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Supporting => Tooling & Machines => Topic started by: Vixen on September 28, 2018, 06:02:18 PM

Title: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 06:02:18 PM
Can anyone help, please?

I am trying to find some 0.6 module involute cutters to cut the gears for the Jupiter's magneto. The gears in question have 63 teeth and 28 teeth, giving a 2.25 to 1 reduction.

I ordered the two cutters via Aliexpress, they have not arrived after 6 weeks, so we have a payment dispute in progress for non delivery. My problem is, the only places I can find suppliers are also with Aliexpress and I don't want to go down that route again.

Do any of our MEM members have access to 0.6 module involute cutters and would it be possible to borrow them for a few days to cut my 63 teeth and 28 teeth gears. One gear is in Delrin and the other in soft mild steel EN1.

I have tried to identify other gear standards but none match the required tooth count and PCD, so 0.6 module is the only option

Thanks for looking

Mike


Title: Re: 0.6 module involute cutters
Post by: Stuart on September 28, 2018, 06:11:29 PM
Mike

Pour yourself a good sized slug of glenfarclas 105 full cask strength single malt before looking

http://www.tap-die.com/contents/en-uk/d175_Module_MM_Involute_Gear_Cutters.html


Note I am not in any way reponsible for any medical problems ,choking throwing toys out of pram or spitting out of dummies  :stir:

Stuart
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 06:17:01 PM
Hi Stuart

Thanks for the laugh. I did find that one. As you probably guessed, I am not that desperate.

Cheers

Mike :facepalm: :facepalm:
Title: Re: 0.6 module involute cutters
Post by: wirralcnc on September 28, 2018, 06:19:50 PM
Mike

Since they are silly money. What about hpc gears they have what you want at a fraction of the cost. I will have a look in work on tuesday see if we have 0.6 mod cutters.

Robbir
Title: Re: 0.6 module involute cutters
Post by: Dan Rowe on September 28, 2018, 06:21:02 PM
Here is a source I just located:
http://www.ctctools.biz/hss-involute-module-gear-cutter-set-8pcs-h97/

Dan

Title: Re: 0.6 module involute cutters
Post by: Stuart on September 28, 2018, 06:25:04 PM
Thatís ok Mike

Guessed you had seen that it came up to easy

But we simply to please


Have you seen a program called gearotic ( itís ok done by art of mach3 fame )

It lets you put in the shaft spacing tooth counts and lets you check for fits etc

If you donít have it please post the shaft centres and I will run it though to see if any modest price cutters will work

But you could be making a two button form tool to cut the cutter yourself


Have fun in you quest to find the unicorn or pot of gold

I will tune up my Google fu and keep a look out

Stuart
Title: Re: 0.6 module involute cutters
Post by: Jo on September 28, 2018, 06:30:23 PM
I can do the wrong profile  :-\

Jo
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 06:35:38 PM
Thanks Jo

Getting closer, but no cigar


Mike ;)

Title: Re: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 06:39:35 PM
Here is a source I just located:
http://www.ctctools.biz/hss-involute-module-gear-cutter-set-8pcs-h97/

Dan

Thanks Dan.  Thats a possibility

Mike
Title: Re: 0.6 module involute cutters
Post by: crueby on September 28, 2018, 06:42:18 PM
Here is a source I just located:
http://www.ctctools.biz/hss-involute-module-gear-cutter-set-8pcs-h97/ (http://www.ctctools.biz/hss-involute-module-gear-cutter-set-8pcs-h97/)

Dan

Thanks Dan.  Thats a possibility

Mike
I have several sets from ctc, used them a lot for brass and aluminum gears. I use Gearotic for quick calculations of gears, also the Ivan Law gear book.
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 06:48:00 PM
Mike

Since they are silly money. What about hpc gears they have what you want at a fraction of the cost. I will have a look in work on tuesday see if we have 0.6 mod cutters.

Robbir

Thanks Robbie.

Yes HPC can provide an off the shelf 28T gear in steel at a reasonable price, but the Delrin 63T is deeply dished so would need to be a one off special. Let's hope my luck is in on Tuesday

Cheers

Mike
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 07:02:38 PM

Have you seen a program called gearotic ( itís ok done by art of mach3 fame )

If you donít have it please post the shaft centres and I will run it though to see if any modest price cutters will work

Have fun in you quest to find the unicorn or pot of gold

Stuart

Thanks Stuart and Crueby

I don't have Gearotic but I have checked for alternatives elsewhere. but not found anything yet. 43DP would be close but I ain't going to find those cutters anywhere. :ThumbsDown: :ThumbsDown:

The gear details are 63t 0.6 module 37.8 PCD, and 28T 0.6 module 16.8 PCD, shaft centres are 27.3 mm.

