# Gear cutting in a lathe.



## Retired (13 Jan 2021)

Hi,

I adopted restoring vintage valve radios as a winter hobby when I retired in 2000 knowing nothing about them; I wanted to leave my comfort zone and try something new. I then spent the next ten years becoming deeply involved in this new hobby to the point of having articles published in the BVWS Bulletin (British vintage wireless society). I was self taught with help from radio forum members but I also learned transformer winding; wood veneering and French polishing.

In 2009 I was honoured by the society gaining top award for best restoration 2009 which I found truly humbling considering I had started the hobby from scratch just to enjoy during winters. The restoration wasn't a vintage radio but an AVO Wave Winder these winders used to wind tuning coils and they are rather complicated machines. Whilst buying enameled copper winding wire I spotted this very rough looking winder and as I'm a mechanical engineer thought what a lovely project it would make; even in its rough state it wasn't cheap but I soon had it on the bench. The winder proved to be virtually scrap it was seized solid with rust and parts were missing; just like the kind of challenge I like.

It's a long story but I fully rebuilt the winder and made the parts which were missing; the only problem was it didn't have a single gear and the manual stated it should have about 45 change gears in the full set? What a dilemma; I'd never made a gear and didn't even know the diameters or number of teeth also what was the tooth profile? I'm a member of a vintage wireless forum in fact the first ever forum I joined; the restoration was being watched and I posted on the forum for gear information. a forum member stepped up kindly sending me pictures of his own working winder so at least I now had a basic idea.

At the time I'd bought a very old rare Myford engineering lathe which was described as in excellent condition; having collected the lathe and it now on my bench running it didn't take long to find the headstock main bearing housing was broken rendering the lathe scrap; oh what fun I do have. I clamped the bearing housing securely and proceeded to experiment cutting gears firstly from Whale Tufnol. The biggest problem was the gear diameters and the tooth profile; I did many hours researching and "Involute" gears looked the correct type but how to make these? I've been using lathes for over half a century but never for a job like this; I didn't even have a vertical slide or dividing head so I was really up against it.

I'm as stubborn as they come and I was going to get this winder working however long it took so lots more researching; I found out how to make a single point cutter of the correct Involute tooth profile but typical of my luck just one cutter wouldn't cut all the gears I needed a set of four correctly profiled cutters so I made four. Now I needed to mount the cutter and did so using a heavy length of BMS (round bar stock) between centers with the cutter mounted on center. Now I needed a way of engaging the cutter so I made my own vertical slide from offcuts of metal I had to hand; yes I'm tight. No dividing head so what could I do to index the blanks; I'm useless with CAD and tried lots of CAD programs finding it difficult to draw a straight line; the lines were zig-zags; then I found;

FREE CAD Software | Design Custom Parts | eMachineShop

WOW I was amazed to find emachineshop showed a "Spur gear wizard" I couldn't even draw a straight line but this got my full undivided attention; after lots of playing around sussing out how to use the wizard I finally printed of a gear drawing but it was 8" diameter? What now and how do I sort this out; simple once the answer is known; print to actual size not print to fit page; further to this I found I could adjust printed line width so now I had my first gear paper template; this is what I had dreamt up; I intended to uses double sided self adhesive tape to attach each paper template directly to the face of the prepared gear blank; I took a great deal of care to get this perfect. I turned a mounting boss securing the gear blank to the vertical slide and set about cutting my very first gear; I was very apprehensive indeed never having seen this done and knowing the lathe was rubbish.

I successfully completed the first gear the indexing being directly between the cutter tip and aligned with the template; it's surprising just how accurate this proved to be and certainly accurate enough for my needs. I then wanted to go further and make a set of cast iron gears; I visited Blackgates Model Engineering and had poor Duncan cut 45 Meehanite cast iron blanks; at the time I think the blanks cost £80 plus £10 because of the time spent in cutting which was very reasonable; I had the blanks cut slightly thick allowing facing in the lathe.

I took a big gamble with the first cast iron blank; I had faced it both sides and brought it to correct diameter; I set the cutter to give full depth then dropped the vertical slide down; with the lathe in motion I did as previously and very slowly wound the blank up into the cutter; I was absolutely amazed to see the slot appear as if by magic; it's the slot each side of the tooth which is cut; now I really got stuck in and could cut a slot in less than a minute each; the problem now was I was so fast at starting and stopping the lathe the motor expired in a cloud of smoke; no problem I replaced the motor and cracked on. Single phase motors with capacitors don't like frequent start/stop cycling.

With 45 gears now successfully cut I needed something to keep them together or these too would become separated and lost just as the original gears were; I designed and made a bespoke comb jointed wooden box and even dreamt up my own method of making a brass nameplate.

I'm not the sharpest tool in the kit and I'm not smart or expert in anything; I made many frustrating mistakes along the way but I gained knowledge through each mistake; I've never seen gear indexing done previously using a paper template the way I did so I'm pretty sure it's unique to me as is my method of making the brass nameplates. I'm just downright stubborn and too stupid to quit and walk away when things go wrong; I've never failed yet in any project or job I've attempted and feel the only way to really fail in anything is not to try. I hope my ramblings are of interest.

