Author Topic: Eureka form relief tool  (Read 46858 times)

Offline raynerd

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Eureka form relief tool
« on: December 17, 2012, 05:46:59 PM »
A month or so ago now I put out an ad on homeworkshop for a eureka tool and managed to pick one up. Little more to be said about the purchase other than I was a little disappointed, the parts were poorly made and the device didn`t actually work!  :Doh:

Ahh well, a lot of time has been put into correcting this and also a lot of support from a fellow madmodder in helping me get this up and running. Its seems to be working OK now. Sadly there was no eccentricity built into the gear blank arbour and so it didn`t actually turn off centre! Also the ratchet clicks were incorrectly positioned and one was the incorrect size so it didn`t count the ratchet wheel properly. Finally the ratchet wheel had been hand cut and although actually I expect this would have been OK, I have used my divider and fly cut the wheel true and even. I`m pretty sure it is now running OK. The original plans allow the eureka to be held in the tailstock with an offset (to maintain concentricity) hole in the tailstock. I might be able to turn the end down and re-spot this but for now, you can see the end spot also turn eccentrically so it can`t be supported. I`m hoping that holding the Eureka in the three jaw will be good enough support it anyway.

The proof of this is in the successful cutting of a wheel cutting blank but I just wanted to post this up as I just think the concept is incredible! Whoever came up with this just thinks on a different level!



Offline mattinker

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Re: Eureka form relief tool
« Reply #1 on: December 18, 2012, 05:40:09 AM »
Chris,

Thanks for showing this amazing device.

I didn't understand how it worked without seeing a hob in it, a little web search and I found on HSMM a thread by Charles Lessig including a video of a hob being made.

 The thread,http://bbs.homeshopmachinist.net/threads/30041-Eureka-style-gear-hob-reliever-video

The video


Regards, Matthew

Offline raynerd

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Re: Eureka form relief tool
« Reply #2 on: December 18, 2012, 08:05:39 AM »
Hi Matt
Yes, I`ve seen Charles Lessig video - he has made some adaptations to the original plans to allow the relief of hobs. I`m hoping to just use this for single point cutters.

I hope it actually works when I give it a go in the next few days!
Chris

Rob.Wilson

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Re: Eureka form relief tool
« Reply #3 on: December 18, 2012, 04:22:10 PM »


 I just wanted to post this up as I just think the concept is incredible! Whoever came up with this just thinks on a different level!



Hi Chris

I think it was original designed (the type you have) by a Mr Blazer from the USA around 1900 .
 

It is a dam clever design , I built one too  :dremel:


Rob

Offline AdeV

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Re: Eureka form relief tool
« Reply #4 on: December 18, 2012, 04:48:36 PM »
Pardon my ignorance, and possibly stupidity; but what's the purpose of the tool; or, to put it another way, what, other than making a wiggly-shaped cut on a piece of metal, what does it do?
Cheers!
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Rob.Wilson

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Re: Eureka form relief tool
« Reply #5 on: December 18, 2012, 04:54:18 PM »
Well I am not telling you  :lol: :lol: :lol: :lol:


Rob

Online awemawson

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Re: Eureka form relief tool
« Reply #6 on: December 18, 2012, 05:32:54 PM »
Pardon my ignorance, and possibly stupidity; but what's the purpose of the tool; or, to put it another way, what, other than making a wiggly-shaped cut on a piece of metal, what does it do?

Let Google be your friend :)
Andrew Mawson
East Sussex

Offline raynerd

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Re: Eureka form relief tool
« Reply #7 on: December 18, 2012, 08:02:34 PM »
Rob - wow! I didn`t know it was shown in books prior to Ivan Laws book. Thanks for posting the book page. I see the top of the page says: Machine Shop Chat - is that the book title, I`d be interested in reading more?
Rob, do you find yours works OK and can you see any issue I may have running mine from the 3 jaw rather than turning between centres. Mine was made with NO eccentricity on the wheel cutting arbour so the damn wheel cutting end turned concentric with the lathe! To correct it, I`d either have to remake the majority of the centre eccentric parts or, the method i used, was to turn up an eccentric sleeve to slip over the end, held in the 3 jaw which puts the eccentric motion on the wheel holding section.


