16" diameter? I know it's 24 TPI. I may try to source new replacements - Tony Slattery is helping me out with 2nd hand ones in the meantime.
Thanks for any advice.
John.
J P Hall

To clarify, so I don't confuse other restorers: In my original post I said that I was looking for "new 7/16 and 5/16" nuts in the 1/4" i.d. - WRONG of course - there is no 5/16" thread used in the Jackall tube nuts on the Y Type. Only 7/16 with 1/4" hole, 1/2 with 1/4" hole, and 1/2" with 5/16" hole (the latter from reservoir to pump).

Paul Banyard, who's been with NTG for as long as I can remember, has provided advice regarding the threads on the Jackall tube nuts sold by NTG. In essence, Paul says the 55 degree pitch angle means that the thread on their product is technically "Whitworth Form", (which apparently includes BSF and BSW); and that it is not strictly UNF, since that would have a 60 degree pitch. However, Paul adds "it could be either as so close". In NTG's opinion, the thread on their product is "Whitform", but "as it's brass, either will suffice".

NTG's website had carried incorrect size references (my excuse for being confused earlier), but Paul has already corrected those. Thank you NTG for clarifying - and for "Being There" for us.

I look forward to buttoning up the Jackall system and testing it very soon.
John.

J P Hall

This thread was discussed between 08/12/2021 and 23/01/2022

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