Last visit was: Thu Oct 29, 2020 6:44 pm It is currently Thu Oct 29, 2020 6:44 pm

All times are UTC+01:00




 [ 5 posts ] 
Author Message
PostPosted: Wed Oct 28, 2020 3:45 pm 
Offline
User avatar

Joined: Fri May 22, 2009 6:43 pm
Posts: 2763
Current ride: S1`s
Location: Llanelli South Wales
Need to repair the rear brake cylinders on my old landrover which has ali slave cylinders .

Does any one know the Tap thread size you cut to take the 7/16" - 20- unf wire insert ?

Also to take the 3/8" - 24 - unf wire insert ?

Trying to save them for spares, but the insert kits are expensive. Can buy the inserts loose if I know tap size .
Thanks.


Top
   
 
PostPosted: Wed Oct 28, 2020 6:01 pm 
Offline
User avatar

Joined: Fri May 08, 2009 7:54 pm
Posts: 2477
Current ride: 1999 X1
Location: Texas, Gerrards Cross
If we're talking about heli-coils, the taps are not standard sizes. They are special because the inserts are coiled wire of a given dimensional cross-section, so the nominal OD of the tap doesn't correlate to anything standard. So when looking for a tap for heli-coils, you have to buy one that is "designed for" whatever insert you want. If you can extrapolate any information out of a heli-coil insert, it is that the the tap for it will be the same thread pitch as what you are trying to match, in your case 20 TPI. But you can't determine the OD.

So, yes, they are expensive. You need the tap, installation tool and the insert. I believe you also need a way to break off the nib that allows you to screw it in, so that means another tool.

You might just want to take it to a machine shop or simply tap to the next size up if there's enough meat to work with. To me, heli-coils aren't worth the trouble.

There's also a cheaper alternative. Look here: https://www.mcmaster.com/threaded-inserts/black-phosphate-steel-easy-to-install-thread-locking-inserts/system-of-measurement~inch/thread-size~7-16-20/

This solution does take a standard tap. And doesn't consume any more meat than a heli-coil. I prefer these over coiled wire any day because it's one piece. I probably should have just led off with this one.

_________________
Bob Krzeszkiewicz
2012 XR1200X - 2011 Kawasaki Z1000SX - 1999 Buell X1


Top
   
 
PostPosted: Wed Oct 28, 2020 8:00 pm 
Offline
User avatar

Joined: Fri May 22, 2009 6:43 pm
Posts: 2763
Current ride: S1`s
Location: Llanelli South Wales
Yea , thanks . looked at 3/8 unc set I`ve got and noticed the tap was specific for it.


Top
   
 
PostPosted: Thu Oct 29, 2020 12:35 pm 
Offline
Moderator
User avatar

Joined: Wed Apr 15, 2009 5:25 pm
Posts: 11831
Location: Oswestry
I've got a wide range of taps and inserts in BSF, and the taps are specific to that particular brand of insert. My Metric ones are like that too. I think you'll have to buy the specific size for the brand of insert used?

_________________
If your dreams don't scare you, they are not big enough.


Top
   
 
PostPosted: Thu Oct 29, 2020 1:08 pm 
Offline
User avatar

Joined: Mon Nov 07, 2011 7:10 pm
Posts: 3103
Current ride: Buell ulysses
Location: Telford
Adam wrote:
I think you'll have to buy the specific size for the brand of insert used?

:yup: yes lots of choice out there , helicoil, wire insert,...... and all slightly different .

_________________
Buell Ulysses XB12X 06/08
CCM R30 (650cc) 02
Norton Dominators


Top
   
 
 [ 5 posts ] 

All times are UTC+01:00


Who is online

Users browsing this forum: CommonCrawl [Bot], ursus americanus and 0 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Limited