# Line-Shaft Clutch



## Brian Rupnow (Oct 3, 2016)

After doing a bit of research on line shaft style clutches, with a manually operated swing lever to actuate them, I've decided to build one, "Just to see if I can!!" (This train of thought was brought about by John who is building the 19th century machine shop diorama on Model Engine Maker). A bit of research yesterday showed me that the smallest I can possibly make this clutch is 1.75" outer diameter, to work on a 1/4" diameter shaft. There are a few parts to this "expanding shoe" style of clutch that become too small for me to make if I try to make the clutch smaller in diameter. I have made use of a keyslot cutter in a very unorthodox manner to get started on this, and since I'm doing this in "real time" I will keep you posted of my progress.---Brian


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## Brian Rupnow (Oct 3, 2016)

This is the center hub of the clutch. It is fixed to the line-shaft. The expanding shoes which transmit torque to the outer hub slide in the miniature T slot which was cut thru with the keyway cutter.


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## kadora (Oct 3, 2016)

Hello Brian 
Nice work .
Could you please describe briefly how T slots are cut?
It is mystery for me.
Thank you.


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## Brian Rupnow (Oct 3, 2016)

kadora said:


> Hello Brian
> Nice work .
> Could you please describe briefly how T slots are cut?
> It is mystery for me.
> Thank you.


Look at the top picture. It shows exactly what I done. First I cut a slot .125" wide full depth across the top of the brass part in the chuck with an endmill.  Then I chucked up the keyway cutter and ran it all the way thru the brass part. Done!! I am sure that this is probably not the correct way to do it, but it is what I done.--Brian


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## Brian Rupnow (Oct 3, 2016)

Some very close (fiddly) work here. First picture shows cutting a 1/16" slot into one side of the sliding pressure shoe. Second picture shows the sliding pressure shoe  profiled for a sliding fit into the brass part. That slitting saw blade is 1/16" wide!! Next step will be to separate the sliding shoe into two pieces, one to bit on each side of the center of the brass.


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## Herbiev (Oct 3, 2016)

Interesting project Brian. I shall be following with great interest. Looks too fiddly for me to attempt tho


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## Brian Rupnow (Oct 3, 2016)

Herbie---It IS fiddly. it is just about at my limit for "small stuff". The "sliding pressure shoes" are finished. the side where you can see the heads of the socket head capscrews faces inward towards the clutch drum. The side where you see the slots and the shanks of the #40 shcs faces out. The dark blue "actuator arms" (as per the solid model) fit thru the slots in the brass part and bolt to the "sliding pressure shoes". There is a full 8 hours in what you see here.


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## Brian Rupnow (Oct 3, 2016)

This is a "real" line-shaft clutch set-up, and it is what serves as the basis for my design. One thing that the "real" one has and my model doesn't (because of scale/space restrictions) is individual adjustments for the tapered surfaces on the arms that the sliding cone interacts with. That would serve to adjust the sliding pressure pads on each side to contact the inside of the drum equally. At the scale I am working, there simply isn't room for threaded adjusters, so  I will have to resort to grinding the angled contact surfaces on the dark blue "arms" to get equal travel/pressure on both pressure pads.


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## Brian Rupnow (Oct 3, 2016)

I don't THINK that there were any springs in there to retract the shoes and disengage the clutch, but I really don't know. That picture is one I downloaded off the internet. I have never seen one of these clutches in "real life". If anyone has info to the contrary, please let me know.---Brian


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## Brian Rupnow (Oct 3, 2016)

I'm going to make a small change to the pulley drum. Since most of the machinery I drive use 1/8" diameter rubber O-rings as drive belts, and we will want to actually "field test" this clutch, I have put a groove in the green drum to keep the o-ring in place on the pulley.


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## Brian Rupnow (Oct 4, 2016)

This morning I decided to make "easy" parts, that just required turning. I checked all of my bins, and found that I didn't have any round steel large enough in diameter to make the outer 'drum'.---I did however have a piece of 2" diameter cast grey iron left over from the cylinder on the Rupnow Vertical engine. I decided to use it. This has a good side to it, in that it won't need a bushing where it rides on the revolving line-shaft when the line-shaft is turning and the pulley is not turning. The bad side is that cast iron isn't the strongest metal going, so I left the rim a bit thicker than my original intent. the finished diameter is now 1.725". I did find a piece of cold rolled steel to make the set collar from. That set collar keeps the drum from "drifting away" from the correct position.


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## Charles Lamont (Oct 4, 2016)

Brian, I think you may have a problem with getting much force where the shoes press on the pulley. The actuating arms look to be about three times as long
as the shoe guides. After the shoe makes contact with the pulley, any further pressure on the actuating arms will create a torque that tends to jam the shoe in its guide slot, losing a lot of the actuating force to friction. You could improve things by making the arm as short as possible. 