Cheers

Mike

It would be great if there were an affordable alternative
Title: Re: 0.6 module involute cutters
Post by: Jasonb on September 28, 2018, 07:12:58 PM
Full set on e-bay from Germany, Probably a bonded warehouse for far eastern products but £55 the set

https://www.ebay.co.uk/itm/Involute-Gear-Cutters-Module-Milling-20-gear-cutter-0-6-Bis-6-0-HSS-udssr/183330424887?hash=item2aaf584837:m:mK-F2WVK3uuT-81QVuNLuEA
Title: Re: 0.6 module involute cutters
Post by: Stuart on September 28, 2018, 07:13:12 PM
I will run it though tomorrow if Chris does not beat me to it as my only windoze thingy is in the workshop , itís all Mac in the house
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 07:17:04 PM
Full set on e-bay from Germany, Probably a bonded warehouse for far eastern products but £55 the set

https://www.ebay.co.uk/itm/Involute-Gear-Cutters-Module-Milling-20-gear-cutter-0-6-Bis-6-0-HSS-udssr/183330424887?hash=item2aaf584837:m:mK-F2WVK3uuT-81QVuNLuEA

Hello Jason,

Yep, I found that one as well.  Actually, they were made in the USSR

If you read the small print the cutter which does 63t is missing from the set. About as much use as a chocolate teapot.

Cheers

Mike
Title: Re: 0.6 module involute cutters
Post by: Stuart on September 28, 2018, 07:29:48 PM
Mike

Could not resist boss is watching the soaps

Your calls are spot on DP is 42.33 no hope there

The rest of your calls are correct for .6 mod at that tooth count and shaft spacing


Hope you find some at the right price but I will keep looking
Title: Re: 0.6 module involute cutters
Post by: Jasonb on September 28, 2018, 07:39:25 PM
Mike, can you not make your own cutter on the CNC lathe which should be easier than mucking about with buttons. Or what about milling a single point cutter, as it is only going to cut Delrin it does not need to be HSS
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 07:49:47 PM
Hello Jason

Yes, That makes sense, I could mill or turn a single point cutter in Silver steel then harden it.

Do you know where I can find the tooth profile data for 0.6 module.?

There is something in Chapter 12 of Ivan Laws book. I will look that up and see if it helps

Cheers

Mike :ThumbsUp: :ThumbsUp:
Title: Re: 0.6 module involute cutters
Post by: Dan Rowe on September 28, 2018, 08:13:15 PM
Mike,
Here is a dfx file of the mod .6-63T gear for the cutter profile. I used Gear Wheel Designer to generate the gear.

Dan
Title: Re: 0.6 module involute cutters
Post by: Jasonb on September 28, 2018, 08:17:10 PM
Yes Ivan laws book will give the radius and ctrs of the two arcs to form the cutter.
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 08:23:41 PM
Mike,
Here is a dfx file of the mod .6-63T gear for the cutter profile. I used Gear Wheel Designer to generate the gear.

Dan

Hello Dan

Thanks for looking into this for me. Unfortunately I cannot open the .DXF  file you sent. I think my AutoCAD is too old. Can you resend as a R12 DXF file?

Cheers

Mike
Title: Re: 0.6 module involute cutters
Post by: Dan Rowe on September 28, 2018, 08:43:18 PM
Mike, I do not have Autocad. The only other version I can generate is dwg which I think is even later. I added that and maybe some other reader can help with the conversion. I could also convert to Aibre format if that would work.

Dan
Title: Re: 0.6 module involute cutters
Post by: Jasonb on September 28, 2018, 08:48:20 PM
Mike this is what I get from Ivan's book using 42.33DP for the 55-134T cutter, you may want to check my figures Both metric and imperial sizes there

If you want to draw the gear then load the free Fusion 360 as there is a gear generator in that.
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 08:51:34 PM
Hello Dan and Jason,

Thanks for your inputs. I will work away at this tomorrow. I think I am very close now

Cheers

Mike
Title: Re: 0.6 module involute cutters
Post by: Zephyrin on September 28, 2018, 09:40:19 PM
Here is a brief summary of the method I use to make the tool to cut gears.

