# What kind if splined shaft is this ?



## Anatol (Aug 25, 2018)

I wasn't sure where to put this question. 
I have a (mid 1970s American) winch/windlass - company is long gone. It has an unusual splined shaft (It's ~ 1" OD, inner shaft is ~ 0.75") and  the splines are semicircular in cross section. Has anyone seen one like this, know the name it goes by or went by or in what context it was mostly used? I'm hoping to find or make a mate/socket for it. 
As for making a socket, I'm guessing the best approach would be to drill the six holes on the circumference of the ID circle, then bore the ID. Then harden. 
thanks!


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## Herbiev (Aug 25, 2018)

Looks like a PTO ( power take off) shaft from a tractor.


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## Anatol (Aug 26, 2018)

Thanks for the tip. I googled around. Tractor PTOs are that shape but tend to  be 1  1/8 or 1  3/8 -bigger.But that led me to the right terminology for further searches.  " 1 inch 6 spline coupling" is getting me closer, but haven't seen any half round spline shapes.


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## BaronJ (Aug 26, 2018)

Hi Anatol, Guys, 

That spline was done on a horizontal mill with a shaped cutter.  Simply held between centres and rotated for each pass.  That would have been done with one cut for each spline.


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## goldstar31 (Aug 26, 2018)

As Baron says 'female' on  horizontal mill but a shaper to do the 'male'

Personally, I'd like to see it done.

Cheers

N


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## Barnbikes (Aug 26, 2018)

Probably had something like this on it.

https://www.steinertractor.com/ABC1...NUv_arpzuMebsl7-g2AXLgVTHav5qtBwaAnR7EALw_wcB


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## BaronJ (Aug 26, 2018)

Hi Norman,

Haven't you got that the wrong way round !  You would do the male part on a horizontal mill and use a shaper or slotter to do the female part.


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## goldstar31 (Aug 26, 2018)

BaronJ said:


> Hi Norman,
> 
> Haven't you got that the wrong way round !  You would do the male part on a horizontal mill and use a shaper or slotter to do the female part.



Comes from being born in a thunderstorm.

My excuse, anyway

N


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## Chiptosser (Aug 27, 2018)

Anatol,
I would try it your way, should work fine.


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## BaronJ (Aug 27, 2018)

Hi Anatol,

I just realised that I didn't answer your last question.  Yes !  Drilled holes on pcd, bore and file as needed.

If you make it a good fit you probably wouldn't need to harden it.


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## DJP (Aug 27, 2018)

And if the fit is not tight use some green Loc-tite for shafts. You will need to heat it for removal.


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## nel2lar (Aug 27, 2018)

looking at the splines, I've never seen on as such but could it be a badly worn spline shaft? The spine shafts are made that way for ease of disconnect. Farm machinery use it as a prime universal way to drive all their equipment, except for the modern hydraulic drives. I believe a straight female splined should work fine. 
Nelson


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## Anatol (Aug 27, 2018)

Barnbikes said:


> Probably had something like this on it.
> 
> https://www.steinertractor.com/ABC1...NUv_arpzuMebsl7-g2AXLgVTHav5qtBwaAnR7EALw_wcB



interesting, thankyou! - but that is a 10 spline and the splines are square/trapezoid section


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## Anatol (Aug 27, 2018)

nel2lar said:


> looking at the splines, I've never seen on as such but could it be a badly worn spline shaft? The spine shafts are made that way for ease of disconnect. Farm machinery use it as a prime universal way to drive all their equipment, except for the modern hydraulic drives. I believe a straight female splined should work fine.
> Nelson



No, the shaft not worn, it was made that way and is very clean. Aside from this being a practical problem for me, I'm trying to understand why the designer made the splines that profile. It is a high torque low speed application. A gearbox or gear head DC motor would have driven the shaft. But like you guys, I've never seen a splined shaft like it.


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## Anatol (Aug 27, 2018)

So - Chiptosser, BaronJ and all,
"Drilled holes on pcd" this is where I reveal my long experience in making but learner status in precision machining. Lets say I want to make a tubular female-female coupling to go on a motor shaft with a keyway. Say 5/8 shaft. Let me check an order of operations with you - 

I'll start with a piece of  1.5" dia bar, say 3" long (sorry for imperial measurements).

square up ends and mark centers on lathe
clamp piece in rotary table on mill
drill my 6 holes on pcd 1.5" deep
bore or drill 5/8 hole straight through
bore or drill 1" hole 1.5" deep, cutting away half of pcd holes.

Now for the internal keyway on the motor end.
How do you cut an internal keyway?  - found it in a nice vid here (gotta love youtube)

amusingly called 'long boring process' - very apt
so you just scrape it out! (using a boring bar)

And of course, drill and tap for 2 or 3 set screws. 

sound about right?


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## Cogsy (Aug 27, 2018)

You don't want 3 set screws - 2 at 90 degrees is best. For the internal keyway, the 'normal' way is to use a keyway broach, but for one-offs they're expensive so the scraping method is used a lot, usually employing a cut-off blade rather than a boring bar.

I don't recommend gloves on the lathe (or any such rotating machinery) like the guy in video is using. They might keep your hands clean but they could cost you a finger, or worse. Not worth the risk in my opinion.


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## BaronJ (Aug 28, 2018)

Hi Anatol,
I made this for my mill table drive, it fits directly on the leadscrew in place of the handwheel.





And this is the tool that I made to cut that keyway.  The HSS toolbit is located in a slot milled down one side of the round shaft.  The shaft was chosen to be a good but loose fit in the bore of the workpiece.  The idea being that it would guide the cutter and reduce any deflection.  In practice the tool was sufficiently rigid for me to use it to cut several other 4 mm keyways into some steel gears, one of which was a stainless steel one.




