Thrust washer

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Wolfie on 07/11/2016 13:47:50:
Ok I'm doing my first motorcycle restoration, it's basically a practice run and learning curve. I keep running across references to thrust washers and they look like normal 'round thing with a hole in' washers. I was trying to find out why they had this special name, what differentiated them from normal washers …

.

In that context … the differentiating feature is usually that they are hardened, and ground flat & parallel.

MichaelG.

[Martin ConnellyParticipant @martinconnelly55370]

The chances are no. They may need to be a material with good wear resistance or not liable to rust. Some materials self polish in use other gall up. Galling is what happens when two pieces of material rub together and become sticky enough relative to each other that they effectively cold weld. Some stainless steels are very prone to this. If you make a nice shiny thread on a stainless pipe and decide to test it with a nice shiny threaded female fitting they can stick together to the point where you have to cut off the fitting to get them apart (the answer is to use an anti seize lubricant on the thread first). Phosphor bronze is often used for plain bearing surfaces because it has good properties such as wear resistance, low corrosion and polishes up with use rather than galling up.

**LINK**

Martin

[HOWARDTParticipant @howardt]

As Martin says no. Thrust washer can be of almost any material, PTFE to ceramic. But the material is chosen for the application, dose it run dry or in an oil bath, is the load low or high and a multitude of other design criteria. If you are replacing an existing washer ensure it is the same material and hardness. When you understand the design rules you may be able to substitute materials. Also ensure that the mating faces are as they should be, any wear on the mating faces may lead to premature failure when you fit a replacement.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Wolfie, some thrust washers have rotating parts on them as has been said, but there are thrust washers that appear to be totally static or in a passive situation but in reality they may have a variable and or vibrating loads on them. If ordinary washers are used in these cases, they are liable to creep and the whole fixture will become loose, even if you are using lock nuts. As MichaelG has pointed out, these thrust washer are likely to be hardened to resist creeping when any variable or vibrating loads are applied to them.

Regards Nick.

[WolfieParticipant @wolfie]

OK thanks guys I understand thrust washers now.

I'm working from diagrams that aren't much more than parts lists so all I have is a picture with numbers on, and a list to check the numbers against thus part 86-1234 is a thrust washer.

So the next question is then if part number 86-1234 is missing, how the hell do I find out what it was made of??

Edited By Wolfie on 11/11/2016 16:56:03

[WolfieParticipant @wolfie]

Posted by Muzzer on 06/11/2016 13:43:25:

Wow. A moderator on a model engineering forum with 500 posts to his name lacks both the basic knowledge of what a thrust washer is – and the ability to Google it. I thought I had a good armchair!

 

 

Muzzer I'm a truck driver not an engineer, when you can reverse a fully loaded artic into the mill bays at Avonmouth mill and not fall into the dock without asking a truck driver how to do it then come and talk to me

The reason I'm a moderator has nothing to do with engineering and a lot more to do with the fact that I'm good at computers

Edited By Wolfie on 11/11/2016 17:01:10

[Neil WyattModerator @neilwyatt]

Posted by Wolfie on 11/11/2016 16:55:06:

OK thanks guys I understand thrust washers now.

I'm working from diagrams that aren't much more than parts lists so all I have is a picture with numbers on, and a list to check the numbers against thus part 86-1234 is a thrust washer.

So the next question is then if part number 86-1234 is missing, how the hell do I find out what it was made of??

Edited By Wolfie on 11/11/2016 16:56:03

Hi Wolfie,

What's the bike and what's the washer actually doing (besides thrusting)

Neil

[Chris GunnParticipant @chrisgunn36534]

Wolfie, if you were to tell us what bike you were working on or sizes then I am sure someone will know what 86-1234 is. It is more than likely it is or was a commercially made bearing which could be available.

Chris Gunn

[Mike PooleParticipant @mikepoole82104]

As it is now a long time since BSA made motorcycles or parts for them we are into pattern parts for supply, these range from as good or better than original to simply not fit for purpose. Thrust washers on motorcycles can be used for various purposes, some will take a continuous thrust load but others will have more of a shim role where they control any tendency for end float but don't have a continuous load. Often in a gearbox the washer will be bronze and be pegged to stop it rotating against the shell of the gearbox which would wear too quickly. If you have the original part and it is worn or damaged then a fair guess can be made about the original dimensions and material. There will often be some part of the original that is not worn so a dimension can be measured. If it is a steel washer then it will need to be made from a hardenable steel and ground or lapped to size after hardening. A bronze washer will often have a small hole to fit a peg in the casing to prevent the washer rotating and wearing the casing. A bronze washer will often have additional grooves to allow lubrication to reach the thrust areas. If you come up against a particular item that is missing or requires replacing then a picture of the part or the parts list number could help the bike friendly members come up with a useful suggestion. Membership of the relevant owners club can be very useful, they usually have a technical committee member who will know the answer or the right person to ask.

Mike

Edited By Michael Poole on 11/11/2016 18:06:51

[WolfieParticipant @wolfie]

Its a BSA C15

The 83-1234 isn't a proper part number, I was just using it for an example.

[John RuddParticipant @johnrudd16576]

Posted by Wolfie on 14/11/2016 11:41:16:

Its a BSA C15

The 83-1234 isn't a proper part number, I was just using it for an example.

Wolfie, how about some pictures please? Err I mean of the bike not the thrust washer…..

Edited By John Rudd on 14/11/2016 11:48:28

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