Ade - imagine a 12 tooth multitooth wheel cutter. This could be easily made using the button method or similar, jabbing the correct profile into the outside of a disk of steel and then cutting the gaps to create the teeth. The problem is that there is no relief on the teeth. This tool puts the relief on the teeth. You have to set it correctly so that the eccentric motion is cutting the "back" side of the teeth and forming the relief. I.e you cut away the yellow on the image below:


 

Online awemawson

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Re: Eureka form relief tool
« Reply #8 on: December 19, 2012, 03:29:27 AM »
Mine was made with NO eccentricity on the wheel cutting arbour so the damn wheel cutting end turned concentric with the lathe! To correct it, I`d either have to remake the majority of the centre eccentric parts or, the method i used, was to turn up an eccentric sleeve to slip over the end, held in the 3 jaw which puts the eccentric motion on the wheel holding section.



Is it not supposed to be mounted in a four jaw chuck, so that the 'throw' of the eccentric is adjustable not fixed ?
Andrew Mawson
East Sussex

Offline John Stevenson

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Re: Eureka form relief tool
« Reply #9 on: December 19, 2012, 04:00:32 AM »
No the body which holds the eccentric runs true so 3 jaw, the eccentric part has an off set center in the end so although the eccentric runs eccentrically the center runs true so it can be supported.

Intersting thing with these is no matter which way the tool runs the cutter being relieved always runs forward
John Stevenson

Offline raynerd

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Re: Eureka form relief tool
« Reply #10 on: December 19, 2012, 05:04:19 AM »

Intersting thing with these is no matter which way the tool runs the cutter being relieved always runs forward

Yes, noticed that, totally amazing!



Offline AdeV

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Re: Eureka form relief tool
« Reply #11 on: December 19, 2012, 05:38:00 AM »
Thanks Chris, that picture explains perfectly what a dozen websites failed to convey  :thumbup:
Cheers!
Ade.
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Offline hopefuldave

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Re: Eureka form relief tool
« Reply #12 on: December 19, 2012, 12:06:04 PM »
That's a magical device alright... But for the truly pedantic...

 It can only relieve straight-fluted cutters! For spiral (OK, helical) flutes you're into the weird world of geared relieving attachments which work by moving the tool rather than the workpiece - for them as is unaware of such....

 Usually the spindle speed's reduced by an add-on gearbox sat on the ways in front of the headstock, driven by the spindle and with a matching spindle nose on the output side (often 6 or 8 to 1 reduction, call it 1/n);

 A geartrain (with pick-off gears) separate from the QCGB / change-gears rotates (via universal joints and a telescopic shaft) a cam which moves the form-cutting tool into the workpiece, Firm Spring Pressure returns the tool to the rest position;

The topslide (compound) is attached to a slide which is under the control of the cam.

 By varying the gearing driving the cam it's possible to get straight relief of any (practical) number of flutes by choosing integer ratios of cam to (output) spindle speed, if the ratios are non-integer then each relief starts at a slightly (or even very) different position around the workpiece, resulting in a helical relief - and a lot of calculations!

 As the spindle's rotating the workpiece at constant speed it's possible to use the lathe's QCGB to set the pitch (and handedness) of the cutter teeth for making taps etc. (but set at n x desired tpi pitch - the 1/n spindle reduction, remember! For n = 8 cutting a 16 tpi tap would need a setting of 128 tpi on the QCGB - this may explain why toolroom lathes often go to what appear to be daftly-fine thread pitches?).
 The Eureka etc. instead use a follower as in the Lessig video to establish the thread pitch, which works just fine but needs a different follower and thread prototype for every pitch... Some of the finer instrument lathes came with thread followers and sets of prototype threads as very pricey accessories!