Kind regards, Colin.







The AVO wave winder as bought. It was expensive scrap but how I like to be challenged and this proved to be a long challenge indeed.






The winder was seized solid with rust; here I've applied oil and managed to remove components.






The main shaft simply didn't want to budge; I tried heating but in the end resorted to making the clamping lever from offcuts of steel; I needed to exercise great care because to break the casting would be a disaster; with more heat and this time pressure applied I finally removed the shaft much to my relief.






emachineshop spur gear wizard was used here seen a number of paper gear templates together with hole punch I turned to ensure alignment on the vertical slide. 






Here a pair of gears being cut; I took advantage of this when two of the same size were needed in the gear set.






Here is the cutter tip being indexed against the paper template; it was so amazingly simple and worked a treat; the bottom set screw locked the mounting boss and the top set screw allowed rapid indexing it was a very solid mounting.






Not having an expensive vertical slide wasn't going to stop me; I made this from odds and ends I had to hand; it proved very accurate once set up and adjusted; the lathe carriage was securely locked so all I needed to do was to determine depth of cut on the first slot then it was just a case of indexing and lowing the slide to clear the cutter; with the lathe in motion raising the slide engaged the cutter and in less than a minute a full depth slot was cut; the 60T gear took less than an hour.






After many hours researching and testing my dreamed up ideas here are the gears at home in their bespoke wooden box.






Having gone to so my effort it was only right that I should fully complete the job to the best of my ability so I decided to experiment with yet another new idea in making this brass nameplate; all the letters etc. were cut out using a fretsaw with piercing blade fitted; fiddly and time consuming but I'd come this far so what's a bit more time. Super glue was used and then it was all sprayed black from a rattle can; a full sheet of wet or dry abrasive 240G was placed on a planer cast iron table and the plate rubbed upon the abrasive paper with the result shown; to complete it a coat of clear lacquer was blown on from a rattle can.

I hope all this makes sense because it takes a lot of time putting a thread like this together; it covers the main parts but when I did this project it was very involved indeed as I tested my ideas out; as I say I like to leave my comfort zone and try something new; I must be barking mad but I'm never bored.


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## SammyQ (13 Jan 2021)

My Diety, that is superlative. May I please say it is also an emphatic demonstration of: " it ain't wot y' got, it's 'ow y' use it"!!



Sam


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## pcb1962 (13 Jan 2021)

That's a real achievement, congratulations. I have to admit that although I have a fully equipped machine shop I have never cut a gear in 40 years of metalwork.
On the electronics side, I'm a big fan of Mr Carlson's Lab on YouTube, he does some incredible vintage radio restorations and I find the depth of his knowledge of the subject just mind blowing.


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## Phill05 (13 Jan 2021)

This is what I love to see great work keep it up you are an inspiration so stick at it.


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## TFrench (13 Jan 2021)

Amazing stuff. Have you got a picture of the completed coil winder?


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## Retired (14 Jan 2021)

Hi,

Thank you for your replies and kind comments; much appreciated. Thanks also for Mr. Carlson's link pcb1962 he sure has some kit around him.

It's good of you to ask TFrench; yes I'm happy to post more pictures; I'd like to encourage everyone doing projects of any kind to take pictures of work in progress; I've been doing this for years and have thousands of pictures on file these just a few of them. I have an SLR camera that I seldom use it being rather big and bulky and if I damage it in the workshop it's expensive to replace so for general use I like my pocket sized Kodak PIXPRO FZ53; I keep this Kodak in a small camera bag I bought through eBay to keep it clean and out of the dust;

Buy Kodak PixPro FZ53 Mirrorless Camera With 5.1-25.5mm Lens | Compact digital cameras | Argos

I'm not a camera expert but this little Kodak has been and still is brilliant; easy to use and slips into a pocket.

Back to the plot; here are more pictures in random order;






The aluminium wire guide arm was broken so I made a new arm; the circles seen are the result of "Fly" cutting in the lathe to bring it to correct thickness; hand cutting with a hacksaw and filing brought the correct profile; I was taught to use my head and hands to make anything.






I must add the above picture it being one of a number very kindly sent to me by a forum member who had a working clone of my winder; the pictures did help a great deal showing how the gears were arranged and more to the point actual gears; this was on another forum specializing in vintage radio's.






Nearing completion after its rebuild showing a gear train installed and fully working. The new gears will bed in nicely; a bit noisy at first but once run in and adjusted will quieten down; I tried all the gears to ensure there weren't any problems.






The rear view after the rebuild.






The front view after the rebuild. I was pleased to reach this stage and it had already taken a lot of time but without gears and other missing parts the winder was still little better than scrap; now I was really in for it having never cut a gear; sorting the gears out took a great deal longer than the rebuild; I've rebuilt many machines but never done gear cutting and 45 gears were needed; I like a challenge though.






