Distributor gears

minorv8 · Post by **minorv8** » Mon Aug 03, 2015 4:45 am

I bought two SD1 type distributor drive gears to fit on a pair of dizzys but hit a problem. Both are heat treated so hard that drilling a hole for the pin is just about impossible. Normal drill bit hardly scratches the surface and the Co-alloyed bits won´t do either.

A file hardly leaves any mark. Factory original gears are much softer.

Does anyone have any ideas or tips ?

Blown v8 · Post by **Blown v8** » Mon Aug 03, 2015 5:26 am

My mate did mine,he's an engineer and ordered the specific bit,
Didn't take long with the right bit

minorv8 · Post by **minorv8** » Mon Aug 03, 2015 5:28 am

Yes, looks like tungsten carbide bit is needed. I contacted Rimmers to hear what they feel about the issue

unstable load · Post by **unstable load** » Mon Aug 03, 2015 7:18 am

You should manage it with a Cobalt bit. Keep the speed down and keep it well lubed to cool the tip.

minorv8 · Post by **minorv8** » Tue Aug 04, 2015 4:42 am

You should manage it with a Cobalt bit. Keep the speed down and keep it well lubed to cool the tip.

I should but the gear is so hard that even Cobalt bit won´t work.

Rimmer´s advice was to take it to an engineering shop. Excellent customer service

ged · Post by **ged** » Tue Aug 04, 2015 7:39 pm

A Stellite drill will go through like a hot knife through butter! Pricey though.