Author Topic: Meek bigbore dog clutch  (Read 24940 times)

Offline Bjorn_B

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Meek bigbore dog clutch
« on: March 30, 2016, 08:38:48 PM »
Been at this for a while, this will be done before the Quick-step I guess (still on hold)

The body is a really complex shape, I had to draw it up in a 3D format to get my head round to it. I'm not saying that Grahams plans ar by any means bad (they are excelent) but third degree projection does catch me out sometimes, specially with complex items.

Lots of swarf was made doing this! and there seems to be a need for some more as the body is interfering a bit in the back end...
 20160329_205411 by Bjorn Bursell, on Flickr

Input gear blanks from tufnol, lots of fun and games to machine theese, I'm all covered in dust!.
20160330_192536 by Bjorn Bursell, on Flickr

Shafts from EN24t, no toolpost grinding used, a method I learnt from the GTBA forum (I guess from Peter Chaffe?) when making turbine shafts was a bit 320 grit wet and dry backed by a flat piece of steel and a bit of cutting oil at high spindle speed was used instead. quite fine tolerances on shafts can be done this way (well within 0,01mm with a bit of care)
20160330_201312 by Bjorn Bursell, on Flickr

More fun and games to follow as the next thing up is cutting the tufnol gear teeth and perhaps some further massaging of the main body to make it fit the lathe..

Offline pgp001

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Re: Meek bigbore dog clutch
« Reply #1 on: March 30, 2016, 10:33:20 PM »
It is definitely worth all the effort, the Meek dog clutch has got to be one of the most useful bits of tooling I have ever made for my own Super 7.

Phil


Offline steamer

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Re: Meek bigbore dog clutch
« Reply #2 on: March 31, 2016, 04:05:29 PM »
Sweet!   I have the SB design and I'm going to do it!    Waiting for those 36 hour days to start up...... :help: :-[
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Offline Graham Meek

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Re: Meek bigbore dog clutch
« Reply #3 on: March 31, 2016, 04:23:50 PM »
Hi Bjorn,

Thanks for sharing the build with us, you are making good progress. The very first Super 7 screwcutting clutches back in the 1980's were originally sketched out free hand in Isometric, just to make sure I had got it right. There was no AutoCAD etc, back then, well not for the masses anyway.

My best regards
Gray,

Offline Bjorn_B

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Re: Meek bigbore dog clutch
« Reply #4 on: March 31, 2016, 05:22:12 PM »
Oh dear, I better get this done proper now that master Graham is peeking over the shoulder.. Thanks for all your input!

Small steps toward gearcutters done at the moment, not much interesting to see as I'm waiting for loctite to set in a button tool. Will make bespoke cutters on the Eureka for this.

Offline Bluechip

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Re: Meek bigbore dog clutch
« Reply #5 on: March 31, 2016, 09:09:03 PM »
Bjorn

Not too sure about your Tufnol. It looks to me from the colour of the pics. that it may be 'Kite' brand, which is generally used for electrical components rather than gears. It is SRBP.

The usual Tufnol for gears is SRBF.

http://www.tufnol.com/materials-full/paper-laminates/kit-brand.aspx

http://www.tufnol.co.uk/technical/tufnol-gears.aspx

Just a thought ...  :ThumbsUp:

Dave

Offline Bjorn_B

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Re: Meek bigbore dog clutch
« Reply #6 on: March 31, 2016, 09:23:20 PM »
Thanks Dave, Will cut a gear from it and test it a bit. Did chose tufnol for theese gears to make this as quiet as possible, the gears will be in mesh all the time with this setup as this in some way replaces the tumbler reverse and gears

Offline pgp001

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Re: Meek bigbore dog clutch
« Reply #7 on: March 31, 2016, 10:18:06 PM »
Another reason why Myford chose Tufnol for the tumbler gears is that it will break teeth easily if you get a crash situation. Dont ask how I know this to be true   :-[

When I made my Tufnol gears for the Meek clutch, I used sheet form as opposed to bar form material, as I understand it the material is laminated in a different direction and in bar form will produce weak gear teeth. I also chose to run the Tufnol idler gears on pairs of sealed ball races.





Phil
« Last Edit: March 31, 2016, 11:04:35 PM by pgp001 »

Offline Bjorn_B

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Re: Meek bigbore dog clutch
« Reply #8 on: April 02, 2016, 06:56:38 PM »
That looks very nice Phil, not shure I can get up to that standard, but anyways..