You have simply to find the diameter and the position of two circles, the buttons, whose dimensions change according to the wheel to be cut.
The pressure angle is very generally set at 20 į, so only the module (M) and the number of teeth (N) are necessary for the calculation, all the other dimensions are derived from it.

The angle is the half angular step 360 / (2xN).

Draw the primitive circle: dia = N x M; the outer circle: dia = (N + 2) x M; and the inner circle, with the endplay: dia = (N - 2.314) x M.

Draw the line of the pressure angle, which goes through "a", then a parallel which passes through the center of the wheel, "O", then the perpendicular which passes through "a"; its intersection with the second pressure line is the point "c", center of the first button, radius "ac".
The line "oc" is the radius of the base circle. The line "ac" must be tangent to the base circle in "c". It's over for the drawing.

The tool thus drawn will cut the metal between two teeth with the correct profile, starting with a blank turned to the outside dia and taking a total depth of 2.157 M for the number of teeth chosen; i.e. another tool is required for a different number of teeth.
For numeric values, some trigs is necessary ...
But doing the construction with a drawing software simplifies everything: the dimensions are taken directly from the drawing;

I simply cut the drawing and stick it on a HSS bar and grind the tool close to the layout...

I tested it and cut bronze wheels to the module 0.5M and 1M which mesh perfectly.
For Module 1 or tough material, a roughing pass with a saw helps.
 
Hope it is useful

Title: Re: 0.6 module involute cutters
Post by: Vixen on September 28, 2018, 10:07:36 PM
Hello Zephyrin

Thank you for this information. I will draw my required cutters using this information tomorrow. I can compare it with Jason's and Dan's information and also Ivan Law's information, they should all be nearly identical. I am becoming comfortable about making a single point cutter for the Delrin gears.

I have received help with these gears from all over the world,  truly international support from the MEM forum members.

It's also appropriate, as you live near Paris, The Jupiter model started life, being built by Dan, in Toucy near Auxerre , which is just a little way south of you. The Jupiter model has become an international engine project.

Thanks again

Mike
Title: Re: 0.6 module involute cutters
Post by: kvom on September 28, 2018, 11:03:44 PM
Here is the DXF file in R12 format if still of use.
Title: Re: 0.6 module involute cutters
Post by: pgp001 on September 28, 2018, 11:44:42 PM
Mike

If you get stuck let me know.

I have both 0.6M and 42DP hobs for my Mikron hobbing machine, if you machine the blanks and post them to me, I can cut the teeth on them for you.

Phil
Title: Re: 0.6 module involute cutters
Post by: jadge on September 29, 2018, 09:50:18 AM
The approach depends upon the equipment available. I'd model the involute profile in 3D CAD. Then, with a CNC mill available, one can either use the CAD model to mill a piece of HSS to the correct profile and use it as a flycutter, or go the whole hog and model a proper involute cutter that can be machined from gauge plate. For either method I'd create the model large size, say 1DP, and then make the last operation a uniform scaling, ie, divide by 42.333 or thereabouts.

Andrew
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 29, 2018, 11:22:58 AM
Thank you all, for your advise, offers of help and inspiration. The MEM forum is a very special place in which to hang out.

Thanks Phil for your generous offer to gearcut the blanks, it is good to know I have a backstop.

I am encouraged to have a go at making some single point cutters on my CNC mill. I have already modeled the cutter geometry. The cutters will be tiny. The 63t Delrin gear will have an outside diameter of 39mm, the cutter will be formed by two circular cuts, each of 12.93mm diameter. The mild steel 28t pinion will have an OD of 18mm and it's cutter will require two circular cuts of a mear 5.74mm. 

It's not quite watchmaking but smaller than clockmaking. I am looking forward to the challenge, safe in the knowledge that Phill can step in to help, should it go pearshaped.

Thanks again to all who 'pitched' in

Cheers  :cheers: :cheers:

Mike
Title: Re: 0.6 module involute cutters
Post by: pgp001 on September 29, 2018, 11:54:15 AM
Mike

I am curious as to why you need a 2.25:1 ratio, generally people are wanting a 2:1 ratio for cam drives etc.

Phil
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 29, 2018, 01:02:11 PM
Hello Phil,

Thanks for your kind offer to cut the gears.

