What type of washer do I need?

[Shepherd999]

No matter how much I tighten the wheel , the seat backrest always slips down sooner or later. This might seem a silly question, but what is the best type of washer to stop this? Ideally it would not cause scratching etc. but it would not be the end of the world if it does.

 

[footprints]

Star washer, but that will scratch, you might find a rubber washer (bath tap) works otherwise if you keep it in one place Loctite on the thread (if it is unscrewing rather than just slipping down. Loctite can be undone but it takes some effort.

https://www.dunelm.com/product/loct...bVlDSORFYQJBeJiGr5RoCPd4QAvD_BwE&gclsrc=aw.ds

 

[Harry Bloomfield]

A soft washer, maybe a tap washer, might be enough to provide the grip you need. Other than that, a shack proof star washer, but it would scratch the surface.

 

[freddiemercurystwin]

What about a bonded epdm washer eg https://www.ebay.co.uk/itm/353733594551?chn=ps&_ul=GB&mkevt=1&mkcid=28&var=623092311075 You've not said what size thread it is?

 

[Shepherd999]

It looks like an M8. I would guess the advantage of this over a standard tap washer is that the screw won't rip into the the rubber?

 

[freddiemercurystwin]

Yes, they're designed for sealing rather than gripping but epdm is fairly grippy under compression.

 

[jj4091]

A penny washer then spring one on top of it https://www.google.com/search?q=pen...gARgKmAMAkgcHMTMuMTAuMaAHx4AC&sclient=gws-wiz

 

[JohnD]

Show us the other side. You could perhaps put a star washer under the nut and scratches would not show.

Or possibly EDPM tape stuck to the panel so an ordinary washer would grip.

There is an "Essex" washer sold for making taps grip.

 

[Shepherd999]

 

[JohnD]

Square rubber pad.

 

[Shepherd999]

There's not much space to fit the washer in between as it's limited by the size of the slot it slides in to.

 

[freddiemercurystwin]

What about some velcro sandwiched between?

 

[foxhole]

Patch of sand paper glued to back plate will give enough friction to prevent drop