As I did a major misstake on the button tool (to embarrasing to mention really :embarassed:) I went for the flycutter route for cutting the tufnol gears, flycutter itself is similar to what Graham mentions in his book, uses a piece of 6mm square gauge plate material.

20160402_125517 by Bjorn Bursell, on Flickr

Backing piece of aluminium to stop the tufnol from delaminating (sheet material, not strong in this direction) Mill and me and the rest of the workshop is now covered in dust...

Have allso made embryo gear blanks for the dog gears out of EN16t, those will be more of a challange to cut perhaps..

Cheers!  :cheers:


Offline Bjorn_B

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Re: Meek bigbore dog clutch
« Reply #9 on: April 13, 2016, 09:17:47 PM »
Edited the pictures to a more reasonable size, got a new computer here with the horrible microsoft edge browser as default..

Gear blanks for the two dog gears are made from EN16t with bronze bushings, first time I have tried Colphos 90, what a lovely material to machine!

[url20160403_094603 by Bjorn Bursell, on Flickr

one of the dog gear blanks, no teeth are cut yet, tried a bit with my home made flycutter style gear cutting bit but this steel wins over home hardened gauge plate or silver steel all the time so I will go for a commercial HSS M1,25 gear cutter instead. There is only a gnats hair in difference between the tooth profile of this this and a 20DP, 20pa gear.

20160403_112331 by Bjorn Bursell, on Flickr

This is where it all happens, the dog clutch output driver, also made from EN16t, lots of material is machined away on this, so it is now pretty light. Keyway was cut while in the myford with the hand slotting attachment. Radial grooves either side for the dog teeth made the mill with the dividing head used in a rotary table fashion.

20160412_205056 by Bjorn Bursell, on Flickr

20160412_205408 by Bjorn Bursell, on Flickr
« Last Edit: April 14, 2016, 04:23:23 PM by Bjorn_B »

Offline zeeprogrammer

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Re: Meek bigbore dog clutch
« Reply #10 on: April 13, 2016, 10:24:49 PM »
I hadn't heard of Tufnol before. Looked it up to see that it's some kind of laminated plastic.

But I'm wondering about a couple of other terms...

'dog gears' and 'dog clutch'

I know gear and clutch. What does it mean to qualigy with 'dog'?

Thanks
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Offline Stuart

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Re: Meek bigbore dog clutch
« Reply #11 on: April 14, 2016, 07:27:42 AM »
Bjorn

I made my gears from Oilon ( oil loaded delrin)

I used the same doge with the gear cutter 😀

When Gray did this version it was with the dims supplied by me from my conny

You will find it a wee bit tight to get mounted it's the end float (spindle ) coller that it the trouble


Zee dog clutch is the term for a clutch that will engage in the same place hence it will index , that's why they work for this application the grove allows the engagement but drive pickup is in the same place

They are fitted with a trip arm to open the clutch at a preset travel , very like a Hardinge lathe

Bjorn
Have fun but do read the book carefully with regard as to the indent ball for the selector 😬😬😬😬 Gray lost his down the hole but I did not 😀

Stuart
My aim is for a accurate part with a good finish

Online Jo

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Re: Meek bigbore dog clutch
« Reply #12 on: April 14, 2016, 07:50:09 AM »
I made my gears from Oilon ( oil loaded delrin)

 :thinking: I was given a load of that stuff, not sure what to use it for. Its a sort of greeny not really plastic sort of stuff  :noidea:

Jo
« Last Edit: April 14, 2016, 10:02:36 AM by Jo »
Enjoyment is more important than achievement.

Offline Stuart

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Re: Meek bigbore dog clutch
« Reply #13 on: April 14, 2016, 08:15:34 AM »
Jo

It's used as a bearing material just like oilite but I believe in the food industry

http://www.directplastics.co.uk/oilon-rod


I used it for two reasons it is self lubicating and it's cheaper than the correct type of Tufnol

You do need the flat plate that has the fabric going in the correct plaine , the rod stuff is no good and will crack if used in this application .

To buy plate Tufnol thick enough is well not good

The Oilon is wearing ok and still gives a bit of a safety to the gear train

Gray used brass or bronze in the S7 variant


Stuart
My aim is for a accurate part with a good finish

Offline pgp001

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Re: Meek bigbore dog clutch
« Reply #14 on: April 14, 2016, 08:28:16 AM »
I would not use metal gears in those positions unless you wear ear defenders all the time !!

Phil

 

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