 The lathes best suited for these attachments have "double cross-slides" that put the lower slide under control of the cam (or taper attachment when not relieving) and allow the upper slide to be used for in-feed; better yet some of the official manufacturer's attachments have a third slide between cross-slide and topslide so they can cut helically-relieved, tapered cutters and taps! Too clever for me... I've not used one, but have long ago seen 'em in action a few times, attached to older Hendey, Pratt & Whitney and Holbrook toolroom lathes making special taps etc.

 I suspect it'd be possible to home-brew a relieving attachment (assuming you have access to the quadrant gears to pick up the drive or can pick up from the spindle-speed reducing box), but a lot of work for someone much braver than me! A lathe with a taper attachment could be fitted with a cam/ follower assembly in place of the taper guide, perhaps? Of course, in these days of (relatively) inexpensive CNC there's probably an easy way to do it in software :) Sir John would probably know.


Dave H. (the other one, rambling again)
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Offline rotorhead

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Re: Eureka form relief tool
« Reply #13 on: December 19, 2012, 01:26:13 PM »
Hello Lads,

Might I be so bold, as to ask if there is a current set of drawings, or even Ivan Laws publication available among'st the fora, for this contraption.

Chris
Chris
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Rob.Wilson

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Re: Eureka form relief tool
« Reply #14 on: December 19, 2012, 01:55:52 PM »
Rob - wow! I didn`t know it was shown in books prior to Ivan Laws book. Thanks for posting the book page. I see the top of the page says: Machine Shop Chat - is that the book title, I`d be interested in reading more?
Rob, do you find yours works OK and can you see any issue I may have running mine from the 3 jaw rather than turning between centres. Mine was made with NO eccentricity on the wheel cutting arbour so the damn wheel cutting end turned concentric with the lathe! To correct it, I`d either have to remake the majority of the centre eccentric parts or, the method i used, was to turn up an eccentric sleeve to slip over the end, held in the 3 jaw which puts the eccentric motion on the wheel holding section.




Hi Chris


Yes there a few versions of the reliving attachment going back yonks , The book is "Shop Kinks by Robert Grimshaw  1911"  I can scan the pages if you wish ,there are only two covering this, or you may fined the book on line or some company do print on demand (mine is an original copy)  .

Yes my relieving attachment  works well , I did case harden some of the components and add oiling holes .

Here it is made about 20 odd years ago .


Only made about 10 cutters on it ,here are a couple .


IF I were to make another I would   make it double the size  :dremel:


Holding in the three jaw would be fine ,I personally would remake the faulty part Chris  :poke:


Rob


Rob.Wilson

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Re: Eureka form relief tool
« Reply #15 on: December 19, 2012, 02:53:37 PM »
Hello Lads,

Might I be so bold, as to ask if there is a current set of drawings, or even Ivan Laws publication available among'st the fora, for this contraption.

Chris

Here you go http://www.amazon.co.uk/Gears-Gear-Cutting-Workshop-Practice/dp/0852429118


Rob

Offline philf

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Re: Eureka form relief tool
« Reply #16 on: December 19, 2012, 04:11:22 PM »
Rob, Chris,

The Stephen M Balzer attachment is a different beast to the Eureka. It uses gears. It was patented in 1895. You can view the patent application here:

https://patentimages.storage.googleapis.com/pdfs/ec8d3eb4c5ebb85c2ce3/US535127.pdf

In 1906 Charles G Taylor patented another relieving attachment which looks a little more like the Eureka:

https://patentimages.storage.googleapis.com/08/e4/92/3588edcf0129bc/US817885.pdf

I have a book dated 1916 with another variation looking even more like the Eureka but it allows cutters with 9, 12, 18 & 36 teeth to be backed off.



I've attached a pdf of the article including an explanation. It's much easier to understand if you've got one mounted on the lathe in front of you as Craynerd knows.

Rob - what material did you use for your cutters? I'm thinking of using O1 tool steel. (By the way Rob - I've just remembered that I promised you a stereo microscope!)