The magneto drive for a big radial engine is full of mystery and magic. First off, a full size aircraft magneto usually has a four pole rotor and nine ignition leads. The drive to the magneto rotor must ensure there is one magnetic pole crossing for each spark. To achieve this, the magneto rotor turns at 1.125 time crankshaft speed to get a whole number of sparks per revolution.

The distributor part of the magneto, which feeds the nine spark plugs, is gear driven from the magneto rotor shaft and has the 2.25:1 reduction ratio. When you divide the 2.25: 1 gear reduction by the 1.125 speed up, you get the magic 2:1 ratio you were expecting i.e. all nine cylinder fire once for two crankshaft revolutions

Another problem with a magneto ignition system is, if you don't turn the engine over fast enough, you don't get any sparks to start the engine. The solution was often a additional hand cranked magneto in the cockpit, to give the pilot something else to do while he was trying to juggle the priming pump, the throttle and the ignition advance settings.

They certainly had a lot of mechanical design considerations to deal with back in those days. Today we would use a magnetic trigger off the flywheel and a box of fancy ECU electronics to do the same thing and more.

The cam ring drive is another mystery and another entirely separate story

Cheers

Mike  :old:
Title: Re: 0.6 module involute cutters
Post by: Jasonb on September 29, 2018, 01:10:23 PM
Mike, what formula did you use to calculate the cut diameters as the one for the 63T is quite a bit smaller than what I came up with from Ivan's book?
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 29, 2018, 01:31:29 PM
Jason,

I based my 0.6 module calcs of Zepherin's information, which is very similar to method as shown In Ivan laws book Fig 89. i.e. 20* pressure angle, tangent to the PCD etc.

I cannot explain why the 1 DP table corrected to 42.33 DP does not give the same result, but I did notice it. My calculations/ drawing  tie in with Dan Rowe's Gear Wheel Designer CAD drawing. I am happy my module calculations and CAD drawings are correct.

Cheers

Mike
Title: Re: 0.6 module involute cutters
Post by: Jasonb on September 29, 2018, 02:53:15 PM
It may be that the tabel in Law's book shows cutters to cover a range of teeth rather than calculating for the exact tooth count
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 29, 2018, 02:59:20 PM
Jason,

Agreed, the table does not specify the actual tooth count used, only a range and we know the circle diameters are dependant on tooth count.

The tooth face is only a very small part of the cutting (or button) circle. You have quite a bit out of latitude with the circle diameter before it makes any noticable (measurable) difference to the tooth profile.

Lots of useful information in his book though, I was interested in his ideas for single point cutters.

Mike
Title: Re: 0.6 module involute cutters
Post by: Stuart on September 29, 2018, 03:42:23 PM
I makes me very happy that as a community across the big ball can take the time and effort to help each other when a cry for help/advice it posted

Well done to all
Title: Re: 0.6 module involute cutters
Post by: Zephyrin on September 29, 2018, 03:50:24 PM
Hi Vixen
I'm sorry for the poor picture i've posted, how come it becomes so unreadable I dont know...
And yes, the geometry of method i described is exactly the "buttons" method but without buttons...

Buttons method come from the days where people made tools to do a tool to make a jig to hold a support for the part to be machined...
even if an epicycloide is replaced by a small circular arc the gears will be truly functional.

PS: I know perfectly were Toucy and Auxerre are; when much younger, I spend lot of my holidays in Auxerre, where my grandfather had a pharmacy business.
I used to pickup mushrooms in the fall in a forest close to Toucy, mainly cepes (Boletus edulis & Boletus rufus), good old days.
the world is a small village...
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 29, 2018, 03:59:07 PM
I makes me very happy that as a community across the big ball can take the time and effort to help each other when a cry for help/advice it posted

Well done to all

Plus 1 to that. I truly appreciate the help and support of everyone on the MEM forum :praise2: :praise2: :praise2:

We can all teach and learn from each other, we pull ourselves up with our own bootstraps.

Mike
Title: Re: 0.6 module involute cutters
Post by: Vixen on September 29, 2018, 04:06:29 PM
Hi Vixen
I'm sorry for the poor picture i've posted, how come it becomes so unreadable I dont know...

the world is a small village...

Hi Francois-Marie,

Your picture came out clear and sharp this end, no problems.

Great websites, lots of interesting engines

Mike