Author Topic: Shay gears (parallel depth bevel gears graphical tutorial)  (Read 3974 times)

Online Dan Rowe

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #15 on: September 18, 2020, 07:59:23 PM »
Thanks to Andrew, I now realize that I did not use the correct tooth curve for all the 3D bevel gears I drew and had made by Shapeways and other printed sources. They seem to run fine so I will use some of them because they are in the shop. Now that I understand Tredgold's approximation I know which gear curve to choose.

Here is a link to an explanition of Tredgold's approximation and it is still hard to follow and I understand the theory. There is also some of the early bevel gear machinery that dates to around 1910 in the US. I have copied the photos for this thread.
https://archive.org/details/bevelgearing00flanrich/page/32/mode/2up?q=Machinery%27s+Reference+37



This is a small Gleason template bevel gear planer. The template for finish cutting uses Tredgold's approximation.



This one is a specilized milling machine for automatically cutting bevel gears. It uses a special thin bevel gear cutter and the small ends of the teeth will have to be filed to a bit more curve, just like doing this on a standard milling machine and an index head.


Bilgram's bevel gear generator a modified shaper.



Gleason's bevel gear generating machine. It uses two rotary cutters to cut both sides of a single tooth at the same time. This is much quicker than a Bilgram machine.

Cheers Dan

 

ShaylocoDan

Online crueby

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #16 on: September 18, 2020, 08:22:14 PM »
Love the pictures of the old machines - be a fun model to make...! 

Online Dan Rowe

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #17 on: September 18, 2020, 10:44:31 PM »
Chris, Lima made the gears here is a photo of the gear testing machine.



The gear machines at Lima.



The machine on the left with the upside down bull gear is a radial planer or milling machine to face and drill the gear flange. The machine on the right with the operator is the gear cutting machine. I am not certain what principle the machine uses but I am leaning to a Gleason template planer. If anyone can identify the machine or even point out the operating principle I would be pleased to know.

Now those machnes would make cool models.

Cheers Dan
ShaylocoDan

Offline jadge

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #18 on: September 20, 2020, 11:29:48 AM »
Interesting pictures, thanks for posting.

In the picture of the erecting shop the machine on the left looks like a vertical borer, not sure it has a drilling capability? The machine on the right looks like a vertical borer too, although I don't know what the gear train is for. It could be for machining conical surfaces as opposed to simple facing and cylinders?

With regards to the Gleason bevel gear generator I have seen one in action. I don't recall it using rotary cutters? It has two tools that reciprocate, one cutting and one being retracted alternately. As the cut progresses the gear being cut rotates and the whole cutter head also rotates about the axis of what would be the mating gear. So the cutters stay in sync with the tooh being cut, but effectively move outwards. As Dan says it is quicker than other types of machine as it cuts both sides of a tooth in each pass. It generates the tooth form as a series of lines in a similar way to hobbing of spur gears.

Andrew

Offline PJPickard

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #19 on: September 20, 2020, 12:46:35 PM »
Dan, great picture of the Lima shop! Where did you locate that?

Offline Millwright

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #20 on: September 20, 2020, 08:43:22 PM »
The machines look to me like early Webster and Bennett double column vertical borers.
John.

Online Dan Rowe

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #21 on: September 20, 2020, 09:00:48 PM »
I found an image of the other side of a Gleason template bevel gear planer.



Now the templates can be seen, there are curved templates for both sides of a tooth and a straight template for the roughing cut. These are all bolted to a plate that can rotate each template to the top to guide the cam follower.

This is a 24 inch machine which is big enough for gear #17 but not the larger Shay gears. I did find a larger Gleason planer large enough to do all the Shay gears and it looks nothing like the one in the Shay shop.



Gleason Model 54 Date built 1939

"Specification:
Straight Bevel Gear Planner, Model 54 capable to Produced Bevels up to 60"-1, 524 mm with a Face Width 14"-55.6 mm, comes equipped with a full set of change gears, full set of 1430 and 20 P.A. Forms, tool gauge, Arm Rest, assorted gear arbors, coolant pump and under power for inspection."