Phil.
« Last Edit: January 12, 2023, 06:00:19 PM by philf »
Phil Fern
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Offline rotorhead

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Re: Eureka form relief tool
« Reply #17 on: December 19, 2012, 04:26:46 PM »
Hi Rob,

That's great stuff, went straight there and it should be here Friday, with '1 day click'

I'll save those very nice pics of yours too, and later I'll look for that other book you mentioned.

Thanks for that Rob, a scanned page or two would be appreciated, as the more cross referencing of the same principle would help towards stress relieving my brain cells.

Whilst typing this missive I received another posting notice, thanks go to Phil as well.

Chris
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Rob.Wilson

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Re: Eureka form relief tool
« Reply #18 on: December 19, 2012, 04:29:14 PM »
Hi Phil


Nice patent finds  :thumbup:

 If you have a look at the photo I posted in shows a ratchet and pawl and re reading the text it dose not mention gears on this device .


I used gauge plate to make my cutters .


Rob

Rob.Wilson

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Re: Eureka form relief tool
« Reply #19 on: December 19, 2012, 04:32:02 PM »
No worries Chris  (rotorhead)


I take it your planning on making one ?


Rob

Rob.Wilson

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Re: Eureka form relief tool
« Reply #20 on: December 19, 2012, 04:49:55 PM »
Here you go lads , scan from book attached .


Rob

Offline philf

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Re: Eureka form relief tool
« Reply #21 on: December 19, 2012, 05:14:13 PM »
Here you go lads , scan from book attached .

Rob

Rob,

That description is more comprehensive than the one in my book but seems to describe exactly the same tool.

Phil.
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Offline Simon0362

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Re: Eureka form relief tool
« Reply #22 on: December 19, 2012, 05:34:42 PM »
There was a simplified version published in Model Engineer (according to my hunt, 1987, issue 3794, 3804 and 1988 issue 3820).
I extracted the 2 issues a couple of years ago with the intention of making it - and then moved house which delayed all construction projects and has left the 2 issues 'somewhere'...
Having a CNC mill, it looked like it was crying to be made using that - perhaps in combination with water jet cut blanks - any takers?

Simon

Offline John Stevenson

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Re: Eureka form relief tool
« Reply #23 on: December 19, 2012, 05:40:10 PM »
Made one a few years ago, in fact got paid to make it as we needed it to make some special cutters.
Scaled everything up X 2 so it used 1" bore cutters, made out of bright mild steel plate but everything was Cyanide hardened professionally.

Made loads of cutters but ironically never made a gear cuter on it.
John Stevenson

Offline BillTodd

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Re: Eureka form relief tool
« Reply #24 on: December 19, 2012, 06:06:18 PM »
Presumably, the relieving tool has to have the same profile (or at least a mirrored/ double sided profile - IYSWIM) as the originating threading/forming tool - does it?


Bill
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Offline PekkaNF

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Re: Eureka form relief tool
« Reply #25 on: December 20, 2012, 02:30:58 AM »
Presumably, the relieving tool has to have the same profile (or at least a mirrored/ double sided profile - IYSWIM) as the originating threading/forming tool - does it?

Bill

Is this part of an aswer to your question?:
http://mikesworkshop.weebly.com/designing-gear-cutters.html
Rather interestingly:
http://metalwebnews.com/howto/gear/gear1.html
and:
http://mikesworkshop.weebly.com/making-gear-cutters.html

Pekka

Offline rotorhead

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Re: Eureka form relief tool
« Reply #26 on: December 20, 2012, 03:52:13 AM »
reynard,

I owe you an apology for not realising I'm not the only Chris on here.

In my enthusiasm at finding reference to the Eureka tool, I blundered on, thinking I was initially being replied to, until Rob qualified the Chris with (rotorhead).

So apologies to all actually.

Rob, thanks for the scan, and yes it is my intention when time permits, to make one.
My thinking already, is with the suggestions on here, that I'll go the double size route.