The actual cutter is a length of 4 mm square tool steel with the end ground almost flat.
I originally used the tool in the lathe saddle to push it through the workpiece whilst it was held in the chuck.




In this picture you can see how I used a M2 hex socket grub screw to adjust the cutter depth.  This picture was taken before the tool bit was ground into a cutting edge.




This picture shows how I secured the tool bit and how it allowed movement.


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## nel2lar (Aug 28, 2018)

Anatol
I do not see any reason you could not take and use a wider tool and grinding the round profile into it and when pushing it through the hole cut the sides of two teeth at a time rotating 6 or 8 times to produce the coupler you need. Keep us up on the progress.
Nelson


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## DJP (Aug 29, 2018)

What's missing in this thread is the final use of this winch. Does it even need a spline coupler to fulfill it's new task of coupling to a drive source? Perhaps welding on a flexible coupler will get the job done for the life of the winch. Or is this a restoration project that needs to be original?

Just curious.


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## Anatol (Aug 29, 2018)

BaronJ said:


> Hi Anatol,
> I made this for my mill table drive, it fits directly on the leadscrew in place of the handwheel.
> .



Thankyou fro the pics, that's a nice piece of toolmaking!


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## Anatol (Aug 29, 2018)

nel2lar said:


> Anatol
> I do not see any reason you could not take and use a wider tool and grinding the round profile into it and when pushing it through the hole cut the sides of two teeth at a time rotating 6 or 8 times to produce the coupler you need. Keep us up on the progress.
> Nelson



Interesting idea, thanks


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## TonyM (Aug 30, 2018)

It's called an involute spline. Made to reduce stress points and give greater strength than a square form spline.
This half round form is probably a Wildhaber Novikov gear


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## bazmak (Aug 30, 2018)

Could the male and female shafts be drilled together and when taken apart pins fitted to the male
to form the splines ???


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## TonyM (Aug 30, 2018)

A bit of light reading for anyone interested. https://ac.els-cdn.com/089571778990...t=1535636725_ab67e02e4098ef7f32403fc735c5dde9


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## J Harp (Aug 30, 2018)

Looking closely at the splined shaft it appears the spline was first cut to depth with an end mill, then a wheel type cutter was run down the slots to form the profile.
I'm wondering why you would put set screws on a splined coupling? Seems to me that would defeat the purpose of the splines.
I'm no engineer, just a tinkerer, but my understanding is the reason for a splined connection is to provide a positive drive, while allowing a limited axial movement or some leeway in axial placement.


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## BaronJ (Aug 30, 2018)

Hi Anatol,

Thank you for the complement.

Just for the record:


> I'll start with a piece of 1.5" dia bar, say 3" long (sorry for imperial measurements).
> 
> square up ends and mark centers on lathe
> clamp piece in rotary table on mill
> ...



Is exactly how I would do it.


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## Anatol (Aug 30, 2018)

TonyM said:


> It's called an involute spline. Made to reduce stress points and give greater strength than a square form spline.
> This half round form is probably a Wildhaber Novikov gear



Thankyou! A name for it. Makes sense, this is a high torque low rpm application. But I think, strictly speaking, a splined shaft is a not a gear, for obvious reasons - one part - the coupling - doe not rotate around the other.


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## nel2lar (Aug 30, 2018)

I read that article from WILDHABER-NOVIKOV GEARS APPLICABLE. It make a lot of sense in his theory but I wonder why his was not kept because of load and stress. Somethings we just do not understand.
Nelson


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## nel2lar (Sep 7, 2018)

Anatol
I think the document was written in Europe and the lingo is differ than ours. I remember reading the word pinion and that is something in clocks.
Quote:
 Root bending stresses of *pinion* and gear with different loading positions have been analyzed. Effects on root stresses due to variations of fillet radius and normal pressure angle of *pinion* have also been investigated.

I believe it was a good coupler for its application. It is different for sure.
Nelson


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## Wizard69 (Sep 11, 2018)

It is pretty common in mechanical drives to refer to the small gear as the pinion.  Thus the term rack and pinion where the rack has an infinite diameter.


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## john_reese (Oct 10, 2018)

Anatol,
I think your method of drilling holes on the pcd and boring out he center is workable.  Ig you make he female spline long enough you can eliminate the need for hardening.  Most tractor PTO shafts and couplings I worked with were unhardened.


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## goldstar31 (Oct 13, 2018)

[


Anatol said:


> Thankyou fro the pics, that's a nice piece of toolmaking!



Forgot to mention that I was in Edinburgh a fortnight ago. Nice example of the fluting in Rosslyn Chapel next to the Apprentice's Pillar. That has the mystical helix carved in it.

N


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## BWMSBLDR1 (Oct 14, 2018)

I have seen something very similar on a 1920's Miller 8 race car engine. nuts were circular with 4 semicircular cuts on the periphery. The socket was a cylindrical hole with 4 hard pins set into the body projecting halfway into the hole. Why it was don this way I do not know!   Bill in Boulder CO USA


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## goldstar31 (Oct 14, 2018)

BWMSBLDR1 said:


> I have seen something very similar on a 1920's Miller 8 race car engine. nuts were circular with 4 semicircular cuts on the periphery. The socket was a cylindrical hole with 4 hard pins set into the body projecting halfway into the hole. Why it was don this way I do not know!   Bill in Boulder CO USA



The earliest gears were wooden wheels -with round wooden pegs to intermesh with others.


Once the average tutor struggles to get students to understand Archimedes, everyone has lost interest .

Once of the best bits of machinery was the Gutenberg printing press  and made with wooden pegs as gears- some like what the topic started out as



Ah well?

Norm


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