Webley End Block Retaining Pin

[bill57]

A question for the engineers amongst you.

I'm working on a rather tired Webley Viscount which is showing wear at some of the usual places. One area is the end block retaining holes, which are a bit slack and worn. The retaining grub screw through the block is missing, and the pin shows signs of having been driven out with the screw still fitted. The pin ends are mushroomed.

So to the point - I'm considering drilling the holes and end block oversize and making a new pin to tighten everything up. Standard pin diameter is 8.28mm, and I doubt if 8.5mm will be enough, so probably 11/32" (8.731mm) or 9mm. Question is, what material would you recommend to make the retaining pin from? Clearly it has to be machinable, unless I go with 9mm and hope that stock 9mm rod is a good fit?

All thoughts appreciated.

[mattyw1987]

How about a drill bit?

[Phil Russell]

I second the use of a drill shank if you can find one long enough. As to size, it depends on how big the enlarged holes are. I would be tempted to get an 8.5mm drill and see if the shank will fit or whether it is a push in but too loose fit. If it fits then you could use it. If not, then go a bit larger etc. When doing this, have a good look at the ends of the holes in case the end has peened over a smidgeon ... a finger nail is a good sensor. You may well end up with a bright shiny end on the new pin. Consider oil bluing it ... heat the end to just before red and quench in oil, old, dirty engine oil is best.
Cheers, Phil

[bill57]

Thanks for the input guys. You're on the same wavelength as me, I have use a drill bit in the past for similar applications - it's a sure way of knowing the pin fits, since it made the hole!

After some reading, I've ordered some silver steel rod, which is tough, heat treatable if needed, and ground to very exact sizes. 8.5mm isn't going to do, the holes are too worn, so I'm going 11/32" rather than 9mm - any meat saved has to be good?