Chris(the other one)

P.S. How does one get the smilies to show where you want them?
« Last Edit: December 20, 2012, 05:23:56 AM by rotorhead »
Chris
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Offline SLM

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Re: Eureka form relief tool
« Reply #27 on: December 20, 2012, 09:24:46 AM »


Chris(the other one)

P.S. How does one get the smilies to show where you want them?

Either directly  add the code where you want the smilies or click the one you want with the mouse keeping your blinking cursor where you want it. Hopefully that makes sense.

Offline BillTodd

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Re: Eureka form relief tool
« Reply #28 on: December 21, 2012, 07:24:53 AM »
Thanks Pekka :)


Presumably, the relieving tool has to have the same profile (or at least a mirrored/ double sided profile - IYSWIM) as the originating threading/forming tool - does it?

Bill

Is this part of an aswer to your question?:
http://mikesworkshop.weebly.com/designing-gear-cutters.html
Rather interestingly:
http://metalwebnews.com/howto/gear/gear1.html
and:
http://mikesworkshop.weebly.com/making-gear-cutters.html

Pekka
Bill

Offline raynerd

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Re: Eureka form relief tool
« Reply #29 on: December 21, 2012, 03:30:15 PM »
Hi guys, interesting conversation this has started. I`ve just become a dad again so I`ve been away for the last few days! I`ve enjoyed reading all the links and attachements. Thanks.

Rob - I could remake the part but it is so poorly made I`d be as well remaking the entire thing!

Chris


Offline raynerd

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Re: Eureka form relief tool
« Reply #30 on: December 21, 2012, 03:31:02 PM »
Rob - one more thing. On the cutters you made, how do you get such crisp even stamping ?  Are they just standard letter punches?

Offline John Stevenson

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Re: Eureka form relief tool
« Reply #31 on: December 21, 2012, 03:33:50 PM »
Rob - one more thing. On the cutters you made, how do you get such crisp even stamping ?  Are they just standard letter punches?

Photoshop...................
John Stevenson

Offline raynerd

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Re: Eureka form relief tool
« Reply #32 on: December 21, 2012, 03:36:54 PM »
I couldnt get them like that photoshop!

Think I need to invest in some new ones. All mine are second hand sets.

Rob.Wilson

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Re: Eureka form relief tool
« Reply #33 on: December 21, 2012, 03:52:58 PM »
First off congratulation Chris  :clap: :clap: :clap: :clap: :clap: nice one :thumbup:


Is it that bad   :palm: , sure it just dose not just need the part that you mount the cutter on re-made .

Yes just stamped with normal hand stamps ,,,, here a few photos to show how , nowt flash just made a small stamping guide.




 :lol: :lol: Photoshop my secret is out  :palm:

Rob

Offline PekkaNF

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Re: Eureka form relief tool
« Reply #34 on: December 22, 2012, 03:43:14 AM »
..... I`ve just become a dad again so I`ve been away for the last few days! .....
Rob - I could remake the part but it is so poorly made I`d be as well remaking the entire thing!
Chris
Congratulations Chris!

I think that a lot can be learned from nonworking scale size model. Least that what I usually end up producing first almost every time. The bright side is that metal objects are faster to remake than babies - they have certain set up times. :)

Pekka

Offline rotorhead

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Re: Eureka form relief tool
« Reply #35 on: December 22, 2012, 05:08:15 AM »
Chris,

Congratulations, well done lad.

Pekka, you'll get the hang of it, if you keep trying mate.

Chris(the other one)
Chris
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Offline raynerd

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Re: Eureka form relief tool
« Reply #36 on: December 22, 2012, 08:58:06 AM »
Thanks guys!

Rob, that guide is bloody genious!!   

Currently sat with my son over one shoulder, my daughter pulling my toes and Peppa Pig on the TV - time free in the workshop seems a time off!
 
Chris

Offline John Stevenson

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Re: Eureka form relief tool
« Reply #37 on: December 22, 2012, 09:20:41 AM »
Thanks guys!