However, It seems to me more likely that in the original device the arms are in fact levers, pivoted on the hub 'behind' the shoes. This would hugely improve the mechanical advantage obtained, and greatly reduce the chance of problems with friction within the mechanism.

HTH.


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## Brian Rupnow (Oct 4, 2016)

Well, it sorta/kinda works. The angle on the contact surfaces which I arbitrarily picked as being 45 degrees is too steep. I have a 45 degree angle on the nose of that 3/4" diameter slider and with the lathe running at about 60 rpm I can hold the pulley drum from rotating with a finger. If I use my other hand to force that 3/4" diameter slider against the "arms", the shoes do expand and make the drum rotate. However, I am sure a shallower angle will make things work with a lot less effort.


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## Brian Rupnow (Oct 4, 2016)

Charles Lamont said:


> Brian, I think you may have a problem with getting much force where the shoes press on the pulley. The actuating arms look to be about three times as long
> as the shoe guides. After the shoe makes contact with the pulley, any further pressure on the actuating arms will create a torque that tends to jam the shoe in its guide slot, losing a lot of the actuating force to friction. You could improve things by making the arm as short as possible.
> 
> However, It seems to me more likely that in the original device the arms are in fact levers, pivoted on the hub 'behind' the shoes. This would hugely improve the mechanical advantage obtained, and greatly reduce the chance of problems with friction within the mechanism.
> ...


Charles--I can't disagree with your physics---but---if there was a pivot anywhere in that old picture I posted, and you slid that slider in between the arms, that would retract the clutch shoes, not expand them.


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## Brian Rupnow (Oct 4, 2016)

I changed the angle on the end of that 3/4" slider to an included angle of 60 degrees instead of 90 degrees, and it made a tremendous difference. The clutch is working just as I hoped it would. You have to keep in mind that those sliding shoes only have to move about .015" to make the difference between engaged and disengaged. If they had to travel any real distance, then I'm sure they would "cock over" and bind badly. I can feel a video coming on---


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## Charles Lamont (Oct 4, 2016)

Brian Rupnow said:


> Charles--I can't disagree with your physics---but---if there was a pivot anywhere in that old picture I posted, and you slid that slider in between the arms, that would retract the clutch shoes, not expand them.



Um, no ... not if the pivot point is further down inside the pulley than the shoe.


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## Brian Rupnow (Oct 5, 2016)

This morning I took successive cuts from the outside diameter of the coned 3/4" piece until I had it down to a diameter that would just slide between the arms under slight pressure to open them wider and engage the sliding shoes with the clutch drum. This was not something that could really be calculated with any accuracy. It was purely "turn a little bit and then try it" engineering. With my model, the "ideal diameter" should have been 0.520" diameter. In actuality, it was exactly 0.500" diameter, which is pretty darned close, considering the build up of tolerances and the shape of the arms. I have provided two pictures, one showing the clutch in the "not engaged" position--The "Not engaged" position shows a gap of 0.100" between the nose of the sliding cone and the brass hub. The "engaged" position shows 0 gap between the nose of the sliding cone and the brass hub. And yes, that is a Canadian quarter laying in the foreground to give e sense of scale. Our quarter is the same size as an American quarter .


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## Brian Rupnow (Oct 5, 2016)

It doesn't always start with a pretty 3D cad model. Sometimes when I'm hashing out exactly what I'll do next, I resort to good old pencil sketches to determine the direction I will take. I will now go from this preliminary sketch to a 3D cad model where I can input all the math data to create accurate models and detail drawings from.


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## Brian Rupnow (Oct 5, 2016)

So, we end up looking like this. The panther pink pulley is driven by an o-ring drive belt from one of my engines, to turn the lineshaft. When the clutch is not engaged, the blue pulley drum just sets there and does not revolve. When the clutch is engaged, the pulley drum does turn, and will drive an o-ring belt that powers one of my "work, work, work mechanisms, probably the moving staircase.


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## Brian Rupnow (Oct 5, 2016)

Charles Lamont said:


> Um, no ... not if the pivot point is further down inside the pulley than the shoe.


Charles--You're right. I really like that idea. It would work better. Now all we have to do is find somebody who has one of the originals, have them take it apart and get some digital photos, and post them here where we can see what's inside. I have seen these in operation when I was a kid, there was a water powered line shaft sawmill about a mile from where I grew up. Unfortunately, 60 years ago I wasn't interested enough to look inside one.---Brian


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## Herbiev (Oct 5, 2016)

I am getting a strong urge to make this attachment for the Rupnow vertical engine.