Back to the Shay shop......
The machine on the left with the gear flange getting cut true is a vertical boring mill sometimes called a vertical boring lathe. Most folks that have researched US railroad shops have heard of the Niles Tool Works of Hamilton Ohio. I knew they were not far from Lima so I looked for Niles vertical boring mills. I was hoping to find the half circle opening that is on the base of both machines but this was not the case.

Here is the smallest Niles vertical boring mill.


There is a list of special attachments for a Niles boring mill these are a cylinder boring bar, a slotting and key-setting attachment, a pulley turning attachment, and a thread cutting attachment.

The links are catalogs the first one has engravings and the second one has photographs, very interesting stuff.
Niles Tool Works Hamilton Ohio 1891
https://babel.hathitrust.org/cgi/pt?id=coo1.ark:/13960/t2c82vp12&view=1up&seq=1
https://babel.hathitrust.org/cgi/pt?id=wu.89089664148&view=1up&seq=7

I was think I was wrong about the machine on the left drilling the flange. The flange has to be drilled and two radial keyways need to be cut. These operations must have used a normal vertical milling machine unless there was a seperate attachment that could be added.

Here are both gears to compare.


The one with the gear facing up has a rough cast flange. This must mean that the teeth were cut first then the second machine faced and turned the diameter of the flange.

Cheers Dan
ShaylocoDan

Online Dan Rowe

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #22 on: September 20, 2020, 09:15:30 PM »
Dan, great picture of the Lima shop! Where did you locate that?

The photos are from George Kadelak's Shay Photo CD.
https://shaylocomotives.com/

For some unknown reason my name is not on the front page as a Shay contributor you have to go here to spot my work on the mechanical database.
https://shaylocomotives.com/links/Links.htm

Cheers Dan
ShaylocoDan

Online crueby

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #23 on: September 20, 2020, 09:21:07 PM »
There are a couple more photos here, on Gleasons website, towards the bottom of the page, along with a picture of the Gleason Works - they are cross town from me. A friend of mine works there, have to see if he knows of any other picture sources...


https://www.gleason.com/en/operations/the-gleason-works-rochester-ny-usa/this-is-our-story



Online Dan Rowe

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #24 on: September 20, 2020, 10:23:19 PM »
Chris the history of the Gleason works is not really clear to me.

Interesting pictures, thanks for posting.

With regards to the Gleason bevel gear generator I have seen one in action. I don't recall it using rotary cutters? It has two tools that reciprocate, one cutting and one being retracted alternately. As the cut progresses the gear being cut rotates and the whole cutter head also rotates about the axis of what would be the mating gear. So the cutters stay in sync with the tooh being cut, but effectively move outwards. As Dan says it is quicker than other types of machine as it cuts both sides of a tooth in each pass. It generates the tooth form as a series of lines in a similar way to hobbing of spur gears.

Andrew

James Gleason son of William Gleason patented a bevel gear generator with two rotary cutters in 1898 US patent 605249 June 7. 1898. This machine has two rotary cutters acting on both sides of a tooth.
https://patents.google.com/patent/US605249A/en?oq=605249

This is not the same machine as the image of the Gleason bevel gear generator I posted. I can see two cutters in the image the top one is closer that the lower one.

Here is an image showing the operating principle with a confusing date of 1905.



Cheers Dan
ShaylocoDan

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #25 on: September 20, 2020, 11:07:58 PM »
Dan, my friend who worked there is getting some info for me, he has a video and booklet that was produced ror the Gleason company 100 year mark. I'll put up more when I get it...

Online Dan Rowe

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #26 on: September 21, 2020, 01:45:27 AM »
Hi Chris that might fill a few holes....

I reread my copy of Studies in the History of Machine Tools by Robert S. Woodbury. The first section is the History of the Gear Cutting Machine.