Currently sat with my son over one shoulder, my daughter pulling my toes and Peppa Pig on the TV - time free in the workshop seems a time off!
 
Chris

Buy a treadmill.
John Stevenson

Offline raynerd

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Re: Eureka form relief tool
« Reply #38 on: December 30, 2012, 05:05:18 PM »
Got a couple of hours in the workshop while my wife`s friend came around.

Eureka worked well and I think I`ve produced a useable cutter however the problem I had was that for this 0.6 mod cycloidal cutter profile I needed a 0.92mm radius "button" profile tool. As suggested in the past, a suitably ground drill bit works so I picked a 2mm drill bit and ground the profile on the end. However, It just isn`t rigid enough and consequently there is flex in the cut. Multiple cuts works but there are problems. I just can`t image grinding a round 0.92mm profile radius onto a larger more rigid bit of tool steel.

Suggestions welcome. However, it has worked!






The picture below shows the steel blank mounted on a mandrel with 12 x 4mm holes drilled as near to the edge as possible. The wheel is then turned down in the lathe to expose the holes. These holes become the back relief and gap between teeth.






Finally the finished cutter, with relief!






Offline philf

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Re: Eureka form relief tool
« Reply #39 on: January 18, 2013, 04:18:32 PM »
Prompted by Chris's efforts to produce cutters for clock wheels and pinions I thought I'd have a go myself.

I bought a Eureka relieving attachment via Homeworkshop.org some time ago and it's sat in a box ever since. It's much better finished than Chris's but still I had to make a few improvements. One problem was that the arbor ran out by 0.2mm. The guy who made it decided on 3/4" bore cutters rather than 1/2". I set up the arbor in the 4 jaw and got the bore running true and then skimmed it down to 16mm. (The clamping thread was 5/8" so didn't need recutting.) The arbor was bushed with, I think, brass and the bush was a very very loose fit so I remade it a press fit in the arbor and a nice running fit on the eccentric shaft.



Many years ago at work we used KE672 oil hardening low distortion tool steel and I managed to get an old colleague to find me 12" of 1.5" diameter. I sawed this into slices and faced them up in the lathe. So I could face the thin disks parallel I made a support which fitted in the bore of my 3 jaw and was just under 3mm shorter than the chuck jaws. I faced this holding it in place with a running centre with the chuck jaws removed. The slots are marked with the jaw numbers so it always goes back in the same orientation so should produce perfectly? parallel parts.



I made 20 or so blanks which were drilled and bored to 16mm. (No 16mm reamer!)

The button method of machining the profile on the cutter for involute gears isn't so straightforward for cycloidal cutters as the flanks of the cutter have to be radial with a radius at the root. I also chose to make the cutters with a radius at the tips so the finished clock teeth will have round bottoms. You can't achieve that with a button tool. (Antique clocks always had square bottoms but modern practice is to have round bottom teeth which are stronger.) As Chris found the button method would require buttons of less than 1mm diameter which wouldn't be stiff enough unless they were tapered. Having a CNC miller, I thought that it would be possible to machine a form tool with the tooth form to put the profile on the cutter. This form tool would also need a relief angle so that it didn't rub on the cutter. I chose 5 degrees as that's what seemed to be specified for the button method. To get the relief I angled the form tool blank at 5 degrees to horizontal. This would give a constant profile which would allow sharpening without losing the profile. I drew the form tool in Autocad and then generated the GCode in Cut2d. With a 0.8mm end mill at 10,000 rpm I cut the form into 6mm gauge plate which was then hardened (in old cooking oil) and tempered (in the deep fat fryer). The top surface of the tool looks dog rough but this was taken through a microscope and is the gauge plate finish before heat treatment and polishing. The radiuses on the tool are just over 0.4mm.





To remove the bulk of the material from the cutters I chamfered either side of the blank which would also help centre the form tool on the blank. The method of slotting the blank given in Ivan Law's book is to drill 12 holes and then saw into the holes. This may be OK for one or two cutters but I thought the CNC could do this job with ease.



