Layrub Coupling

[Shox Dr]

Question is, will it come out?

 

[Shox Dr]

And the answer is. YES


Looks like I took it out too fast as it ripped



Not bad for a first attempt

 

[Shox Dr]

On closer inspection of one of the centres, there’s a difference in surface finish after blasting. Looks like the shiny area is where the mapp torch was directed. Its harder than the dull area, while still hard a file does put a shine to it, where as the shiny area the file just skids over.
What gives? Not hot enough?
Think I’ll anneal, blast and reharden. Hopefully the glass blasting will give a good key for the resin

 

[Shox Dr]

Didnt bother fully annealing them, put them in the wood stove and left them over night.
Its done a good job of tempering them. Blasted with hopefully a good key for the epoxy to grab

 

[Shox Dr]

MkII. Notability less bubbles.
I’ll leave this one in a bit longer. The mould has been polished with bees wax, hopefully it will release. If it causes problems, I might make one out of Delrin

 

[eSCHEn]

Any access to a vacuum pump Shox? That's the usual way you see pourable stuff being degassed. Get the whole thing into a paper cup or whatever you're mixing in and then but that into a vacuum pot and drop it as low as you can get. It'll "boil" because of the reduced air pressure so leave plenty room.

 

[Shox Dr]

Any access to a vacuum pump Shox? That's the usual way you see pourable stuff being degassed. Get the whole thing into a paper cup or whatever you're mixing in and then but that into a vacuum pot and drop it as low as you can get. It'll "boil" because of the reduced air pressure so leave plenty room.

No, something I’ve not required. Wanted a vac pump but not the pot. Had a look on ebay not sure what size pump I require. It starts to thicken up after 3-4mins so don’t want it to take along time degassing

 

[Shox Dr]

Happy with MkII. Split very easily

 

[Shox Dr]

No2


Nos 3 on the brew

 

[Dcal]

Hopefully the glass blasting will give a good key for the resin

I've never had good results getting pu to stick to blasted steel.
I used silicone molds so it is possible the steel surfaces got contaminated.
I was told shellac is a good primer for PU to steel but haven't got around to trialing it yet.

Hope yours works as intended.

 

[Shox Dr]

I gave them a call before ordering to ask about surface prep. Was told a primmer wasn’t required.

 

[Shox Dr]

Soooo, I’ve been putting this off of a few days, as I wasn’t confident on a happy ending. Ended up turning them down taking 0.4mm off. I used Vaseline to help them in. Combinations of washers sockets and machine screws got a pair in each side. Then longer sets to pull the halves together. It went without comment





Many thanks to @Pete. For suggesting epoxy. Hopefully they will hold out. Just in case I’m going to make another set

And the yokes fits

 

[Pete.]

Nothing like a bit of DIY for maximum satisfaction

 

[Shox Dr]

Nothing like a bit of DIY for maximum satisfaction

Totally, its why we are all here.

 

[Shox Dr]

Out of curiosity, I chucked the lot up in the 4jaw to see what the runout was like on the prop.
There’s about 20thou. I have no idea if that is within tolerance. Didn't fancy running it up to full speed, the jaws only have about 4mm grip on the gearbox yoke.

 

[Pete.]

I'd be overjoyed with 20 thou.

 

[Shox Dr]

I'd be overjoyed with 20 thou.

It looks like the shaft has been welded to the yoke, ground back and chromed. The yoke doesn’t nod, indicating 50mm along the shaft, its less but hard to see because of the flaking chrome. So could well be less than 0.015"
I guess you could indicate along the output splines. OTT other than curiosity

Considering it needs to flex for suspension. I’ll call that a success.

(Looking to buy a vacuum pump and chamber for future moulds, and machine from acetal, or similar)

 

[reb78]

Whenever I peruse the Brew Room, this thread catches my eye. I think it’s because, at a glance, I read the thread title as Ladyrub Coupling.... and that sounds interesting...

 

[Shox Dr]

I'd be overjoyed with 20 thou.

The BSF bolt I lost turned up today. It was for the gearbox side yoke. Snugged up it’s brought it down to 10thou

 

[Shox Dr]

Well they didn't last long. The output side has walked out of the casting.


Might be lack of adhesion, Looks like they have walked out the bush. Wonder if the resin is too hard and isn’t flexing.

The sleeves are scrap, but worth modifying. So I brazed a washer midway, and have cast another set


That will stop them been pulled out, whether the resin has enough flex is to be kept an eye on.