I am just about to re-assemble a 74, Alpina 137, 250 engine. Whilst apart I am going to replace the gearbox bearings. The retainers for the bearings have countersunk screws with tapered serrated washers, several of these screws have collapsed whilst unscrewing.

 

Countersunk serrated washers seem difficult to locate and wondered whether you chaps use these washers, compress regular serrated washers or just use thread sealant?

 

Your thoughts would be appreciated.

I have used normal serrated washers and just tightened them up and they seem to be fine. I have had them apart again and all is okay. Graham.

Countersunk serrated washer are very OK, they are called DIN 6798 Fächerscheiben Form V = versenkt as we name them, they should be easy to get, here one address were you can order just 100 at once ... https://www.wegertseder.com/index_prod.asp

 

They work best. Nowadays you can use countersunk screws with Allen (female) head which are easier to thighten and loosen again,

again the link where top find: https://www.wegertseder.com/index_prod.asp (if you have difficulties to find them).

I usually use no washers but do use loctite. The reason I don't use the washers is that I fear that a piece might come loose and cause damage

Thanks for the input. Good point about hex head countersinks. Those slotted screws are the work of the devil.

I got stainless steel serrated washers and hex head countersunk screws from the well known auction site. no problem. The hex head screws are so much better to use.

Hi all iv'e also found it hard to find those counter sunk shredded washers and hex head srews seem a better option those srews can be a pain.

Edited August 25, 201511 yr by bondy

Try Avon Stainless Fasteners Bondy. You should find them on their site

Nice 1 noel063 i will take a look