The first attempts at forming the teeth on the blanks with the Eureka were very disappointing. I seemed to be getting nice little chips for a while but then the cutting seemed to slow up. I thought that perhaps the form tool was dulling too quickly but, on examination, it looked fine. After a few abortive attempts I decided that 5 degrees clearance on the form tool wasn't enough. The Eureka puts the relief on the cutter and I guess that this was also about 5 degrees. So, once the tooth started to form, it very soon started to rub on the cutter. I remade the form tool with 7 degree clearance and had another go. This worked OK for 8 and 12 tooth pinion cutters but when I tried to profile the wheel cutter (which has a much deeper form) I again had problems and had to make yet another form tool with 8 degree clearance.

Here are a few photos of the finished hardened cutters (just awaiting the deep fat fryer tempering and then sharpening).







I've marked the cutters with an Actograp engraver - not as neat as Rob's method of stamping but much quicker and I don't have any letter stamps. Perhaps I'll engrave them on the CNC if I make any more.

Phil.
« Last Edit: July 13, 2017, 02:34:46 PM by philf »
Phil Fern
Location: Marple, Cheshire

Rob.Wilson

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Re: Eureka form relief tool
« Reply #40 on: January 18, 2013, 04:41:52 PM »
 :thumbup: Very nicely done  Phil


Using the CNC would have speeded the process up a fair bit  :med:


Rob

Offline raynerd

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Eureka form relief tool
« Reply #41 on: January 23, 2013, 04:32:23 PM »
Ahhhhh, I missed this Phil.

These look amazing Phil and you know that I'll be following closely. The CNC profile tool seems the way to go.

Also, I think based on your quality eureka tool for half the price I got mind for, I'm going to remake mine. I paid £50 and it looks like a dogs dinner and fit for the crap bin. It does a job but despite best efforts, it isn't turning true.

Ok, a clock to a least start but I'll be back t this thread.

Phil, please update us how it cuts.

Chris

Offline philf

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Re: Eureka form relief tool
« Reply #42 on: January 24, 2013, 11:34:33 AM »
Ahhhhh, I missed this Phil.

These look amazing Phil and you know that I'll be following closely. The CNC profile tool seems the way to go.

Phil, please update us how it cuts.

Chris

Chris,

I managed an hour in the workshop today and tried a 12 tooth pinion. I did it on the Aciera with the dividing head as my CNC won't run at 60 rpm.

This is the result:



I'm pretty pleased with it - it looks better in real life than in the picture. (I took the picture with a USB microscope as my compact digital has died. It could be better focussed.)

It's 8.09mm OD and was cut in one pass with a 1.49mm depth of cut with plenty of cutting oil brushed on.

Phil.
« Last Edit: July 13, 2017, 02:33:01 PM by philf »
Phil Fern
Location: Marple, Cheshire

Rob.Wilson

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Re: Eureka form relief tool
« Reply #43 on: January 24, 2013, 11:38:56 AM »
I would be well pleased with that too Phil  :thumbup:

Well done  :clap: :clap:

Rob

Offline Simon0362

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Re: Eureka form relief tool
« Reply #44 on: January 25, 2013, 02:55:07 PM »
Very impressive....
Do I understand that you were running the cutter at 60rpm? What feedrate did you use - if you can tell?

Regards,
Simon

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Re: Eureka form relief tool
« Reply #45 on: January 25, 2013, 03:26:30 PM »
Very impressive....
Do I understand that you were running the cutter at 60rpm? What feedrate did you use - if you can tell?

Regards,
Simon

Hi Simon,

Yes - I used about 60 rpm. I can't tell what the feed rate was as it was done by hand. My guess is only about 10mm/minute. I would have liked to use my CNC so I could have used a known feed rate and my 4th axis but that has a minimum speed of about 166 rpm which is a bit too fast for a carbon steel cutter cutting a silver steel pinion.