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## Brian Rupnow (Oct 5, 2016)

Herbiev said:


> I am getting a strong urge to make this attachment for the Rupnow vertical engine.


Herbie--Don't rush in where angels fear to tread----You are going to have your hands full getting your first engine to run. By the time you get to that stage, I'll have figured out whether or not this clutch is going to work.---Brian


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## Brian Rupnow (Oct 5, 2016)

That's enough for today. My back hurts!! Tomorrow, I hope to make the lever mechanism that will engage and disengage the clutch.


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## Brian Rupnow (Oct 5, 2016)

-If you go back and look at reply #8 you will see that on the original line shaft clutches, the tapered bits on the end of the arms have a thread in them. I think that was how they adjusted to compensate for wear and to make sure that both arms extended equally. Of course, here in "Model world" I don't have to be quite as concerned with wear. Now that I have actually made the arms, I see that I could have incorporated a threaded fastener into them to provide the same service, however, as in most things I build, this is my 'prototype", even if I never build another one. Before this week, I always wondered about this type of clutch and how it actually worked. But----There are about a million mechanical things floating around in the back of my mind that I kind of wonder about, but unless I make a conscious effort to recreate the design and build one myself, they are only vague thoughts. One thing I can say for this clutch, based on my experience so far---There isn't much "between" to this clutch. It's either ON or its OFF. Probably it transfers less shock to the driven machinery than a dog clutch would, but there isn't a whole lot of "slippage". There doesn't seem to be any replaceable lining on the friction shoes either from what I can see in the photograph in post #8.


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## Brian Rupnow (Oct 6, 2016)

My clutch is all finished and seems to work well. If I can find the energy to get things set up, I'll post a video. I think since I already have my Kerzel hit and miss out on the bench I will use it as a driver, thru the newly made clutch, to the steel ball elevating staircase. If everything works as I hope, I will put up a link to the drawings.-- Most line shaft clutches I remember seeing had the line shaft overhead, and a long handle that hung down for the machine operator to pull to engage the clutch. Of course my memories are from sawmill stuff in the 1950's.---Brian


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## mjonkman (Oct 6, 2016)

Brian

if your bored and want to go for a few hour drive down towards Sarnia, head over to Petrolia On and check out Baines Machine and Repair. He still runs almost his entire shop using overhead flat belt system.

http://www.hardoilnews.com/21863676

and

http://lostlambton.proboards.com/thread/33

Click on the second picture or the link below

http://s209.photobucket.com/user/lost_lambton_found/media/industries/65f81eb6.jpg.html

I used to hang out there a bit in my early teens. He's good friends with my dad but he probably wouldn't remember me (or at least I wouldn't expect him to). I stopped in a few years back when I was home and just stood and took in the whole overhead system again. So cool.


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## Brian Rupnow (Oct 6, 2016)

Well, I'm all set up and ready to go. I realized that the drive wasn't going to work on the Kerzel, because the gas tank was in the way, so I stuck the Rupnow Vertical in there instead. However, I've ran into technical difficulties. My clutch which worked so good when testing it in the lathe is letting me down in "actual circumstances". The coned hub which the lever moves back and forth is supposed to turn freely, so that when it is engaged it doesn't see any load from the lever. When engaged it is supposed to turn with with the central hub and arms. For some reason that isn't happening, and it is creating drag where there shouldn't be drag, and making my drive belts slip. I'm too  tired to fight with it anymore today, so I am going to clean up, go upstairs, and drink wine.


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## Brian Rupnow (Oct 6, 2016)

Right now I'm not too impressed with my clutch. In all my years in engineering I have never had particularly great results with sliding mechanisms. It seems that nothing has fundamentally changed. Pivots rule!! I will make one more stab at making my clutch work tomorrow. if I don't have immediate success, there is going to be a design change. I haven't lost all that much if I go to a total design change. The frame and pulley have the most work in them, and that will stay. I have to think on what to do next.---Brian


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## Brian Rupnow (Oct 7, 2016)

So there we have it--An operating line shaft style, expanding shoe drum clutch. This was not a great effort in terms of engineering, as I followed a design from long ago. The problems came in reducing everything in size to end up with a 1/4" shaft and a 1.7" outside diameter drum. The original full sized clutches had better proportions, and the contact surfaces on the end of the arms which the sliding cone bears against to operate the clutch had threaded ramps, which could be used to set the pressure on the shoes, and equal travel on each arm. My initial attempt to operate this clutch yesterday failed because there were too many points of "binding" in all of the mechanicals. I took it all apart this morning, added a few clearances to critical areas, and made a new coned slider out of O1 material which I flame hardened. That seemed to do the trick, and as the video shows, the clutch does operate.
[ame]https://www.youtube.com/watch?v=y5m5SrYTjFk[/ame]


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## Herbiev (Oct 7, 2016)

Great video Brian. Really love the "staircase" too.


