Author Topic: How does this clutch work?  (Read 3758 times)

Offline Brian Rupnow

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Re: How does this clutch work?
« Reply #30 on: September 24, 2018, 12:01:43 AM »
I don't post very many set up shots anymore, but this is a worthy one. No, it's not a Maltese cross, it's the hub that will hold the four comma shaped arms. There is more work yet to be done on it.

Offline crueby

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Re: How does this clutch work?
« Reply #31 on: September 24, 2018, 02:34:57 AM »
 :popcorn: :popcorn: :popcorn:

Offline Brian Rupnow

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Re: How does this clutch work?
« Reply #32 on: September 24, 2018, 05:12:51 PM »
Now, is that a beautiful thing or is that a beautiful thing? I chickened out at the very last moment and put the slots in with a 1/8" carbide endmill instead of using my slitting saw. This part is steel and I didn't want to take a years life off my slitting saw. I took 0.010" deep cuts with the mill running at 1300 rpm and hand cranked very cautiously so as not to snap the endmill off.

Online Ye-Ole Steam Dude

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Re: How does this clutch work?
« Reply #33 on: September 24, 2018, 05:17:17 PM »
That is beautiful work Brian.

Have a great day,
Thomas

Offline Brian Rupnow

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Re: How does this clutch work?
« Reply #34 on: September 24, 2018, 05:19:08 PM »
Now it's my turn to ask a question. What can I buy for a friction disc. The disc stands alone and is not attached to anything, simply centered on the shaft. In a perfect world, I would like something about 1/16" to 1/8" thick. Whatever it is, it has to not only have very good friction surfaces on it, but must be durable and capable of holding it's shape. It needs to be 2 1/4" diameter. If I don't get a good answer to this question, I may default to a piece of 1/4" plywood for a friction disc.

Online Vixen

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Re: How does this clutch work?
« Reply #35 on: September 24, 2018, 05:39:46 PM »
Hi Brian,

A plywood friction disc would be a good choice, especially if you can win some aircraft grade spruce ply. My old 1932 MG had multiple ply inserts in a steel disc for it's clutch plates, they were soaked in an oil bath, but did not slip.

Alternatively, you could try glass fiber printed circuit board, it's often pale green in colour, don't recommend the brown laminated paper/ resin stuff. Look out for some PCB with double sided copper. Either chemically etch or perhaps rip away the copper laminate. The exposed surface is rough with high friction. In the past, I have used it for the steering transmission for a 1/6 scale model tank

Mike
It is the journey that matters, not the destination

Online gbritnell

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Re: How does this clutch work?
« Reply #36 on: September 24, 2018, 06:20:38 PM »
Use a piece of leather. Available at most craft shops or on good old EBay. I save my old wallets for a good thin leather source.
gbritnell
Talent unshared is talent wasted.

Offline michaelr

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Re: How does this clutch work?
« Reply #37 on: September 24, 2018, 07:14:34 PM »
Cork was one material that was used for clutch friction plates, may be still obtainable today.
Michaelr

Offline Brian Rupnow

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Re: How does this clutch work?
« Reply #38 on: September 24, 2018, 08:19:25 PM »
I went down street on a shopping trip today, and bought a 3 foot length of 1" x 1/8" precision ground 01 steel to make the comma shaped pieces from. Also bought a couple of very healthy small springs, one of them will work on the end of the clutch shaft, not sure which yet. Also picked up a sprocket which can be bored out to fit the appropriate clutch hub. I sawed off four 1 1/2" long pieces of the 1 x 1/8" 01 material, lined up the sides and one end, and clamped them in a set of welding vice grips. I will put a dab of mig weld on the ends which will be trimmed away after the fact, so I can machine all four pieces at the same time to ensure that they are all the same.

Offline Tennessee Whiskey

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Re: How does this clutch work?
« Reply #39 on: September 24, 2018, 08:37:47 PM »
+1 on the leather

Whiskey

Offline Brian Rupnow

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Re: How does this clutch work?
« Reply #40 on: September 25, 2018, 01:09:09 AM »
I'm curious--those of you who have suggested leather, how would you use it. Would you glue it to the face of one of the discs, or just let it free float between the two metal discs?

Online gbritnell

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Re: How does this clutch work?
« Reply #41 on: September 25, 2018, 03:19:07 AM »
You could do it either way but I would let it float. The diameter is small enough that it won't (shouldn't) flop around.
gbritnell
Talent unshared is talent wasted.

Offline Ian S C

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Re: How does this clutch work?
« Reply #42 on: September 25, 2018, 03:34:35 AM »
I'v seen suggested that slices of wine bottle corks glued to the clutch disc work ok.Don't have to be cut evenly at first, just stick them on, then dress to a flat after the glue has set/cured. Another source of cork is the old fashoned cork place mats for the dinning room table.
Ian S C

Offline Bluechip

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Re: How does this clutch work?
« Reply #43 on: September 25, 2018, 08:20:08 AM »
Cork floor tiles are readily available ( in UK anyway   :thinking: ) Good for lining tool-box drawers  :ThumbsUp:

The greeny-grey fiberglass PCB laminate is usually FR4 grade. ( fibre ?? )

Some clutches I encountered on old computer stuff were made from SRBF.

I would go for for leather.

Dave

Offline Brian Rupnow

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Re: How does this clutch work?
« Reply #44 on: September 25, 2018, 02:31:05 PM »
Cuttings from the west coast of Canada has kindly volunteered to send me a piece of friction material from McMaster Carr. So far I have two or three recommendations for leather, one for plywood like I originally suggested, and one for an abrasive disc. The whole idea of a friction clutch like this is that it engages gradually, and not with a sudden grab like a jaw clutch. I think that lets out the abrasive disc suggestion. I do have a cone clutch which I designed a few years ago, on which the cone material is oak wood. It works very well, but then again my engines are only very fractional horsepower engines.