5mm X 8mm prop spacers

[Bartman]

I bought eight of these recently and paid $2.34 each!!! I need to restock and found them at McmasterCarr.com for about a buck each

http://www.mcmaster.com/#spacers-and-standoffs/=b39nmc

If anyone buys them from here please let us know how they work out. I may order a bunch tonight and I'll pass along how they fit when I get them. They're also available in 8mm length.

Bart

 

[Bartman]

and here's a real prop washer.

thought i had it but i was wrong. i'll replace the link when i find the right part (a 5mm ID aluminum prop washer)

it might be a tight fit but it can be drilled. my prop hubs came with a star type lock washer which wouldn't be my first choice for a prop washer.
regards,
Bart

 

[Bartman]

this is being discussed in another thread so I thought I'd update this post with more info.

a 5mm inside diameter prop insert won't fit snugly on a 5mm threaded shaft. the process of cutting threads onto the shaft removes enough material where it isn't 5mm in diameter anymore. after being threaded it's more like 4.9mm which doesn't sound like a big change but it's enough slop for a 5mm spacer to be unuseable. the way i've found to get around this is to use a 4mm ID spacer and thread it with a 5mm tap. once the threads are cut i just run a drill bit through it to get the .49mm ID correct and it goes right on. the reason i tap it before drilling is to remove some material without losing the concentric quality of the inside hole. the .49mm (or equivalent) drill bit is then just cleaning out the threads and stays centered in the hole.
Hope that helps. don't forget (like i did) to buy yourself the prop washers above as they span over the 8x5mm prop inserts and crush down on the actual prop material a little. they're a necessity on the wood props also.
Bart

 

[RTRyder]

this is being discussed in another thread so I thought I'd update this post with more info.

a 5mm inside diameter prop insert won't fit snugly on a 5mm threaded shaft. the process of cutting threads onto the shaft removed enough material where it isn't 5mm in diameter anymore. after being threaded it's more like 4.9mm which doesn't sound like a big change but it's enough slop for a 5mm spacer to be unuseable. the way i've found to get around this is to use a 4mm ID spacer and thread it with a 5mm tap. once the threads are cut i just run a drill bit through it to get the .49mm ID correct and it goes right on. the reason i tap it before drilling is to remove some material without losing the concentric quality of the inside hole. the .49mm (or equivalent) drill bit is then just cleaning out the threads and stays centered in the hole.
Hope that helps. don't forget (like i did) to buy yourself the prop washers above as they span over the 8x5mm prop inserts and crush down on the actual prop material a little. they're a necessity on the wood props also.
Bart

One of the reasons I prefer the Grauper plastic adaptors, I've found them to generally be about 4.85mm ID and a VERY snug fit on a 5mm prop adaptor, I've actually had to open them up with a 5mm drill bit in some instances where the shaft of the adaptor isn't threaded all the way to the bottom.

Ken

 

[Bartman]

but they cost $$$!!!

 

[Bartman]

the part number above for the prop washer is incorrect. i ordered a bunch and the hole in the washer is 6mm which it too big for a 5mm shaft.

i'm trying to find a suitable part and will post it here when i find it.

bart

 

[Droider]

If you look at the Graupner ones real carful you will see that they are actually tapered. Well all the ones I have received anyway.. and thats a fair number since I have 8 11 and 1 10" props. I dont cut them down either. I have been fitting the larger side down and push them in so that they are flush with the bottom of the prop. This leaves the excess protruding about 1/32nd" when you tighten the retainer nut down on the washer the washer compresses and tightens on to the thread. I know this because even if you take the nut off when it has been fitted the 1/32nd" has gone and you have to unscrew the prop off.

Thats how I have fitted all mine

 

[Bartman]

Dave,
That's a very interesting take on those spacers. I'll have to give them a closer look but it sounds like you may have cracked the code on why they're slightly longer than the props they fit into are thick.
Well done!
Bart

 

[Droider]

Just checked my spares.. they are definitely tapered. 5mm rod will go in snug at one end but wont go in the other.

 

[Buzzed]

and here's a real prop washer.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXUA40&P=7

it might be a tight fit but it can be drilled. my prop hubs came with a star type lock washer which wouldn't be my first choice for a prop washer.
regards,
Bart

This appears to be a 5mm prop washer does anyone know a source for 8mm prop washers?

 

[Bartman]

i thought they weren't very precisely made but maybe you've managed to match wits with the Germans. {add sounds of wonderous ooohing and aaaahing}

 

[Bartman]

This appears to be a 5mm prop washer does anyone know a source for 8mm prop washers?

Buzzed,
I've got to remove that link. Those washers are 6mm ID (or some SAE equivalent) and they don't fit the 5mm MK prop/motor adapter shafts.