Scrap items - by Ron Hayhurst - Download this article here

 

DON’T THROW AWAY THAT SCRAP ITEM!

In other words, consider first if the scrap item can be put to a different use. For example the inner and outer races of old bearings can easily be ground down, on the diameter that normally make an interference fit, using a bench grinder or abrasive flapper, to turn them into spacers for tapping or pressing new bearings into their housing. Now that they are a sloppy fit in any housing, that can also act as depth gauges e.g. if you are not sure of the depth of your crankshaft front mains housing.

If you need to straighten out a wavy flange on an oil baffle, the ideal “forming” tool is the outer race of one of the angular contact front main bearings. It just needs a notch grinding in it to accommodate the locating joggle.

An obvious use for a dynamo support bracket, scrapped due to a split in the housing that carries the fan spindle, is to keep the grot out of an engine laid up as a spare, or awaiting attention. It simply needs a cover, made from thin sheet metal or wood, to go over the hole where the dynamo fits. Similarly there may be a gap over the gears where the nose cone has been robbed for the “other” engine - there’s a bit of a shortage of good, correct length nose cones and something of a surplus of ones that are about to be scrapped. When they are fitted to the spare engine, don’t they just get in the way! Sticking out from under the bench, trying to trip you up! The answer is to saw down through the scrap nose cone, in a line 1¾" from the face which mates with the crankcase. You will find you have a neat 1" hole plus a small drain hole in the new flat face. Blanking these holes now turns the scrap nose cone into a useful cover for the front end.

A chewed up round pin on the inboard end of the starting handle may cause problems when cranking the engine, or prevent the handle from locking in the horizontal. A replacement is fairly easy to make from an old big end bolt. It is made of just the right material for this heavy duty.

Having found a contact to do the odd machining job, you may be asked to bring along some bar stock! Alternatively you may have a concern over the strength of material your contact will use! This is perhaps the time to look for that old half-shaft with the chewed up keyway or the pinion with the chewed up gear - they are both made from very tough steel.

Old valves can be cut back to make drifts, riveting tools or podgers.

There must be numerous other dodges similar to the above fairly obvious examples. It would be good to learn about them in (say) letters to the editor!

ON THE OTHER HAND

Finally and contrarily, a plea for some things which should be scrapped, viz:- necked bolts Whitworth ¼" bolts are the main culprits. When a bolt is over-tightened it will stretch and show a reduced diameter which can be seen when examined against a strong light and straight edge. This means it has been loaded beyond its yield point and is well on the way to failure in service. Also it will be found that when running a nut along the bolt thread it will suddenly become stiff to turn at the point of necking (even when apparently OK against the straight edge). Necked sump bolts are often the reason behind a seriously damaged thread in the crankcase where the stretching has changed the thread pitch. In pulling such a bolt into the softer aluminium, the female thread takes on this deformed profile and can easily be stripped. Big end bolts are the other bolts where a very careful check is needed. If in any doubt scrap and fit new.

 

Download this article here