Handbrake button thread size?
Discussion
Hi Mags.
As most cars of that era were using Unified threads it’s more likely to be 10-32 UN.
The dia is 4.82 mm and the pitch is 0.793 mm, M5 is 0.8. Also the thread angle is 60 deg for both. So very close.
If it were me and I didn’t have a 10-32 tap I’d use M5 but it’s your car so your choice.
Hope this helps.
As most cars of that era were using Unified threads it’s more likely to be 10-32 UN.
The dia is 4.82 mm and the pitch is 0.793 mm, M5 is 0.8. Also the thread angle is 60 deg for both. So very close.
If it were me and I didn’t have a 10-32 tap I’d use M5 but it’s your car so your choice.
Hope this helps.
Griffo400 said:
Hi Mags.
As most cars of that era were using Unified threads it’s more likely to be 10-32 UN.
The dia is 4.82 mm and the pitch is 0.793 mm, M5 is 0.8. Also the thread angle is 60 deg for both. So very close.
If it were me and I didn’t have a 10-32 tap I’d use M5 but it’s your car so your choice.
Hope this helps.
Thanks, that makes sense, would be good to know for sure, maybe I can look on ebay for a nut in this size to try.As most cars of that era were using Unified threads it’s more likely to be 10-32 UN.
The dia is 4.82 mm and the pitch is 0.793 mm, M5 is 0.8. Also the thread angle is 60 deg for both. So very close.
If it were me and I didn’t have a 10-32 tap I’d use M5 but it’s your car so your choice.
Hope this helps.
Mark
Hi Mags
Going back to the UN range it’s probably 8-36 UNF.
Looking at online thread table ( haven’t got my Zeus book or Machinery’s to hand ) the bottom limit for 8-36 is 4mm as near as damn it.
As these were made by the million the thread would have been made small to allow for any plating and easy assembly.
The pitch for M4 is 0.7. Dividing 25.4 by 0.7 = 36.285 TPI with a 60 deg thread angle so once again very close.
As I said previously if you haven’t a 8-36 tap use an M4 and to be honest it will probably be a better fit.
If your worried about originality, shhhhh, I won’t tell anybody if you won’t,
Brian
Going back to the UN range it’s probably 8-36 UNF.
Looking at online thread table ( haven’t got my Zeus book or Machinery’s to hand ) the bottom limit for 8-36 is 4mm as near as damn it.
As these were made by the million the thread would have been made small to allow for any plating and easy assembly.
The pitch for M4 is 0.7. Dividing 25.4 by 0.7 = 36.285 TPI with a 60 deg thread angle so once again very close.
As I said previously if you haven’t a 8-36 tap use an M4 and to be honest it will probably be a better fit.
If your worried about originality, shhhhh, I won’t tell anybody if you won’t,
Brian
Griffo400 said:
Hi Mags
Going back to the UN range it’s probably 8-36 UNF.
Looking at online thread table ( haven’t got my Zeus book or Machinery’s to hand ) the bottom limit for 8-36 is 4mm as near as damn it.
As these were made by the million the thread would have been made small to allow for any plating and easy assembly.
The pitch for M4 is 0.7. Dividing 25.4 by 0.7 = 36.285 TPI with a 60 deg thread angle so once again very close.
As I said previously if you haven’t a 8-36 tap use an M4 and to be honest it will probably be a better fit.
If your worried about originality, shhhhh, I won’t tell anybody if you won’t,
Brian
Thanks Brian, I'll give this a go. The new button that I bought is no use and funny enough isn't threaded, it's just soft plastic inside so it self cut's as you wind it on.Going back to the UN range it’s probably 8-36 UNF.
Looking at online thread table ( haven’t got my Zeus book or Machinery’s to hand ) the bottom limit for 8-36 is 4mm as near as damn it.
As these were made by the million the thread would have been made small to allow for any plating and easy assembly.
The pitch for M4 is 0.7. Dividing 25.4 by 0.7 = 36.285 TPI with a 60 deg thread angle so once again very close.
As I said previously if you haven’t a 8-36 tap use an M4 and to be honest it will probably be a better fit.
If your worried about originality, shhhhh, I won’t tell anybody if you won’t,
Brian
I will take a couple of pic's as it feels this if becoming a bit over complicated!
Mags said:
RobXjcoupe said:
If you are making your own, just change the thread and nut to metric.
That might be helpful, what's the threaded bar connected to? Is this covered in a manual somewhere, it's not in the Steve Heath bible.Thanks
Mags
RobXjcoupe said:
Mags said:
RobXjcoupe said:
If you are making your own, just change the thread and nut to metric.
That might be helpful, what's the threaded bar connected to? Is this covered in a manual somewhere, it's not in the Steve Heath bible.Thanks
Mags
I'm not surprised there seems to be different threads as the whole handle has been shortened by TVR and re-welded. As a result the rod will also have been cut short and re-threaded. One guy had a metric tap & die set the older guy had imperial.
Steve
OK, will see if these photo's help.
There are two buttons shown, the one that is uniform diameter is the new one and doesn't work on my handbrake. I can screw the button on the thread but as it doesn't fit inside the black metal handbrake it doesn't allow you to disengage the brake.
The one with the wasted end slides down into the black handbrake to allow you to disengage.
The threaded bar is 3.94mm diameter, the other measurements are in the pictures.
A couple of 4BA nuts turned up today so will try that tonight if I can, if not will try 8-36 UNF. 4mm goes on a turn or so and then binds, I don't want to chew the thread.
There are two buttons shown, the one that is uniform diameter is the new one and doesn't work on my handbrake. I can screw the button on the thread but as it doesn't fit inside the black metal handbrake it doesn't allow you to disengage the brake.
The one with the wasted end slides down into the black handbrake to allow you to disengage.
The threaded bar is 3.94mm diameter, the other measurements are in the pictures.
A couple of 4BA nuts turned up today so will try that tonight if I can, if not will try 8-36 UNF. 4mm goes on a turn or so and then binds, I don't want to chew the thread.
Edited by Mags on Tuesday 7th September 18:02
The new button is 14.97 but the 16mm hole of the ally grip is just cosmetic, it slides over the black lever. I didn't measure the ID of the black lever which is where the 12.5 end of the broken button slides into to release the ratchet mechanism.
My brother in law can machine me the button once I know the thread.
My brother in law can machine me the button once I know the thread.
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