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## michael-au (Oct 7, 2016)

Interesting project
Thank you for sharing, nice video

Michael


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## Brian Rupnow (Oct 7, 2016)

Having built one line shaft type clutch, which works, but is far from perfect (I hate sliding parts), I have taken some advice from Charles Lamont on HMEM and reworked the design so the clutch shoes are operated by pivoting levers. The shoes still slide in a milled rectangular slot, but the arms which operate the levers are pivoted at one end, and have an adjustment screw at the other end to set the pressure they exert on the inside of the drum, and the two separate sliding shoes can be equalized. Force is transferred from the pivoting arms via a cross-pin which transfers movement to the sliding shoes. The overall diameter is the same as the clutch which I just built and made the video of. I am quite excited about this design, and probably will make a clutch to this design in the coming weeks.


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## Belugawhaleman (Oct 7, 2016)

I've been wanting to make a clutch of similar design. Thanks for posting.


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## Brian Rupnow (Oct 8, 2016)

This is the same pivoting style clutch with the shoes maximized for thickness and for width. this gives more than twice as much shoe contact area with the inside of the drum.


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## Brian Rupnow (Oct 8, 2016)

Okay--Hang onto yer pants--Here we go!!!---


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## Brian Rupnow (Oct 8, 2016)

And a couple more--


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## Brian Rupnow (Oct 9, 2016)

I have a much better feeling about this new pivoting clutch. The two main outer shells that bolt together and the adjustable swinging arms are finished. Probably I will make the sliding shoes next.


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## Brian Rupnow (Oct 9, 2016)

So, after a full days work, this is the new clutch in which the shoes are expanded by pivoting levers. I have one "in process" shot of the shoes being machined as one piece from a 1 1/2" diameter piece of steel. They were fitted and split into two pieces after all of the machining. It works so smoothly I had to make a movie of it.


 
[ame]https://www.youtube.com/watch?v=szABU_9WM4o&feature=youtu.be[/ame]


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## Brian Rupnow (Oct 10, 2016)

Charles Lamont--If you are following this thread, thank you for your suggestion about the pivots in the mechanism. I have rejigged the mechanism to what you suggested, and it really does work much better than the way I originally had it.---Brian


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## Brian Rupnow (Oct 10, 2016)

And a short "explanation" video of the fully assembled clutch----
[ame]https://www.youtube.com/watch?v=lGXQXf7ZGSY&feature=youtu.be[/ame]


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## Brian Rupnow (Oct 10, 2016)

Final "run" video of clutch version #2
[ame]https://www.youtube.com/watch?v=hPuQ2R0E8Ys&feature=youtu.be[/ame]


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## Cogsy (Oct 11, 2016)

Think I'll probably have to make one. I do like the idea of being able to put these engines to work.


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## Charles Lamont (Oct 11, 2016)

Brian Rupnow said:


> Charles Lamont--If you are following this thread, thank you for your suggestion about the pivots in the mechanism. I have rejigged the mechanism to what you suggested, and it really does work much better than the way I originally had it.---Brian


Brian, you are welcome. I am pleased to see it has kept you out of mischief for a couple of days.


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## ShopShoe (Oct 11, 2016)

Bravo Mr. Rupnow

I remember your other clutch (Last Year?) and I believe that I like this one better.

The ball elevator is on my "someday gotta build this" list and now I think I gotta build the clutch, too.

Regards, and Thank You again,

--ShopShoe


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## Brian Rupnow (Oct 11, 2016)

This was a fun project, even if the first attempt gave less than stellar results. I really like the second, final version. I was so burned out on machining from my July thrash on the vertical engine that I haven't wanted to do any machining until last week when this came up. The total duration of this project was 6 days, including the first version which I wasn't really happy with. It is getting more and more difficult to find projects that interest me. I think I'm up to 23 or 24 finished engines now, 12 of which are i.c. and 11 or 12 that are steam/air powered. I'm tired of building engines. I want to build another interesting machine to drive with my engines. Currently I have the slinky machine, the bubble blowing machine, the ball elevator that appears in the video, a sawmill, a buzz saw, a wood splitter, a piston pump, a gear pump, an oil well "grass-hopper" pump, a pile driver, and a semi-complete marble automation. I think that perhaps I will design and build a "walking beam conveyor" for my next project. They are fascinating to watch, and just different enough to be interesting.


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