I've finshed the turning of the pinion now and have hardened and tempered it. I just need to finish polishing it when I get a new tube of Solvol Autosol tomorrow - I have a nearly full tube somewhere.................

Cheers.

Phil.
Phil Fern
Location: Marple, Cheshire

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Re: Eureka form relief tool
« Reply #46 on: January 25, 2013, 09:05:44 PM »
Top trumped me there! I was chuffed with my wheel but that pinion is FAB!!!

Offline Boo

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Re: Eureka form relief tool
« Reply #47 on: January 11, 2023, 08:23:53 AM »
Apologies for the thread resusitation but I thought that it would be better to have my question here rather than start a new thread and have the group end up covering the same ground again.

I was thinking of building a Eureka tool to assist in making gear cutters for small gears for model engines but using a 16mm bore diameter to suite my existing mandrels.  I wondered what the group thinks about thickness of the Ratchet Plate and the Anchor plate ?  Scaling from 12.7mm to 16mm gives something like 10mm and 8mm respectively and I can get gauge plate in both these sizes.  Is gauge plate worth using does the group think ?  I can see that the pawls would also benefit from being made from gauge plate but would any other parts benefit ?

On the subject of gauge plate, I've never used it and don't know what it is like to work with in practice in the annealed state - can anyone tell me how it is to hacksaw, file and machine in general ?  I assume there is no prospect of using a jigsaw on it in these thicknesses and retain any degree of sanity ?

Many thanks,

Boo

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Re: Eureka form relief tool
« Reply #48 on: January 11, 2023, 09:58:35 AM »
Gauge plate (silver steel) in the anealed state is quite nice to work with hand tools, but hardens nicely.

As for the Eureka and scaling it up, I've only used one years ago, and that was made by someone else but I don't suppose dimensions of plate thickness are too critical after all it's not intended to make massive cuts.
Andrew Mawson
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Offline Boo

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Re: Eureka form relief tool
« Reply #49 on: January 11, 2023, 03:26:46 PM »
Gauge plate (silver steel) in the anealed state is quite nice to work with hand tools, but hardens nicely...
Thanks, I suppose an alternative would be to chop it up with an angle grinder, but would there be issues with hard spots doing that do you think ?

Boo

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Re: Eureka form relief tool
« Reply #50 on: January 11, 2023, 04:26:06 PM »
Hi Boo,

I have a Eureka (like Andrew I didn't make it).

Mine looks to be the same as the one published in Ivan Law's "Gears and Gear Cutting" but was made for 19mm (or maybe 3/4") bore cutters and I modified it to take 16mm. I don't think you need to scale everything.

I'm not keen on machining gauge plate - it's certainly a lot more difficult than mild steel. There are only a few bits listed that require hardening and the book suggests case hardened mild steel. Hardening and tempering gauge plate is (to me anyway) easier than case hardening.

As an aside we used to use KE672 steel for making tools at work. KE672 and Gauge Plate were of similar ingredients but our toolroom 'much' preferred KE672 for its machining properties.

The pawl on mine is easily fileable so definitely not case hardened.

Phil.
« Last Edit: January 14, 2023, 05:15:10 AM by philf »
Phil Fern
Location: Marple, Cheshire

Offline philf

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Re: Eureka form relief tool
« Reply #51 on: January 13, 2023, 03:49:16 PM »
I was thinking of building a Eureka tool to assist in making gear cutters for small gears for model engines but using a 16mm bore diameter to suite my existing mandrels.  I wondered what the group thinks about thickness of the Ratchet Plate and the Anchor plate ?  Scaling from 12.7mm to 16mm gives something like 10mm and 8mm respectively .........

I've just looked at the drawings in Ivan Law's book and my Eureka. Don't bother scaling anything just make the ratchet sleeve with a 16mm diameter rather than 1/2". I've shown an M16 x 1 thread because it is a standard tap size.



Phil.
Phil Fern
Location: Marple, Cheshire