Product review: Clarke M8 thread repair kit
By Sean Warwick -
Parts & accessories
02 February 2012 15:14
Clarke M8 thread repair kit, £17.99
What’s good: If you spend any amount of your time fiddling with older bikes in the garage, it’s only a matter of time before you’ll encounter a stripped thread, typically where a steel fastener in an aluminium engine case has been overtightened or become corroded.
Whether the cause is your own ham-fistedness or the result of a previous owner deciding that, contrary to the opinion of the bike’s designer, an effective fastener wasn’t actually required in that particular location, it is only marginally less infuriating than snapping a bolt off in a casing.
But thread repair isn’t a costly job that needs referring to a specialist – it can be done for less than £20 in a few minutes with the assistance of a suitable sized repair kit. I bought a Clarke kit to cut a new M8 x 1.25 thread for a loose steel stud in the cylinder head of my BMW R80.
It contained an oversize drill to clean up the hole in which the thread had failed, a tap which is used to cut a thread for the replacement “thread insert”, and a load of the diamond-section stainless inserts themselves, which, when screwed in place, become unscrewable and magically restore the original thread size.
There was also a special tool to guide the insert in place, and even a punch used to snap off the lug on the insert on which the special tool locates.
I found that as long as you take care to keep your drillwork square, centred and to the correct depth, and don’t forget to fish the broken-off lug out of the hole, it’s almost foolproof.
The Clarke kits are also nearly half the price of the best known thread repair brand, Helicoil.
What’s not: Bafflingly, there were no paper instructions included with my kit. Also, if you don’t already own an adjustable tap wrench of the type found in tap and die kits, you will have to buy one – otherwise you will struggle to use the supplied tap correctly.
Contact: www.machinemart.co.uk
Rating: 4/5
