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Transfer box breather

Posted: Fri Apr 12, 2013 5:22 pm
by dunnin21
Iv got hold of a new transfer box. Before I put it on I'm gona do the breather. So who can tell me what size elbow and tap I need to use. Just the hole is 12mm already

Thanks andy

Re: Transfer box breather

Posted: Fri Apr 12, 2013 9:13 pm
by dunnin21
Any idears

Re: Transfer box breather

Posted: Fri Apr 12, 2013 9:22 pm
by Tramp
1/4 bsp, did you pull the collar out if the casing? It's an interference fit,

Edit*
Definatley 1/4 bspf as its the only bsp tap set I have.....

Re: Transfer box breather

Posted: Fri Apr 12, 2013 9:32 pm
by Darrell
:thumbup:
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Re: Transfer box breather

Posted: Sat Apr 13, 2013 10:14 am
by dunnin21
Yeh I took nipple out the hole just seams large for a 3/8

Re: Transfer box breather

Posted: Sat Apr 13, 2013 4:48 pm
by Ladaman
BSP threads are based on the bore of the pipe, not the outside diameter of the bolt as normal threads are.

If you notice on the table Darrel attached the outside diameter of a 3/8"BSP thread is 0.656" or 16.6mm

Having said all that though, I've just checked mine, and I'm sure it's a 1/4"BSP thread I used which is 0.518" or 13.15mm outside diameter. The hole already in the case is close enough to the correct tapping drill size to not need to drill it out.

I recall I put some grease on the tap to hold the swarf, and had the gearbox as close to upside down as I could get it to stop the swarf entering the casing.

So believe it is 1/4" BSP you really need.

Re: Transfer box breather

Posted: Sat Apr 13, 2013 5:04 pm
by Darrell
Ladaman wrote:BSP threads are based on the bore of the pipe, not the outside diameter of the bolt as normal threads are.

If you notice on the table Darrel attached the outside diameter of a 3/8"BSP thread is 0.656" or 16.6mm

Having said all that though, I've just checked mine, and I'm sure it's a 1/4"BSP thread I used which is 0.518" or 13.15mm outside diameter. The hole already in the case is close enough to the correct tapping drill size to not need to drill it out.

I recall I put some grease on the tap to hold the swarf, and had the gearbox as close to upside down as I could get it to stop the swarf entering the casing.

So believe it is 1/4" BSP you really need.
I've no idea of the hole size , but that makes sense :thumbup:

Re: Transfer box breather

Posted: Sat Apr 13, 2013 9:11 pm
by dunnin21
Thanks guys I shall go for the 1/4