The crank was missing so I made a new crank; the turned oak handle revolves on its shaft; no job too small to command my best attention. I have the necessary kit like wood and metal lathes plus welder; the crank was made of offcuts I had to hand; I don't throw away offcuts and seldom seem to use them up; they just get smaller.






A knob was missing so I copied the pattern from a knob that was with the winder; just another enjoyable job which I enjoyed; I like making new things from scratch.






Parts I made; the top spindle has a "live" center; the threaded item is its locking device in the tailstock; the new knob screws onto the thread allowing adjustment of the spindle then locking it in position. The new knob I made on the right; it being smaller but didn't cost anything it being a short bar end of aluminium and it does the job looking the part.






A decent paint job made a lot of difference.






What this thread is about and what a relief it was to finally complete the gears in cast iron. I can usually solve a problem but why do I have to wake around 3am in order to dream up idea's but at this time each morning I can think with great clarity without interruptions of any kind; Gears cut with the aid of a paper template for indexing but the idea worked. I felt deeply humbled to receive an award for my efforts after submitting and having published the story here shown on the page index at 43.

BVWS Bulletin Volume 34, Number 4 (Winter 2009) - British Vintage Wireless Society

I've often seen expensive equipment being used when very basic kit can accomplish the same job; I recall a radio I was repairing for a friend it being a vintage PYE; this had lots of Mazak rot in its castings but also in an important component this being the spindle of the tuning gang; the spindle had broken hence stations could no longer be tuned in; at the time I had a big Colchester Triumph engineering lathe which was an overkill for such a small job; I didn't have an expensive dividing head but the spindle needed very accurate flats adding; all I used was a woodworkers sliding bevel adjusting this against the original spindle and transferring the adjustment very easily onto the new brass spindle I was making; I completed the job very easily in a morning and brought the radio back into full working order thinking little of it it just being another interesting lathe job. A short while later on a forum two members were involved with restoring a clone of the PYE radio I'd restored; the owner to do the cabinet restoration his friend to make the new tuning gang spindle which had broken just as the one had I replaced; I watched with interest as the friend with a Colchester lathe and a dividing head set about making the spindle; he produced top class CAD drawings of the spindle adding every dimension making a top class job of it but months later was still beaten in making the new spindle; he was playing around with the complicated dividing head. Years later I still don't know if the cabinet and chassis were reunited. I've said many times I'm not smart or clever but I was taught by top engineers to use my head and hands to make things; these were genuine old fashioned engineers not fitters; I'm indebted to these engineers for showing me how to make just about anything from scratch with very basic kit.

I'm not scared of trying anything new or making a fool of myself at least I'll have a go and have yet to fail; those who say they can't do anything are correct.

It's snowing hence I'm once again being a keyboard warrior but once I'm allowed to play out I spend little time at the keyboard; I've got many interesting hobbies to occupy my time; I'm about to play with my Peter Child pyrography kit I bought about two years ago but never got the time due to more pressing jobs; I've just bought a picnic table through eBay and I'll set this up in my small office where it's warm and dry; I've cut up a ply sheet 4' x 2' x 1/8" into practice sized pieces and fully sanded them so I'm looking forward to yet another new hobby.

For members unfamiliar with pyrography here's an example; I want to apply pyrography to my woodturning. Life is so full of interesting things to have a go at.


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## clogs (14 Jan 2021)

Thanks Colin for the whole write up.....you certainly are gifted.....
also thanks for the Pyrography vid......that lady has skill......
My Siamese is sleeping on my lap right now.....
He "Gerorge" is now the firms cat...was up the scoffolding this morning being supervised by george....
when I'm in the shop he finds a place to watch and sleep.....

For those that dont know Siamese cats are very dog like.....they will train, go for walks if u want and if you are stuck at home
they will not need to be taken out for exersise plus the conv of using a litter tray.....
George and his sister, not bad for being found in a skip at a few days old.....


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## Tris (14 Jan 2021)

Reading this there's an old phrase I'm reminded of- 'genius is 1% inspiration, 99% perspiration'. 
Thank you for a very enjoyable read


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## steve355 (4 Jun 2022)

Awesome job, with improvised kit - well done. Ive been doing mine the “proper“ way… I bought an old Burke #4 horizontal mill as a bit of a wreck, restored it, then. I got a VDH dividing head and refurbed that too.

My end goal it to make a tail vise for my woodworking. I know those don’t need gears, but it’s all for fun, and I want to use bevel gears to put the handle on the front of the bench.

See also a practice acme screw I cut for the vise.

I haven’t got it all quite right yet but nearly there.


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## Ozi (4 Jun 2022)

Most excellent, you are truly worth the name Engineer.

I have seen people make gears by indexing against a paper template - usually for wooden clocks and using a band-saw 

I'm sure people on here will know this name but it's always worth having a look






Wooden Gear Clock Plans by Clayton Boyer


Wooden Gear Clocks and Clock Plans



www.lisaboyer.com


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