Pg. 87
"Two other describing-generating machines deserve mention.... One is described in an Austrian patent of 1879 issued to C. Dengg & Company of Vienna.35 This machine (Fig. 31) generates only epicycloidal teeth and only bevel gears. The tool is guided along an element of the tracing curve, but the machine could not form hypocycloidal flanks. It is shown here as an example of the highly specialized types of gear-cutting machines sometimes developed."

"35. Austrian Patent No. 657 of July 1879."



I had dismissed this machine because of where it was built, but the machine in the Shay shop has a stricking similarity to the patent drawing. The vertical shaft with 3 bevel gears is on the top and there are a bunch more gears but patent drawings often differ from the actual machine. The Shay gears were epicycloidal bevel gears so that matches. I am not sure that Gleason machines ever made epicycloidal gears.

I tried to find the patent and Dengg & Company but did not find anything. I am now thinking that the photo is very possibly the extremely rare Dengg bevel gear machine.

Cheers Dan
« Last Edit: September 21, 2020, 02:23:40 AM by Dan Rowe »
ShaylocoDan

Offline Don1966

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #27 on: September 21, 2020, 01:54:20 AM »
Hey Dan, have you ever thought of modeling one of these machines. Making it a working model. Bet it would make a great project. Just me rambling.....


 :cheers:
Don

Offline john mills

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #28 on: September 21, 2020, 10:08:16 AM »
Hi Dan
I'm following with interest i have only been told of
Gleason type generating machines using 2 reciprocating cutters wondering how they worked .
interesting you mentioned  nile vertical borer   i new some one how had one a 48"  table in his shed at home

latter i had a job were they were using one .I said at the time i' new some one that had one of these .latter when i
saw that person he confirmed it was his machine he had changed it for a bigger machine.
  How small did they make these bevell gear generators  ,in stead of a model  you could probably just build a small one.that would be an interesting project.
       John

Online Dan Rowe

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Re: Shay gears (parallel depth bevel gears graphical tutorial)
« Reply #29 on: September 22, 2020, 10:44:21 PM »
John, wow they guy who had a Niles vertical boring machine only to trade up to a larger machine does not have a shed.... he has a machine Palace  :cartwheel:

I forgot to mention that the Niles Works build 31% of the engines for Liberty ships. I have only seen one which is at the Merchant Marine Academy where it was no longer part of the curriculum when I was an engineering cadet but we asked and asked until they let us run it on steam. That was very cool to see.

I quoted everything Woodbury had to say about the Dengg machine but the sentance "The tool is guided along an element of the tracing curve, but the machine could not form hypocycloidal flanks." is really a bit confusing to say the least.

To make sense ot that statment we need to know how a epicycloidal or cycloidal gear is constructed. Here is a link to a few very short video clips that show how construct a cycloidal gear.

https://www.tec-science.com/mechanical-power-transmission/cycloidal-gear/geometry-of-cycloidal-gears/

Be sure to watch the last one also to learn how an involute curve the more modern gear curve relates to a cycloid gear curve.

Now it should be clear why Woodbury's statment is troubling. The curve above the pitch line or addendum is an epicycloidal curve and the dedendum curve is a hypocycloidal curve. So Woodbury is saying that a Dengg machine could not cut the lower part of the gear. Well that would make it a very useless machine.

The special case where the rolling circle is half of the pitch circle giving a straight line got me thinking....what if the dedendum was a straight line or a nearly straight line?



The tooth form is shown on the pinion drawing and the dedendum curve is nearly straight it only varies 0.011" from straight. I checked my old gear books and the construction looks like it is Grant's odontograph. I have this method in at least two books so I will go through the example drawings then see if it works on #17 pinion. If it works I can draw the bull gear tooth using the same method to see the dedendum curve and see how straight it is.

The Dengg machine is really a powered Spirograph that cuts bevel gears!!!!

Cheers Dan
ShaylocoDan