12 replies to this topic

[Gaz66]

Ive just stripped a gearbox for my project and noticed the sump plug has stripped at some point and been helicoiled.
The helicoil is hanging inside the gearbox by around 15mm so its either wound itself in as the plug was screwed in or never was cut to length in the first place.
Anyway. ....cut to the chase.
Im going to go down the 20mm tapped bolt route with the standard sump plug screwed into that etc etc.
Would a coarse thread bolt be better than a fine thread for loctiting in?

Edited by Gaz66, 13 May 2023 - 08:33 PM.

[Quinlan minor]

A Time-Sert would be my recommendation.

[Gaz66]

A Time-Sert would be my recommendation.

Thats ok if you have the tooling to do it otherwise its a bit expensive.
If I could find someone who had the tooling it may be an option.

[Tds76]

A fine thread is more suitable than coarse - stronger and more contact surface for the same nominal size.

[Gaz66]

A quick look on the net shows helicoiling only at the machine shops near me (Leeds) so the time sert option is looking grim at the moment.

[Steam]

Helicoil works well for this fix. Did one 3 years ago and still fine after numerous oil changes.

[GraemeC]

At that size I feel a standard M20 will be course enough

[Spider]

I've done many now, I just use a standard M20 x 2.5 for this.

[Shooter63]

Tadaaa

Shooter

Attached Files

•  Spider special.jpg   125.65K   3 downloads

[Gaz66]

Tadaaa

Shooter

That looks cheeky 👍
What size sump plug did you use?

Edited by Gaz66, 14 May 2023 - 02:33 PM.

[Shooter63]

Tadaaa

Shooter

That looks cheeky
What size sump plug did you use?

First off it's not my idea, I nicked it off spider, all I changed was the sump plug size to 14mm and to be honest I used that size because I already had a tap in my tap and die draw. Total cost was about £3.00 for the material £4.00 for the sump plug and £18,0000.00 for the electricity to power my lathe for 1/2hr

Shooter

[Gaz66]

Sump plug update.
I just took out the sump plug and the helicoil is fully fitted and not wound out into the inside of the gearbox.
Now then, do I just chop it off inside the box and leave it or take it out and do the adapter. Decisions decisions.
Are helicoils difficult to remove?

[Steam]

If it works and doesn't leak I would leave it. If it aint broke don't fix it.
The only way to get helicoils out is to wreck them winding and pulling like a spring.