We have a lot of bits done at work by Wallwork in Bolton. We use the Tufftride AB1 process, which come out a lovely black colour – rather like the firehole door and other bits on my Edward Thomas… It is possible to have silver-soldered assemblies done, but the process is rather close to the melting point of Easyflo 2; however I've had no problems other than having to paint the silver solder black to match the rest of it!

It adds little or no size to the part. You need to have bits you want as running surfaces smooth before processing, otherwise smoothing it off later is a) difficult and b) wears away the very thin surface hardening.

Much of our stuff is just plain mild steel – 220M07 (En1A) or 070M20 (En3B).

A very useful aspect of the process is its excellent corrosion resistance – better than zinc plating.

It's not terrible expensive, but it's usually done by weight with a minimum order charge, so if you're doing watch bits they'll work out expensive.

(edittid foar spelin)

Edited By Nigel Bennett on 14/05/2014 13:10:20

Not sure it would be applicable in our applications particularly steam may be high speed IC engines.

It is normally used on crankshafts that are subject to higher loads than would normally be seen e.g. high performance engines. It used to be more applicable but with modern engine design less so. In some cases where the RPM of the engine is increased significantly a change of material to a chrome-moly steel or EN40B is normally the route taken as it is better for nitro carburizing (Tuftriding is a trade mark for the process). The crank is either forged or machined from a solid billet both processes are expensive and you'll pay in excess of £1200.00 for a 4 cylinder crankshaft.

It is RPM that is the killer as the loads on the crank, rods and pistons become more significant the fast they travel.

The camshaft on the Norton Commando (750 twin m/cycle, 1970s) was tuftrided to reduce wear, and it worked very well. I also understand that as the process introduces a compresive layer in the surface, it improves fatigue resistance (for the same reason that shot-peening does but without roughening the surface). This is a further benefit for crankshafts.

Cheers, Tim