Re-threading a hole on a OS55HZ Crank case

[discoferret]

Just got back from flying the velo and noticed that I had a leak from the back plate of the OS55. I knew one of the bolt holes had threaded but was hoping that the other 3 would be enough to tighten the back plate up but its not. Whats the best way of getting it re-threaded? I was going to re-tap it, but use a M4 8mm socket bolt instead but I dont think there is enough metal to drill into. What do you guys suggest I do? I dont want to buy a new case which is £60!

[sacko]

Helicoil it.

[electricsceadu]

get a 3mm helicoil fitted to it

[mark Taylor]

Just tap up in the next imperial size
Go to a local engineers supply and get a tap and imperial caphead bolt

You don't have a great deal of metal to start opening it up more

I'm sure you'll find you should be able to just tap your existing hole with a new thread

[electricsceadu]

Just tap up in the next imperial size
Go to a local engineers supply and get a tap and imperial caphead bolt

You don't have a great deal of metal to start opening it up more

I'm sure you'll find you should be able to just tap your existing with a new thread

with a m3 helicoil you drill the hole out to 3.2mm
there should be enough room to do it

[discoferret]

Cheers guys I will give all you suggestions ago.

[nookybear]

could go m3.5

[pgkevet]

before you do anything just try a longer m3..you might get lucky

[discoferret]

before you do anything just try a longer m3..you might get lucky

Ive already tried it.

[debrooker]

i'd be very careful as the alloy is really soft.

[Edders]

I have a spare crank case or two of you want to pay postage

Edders

[discoferret]

I have a spare crank case or two of you want to pay postage

Edders

That would be great mate. Really appreciate it. How much do you want for postage? I will send via paypal. PM me your paypal account name.