Broken bolts

[Wayne Crosby]

"a small carbide end mill!"
I think you mean a slot drill, end mills are for milling on an end or an "edge"

in my Timcert kit there are 3 slot drills for use with 6mm, 7mm and 8mm, I bet the next time I need one it will be 9mm, 10mm or 12mm, I shudder to think what the cost of that metal case containing all those drills, countersinkers, taps and and inserters would be npw, wrong side of £500/£600 probably
CLEM

I am talking about a center cutting end mill, you're talking about old school HSS garbage!
Things have moved on completely, plunge cutting 4 flute carbide end mills are the norm now.

 

[Wayne Crosby]

Hopefully you can see clearly the images, the one on the left is an old tech 6 flute HSS end mill, it has a center for sharpening between centers on a cutter grinder, these things are rarely used nowadays, they just cannot handle feeds and speeds modern cnc can provide, best left in the scrap bin or for home shop Myford type of users
Centre one is again an old tech HSS slot drill with 2 flutes, one of which is centre cutting, again, best left to home shoppers
One the right is a run of the mill Carbide end mill, 4 flutes, an opposite pair meet in the center so it can drill, plunge mill, helically interpolate, slot, adaptive clearing, mill along an edge etc, with these and with cnc control, you can do so much more than old school manual milling could ever do, example, on a standard Bridgeport turret mill, making fork yokes, it would take me 3 whole days on some if there is curves, radii etc and just forget about involutes.
The same set of fork yokes can be now done in a couple of hours (this includes design, model and program with good CAD CAM programs, with all those complex geometries carried out (even stanchion holes) with one tool, machining with cnc, over the last 25 years has been a complete game changer, and its the reason your new motorcycle, or car, can be made so much quicker

 

[GregT]

Thanks for all the replies Gents....my responses in no particular order...

In my case I've found that I do need to dismantle these. The diaphragms are original and one was cracked.

I've got a small impact driver, but using it occurred to me too late.

They aren't Loctited, they just have never been undone and the bike has been sitting for years.

Given the amount of heating and freezing and soaking I have been giving them, I think a trip to a machine shop is the safest bet.

GregT I am in the Wairarapa, you know anyone down this way you would recommend?

cheers,
Tony

Closest I'd recommend would be Pete Sales at Total Motorcycles just outside Palmerston North. Been around long enough that if he can't do it, he'll know who can.