AVO Douglas wave winder.

[Mr Moose]

Hello,
Tracy tools, www.tracytools.com/cuttersinvolute.htm, claims to have gear cutters for 2DP - 120DP for £18 (+vat). They also do some CP sizes.
Oddly enough I have the other 36" Myford MF lathe. Its previous owner, who had it reconditioned after the war, said it was used to machine gun barrels in the war.
'Tufnol' can be stronger than some people think. My brother and I have a low loader trailer (used to carry our little 7ton traction engine) the twin rear axles of which can carry up to 25 tons in total, are carried on a pair of 'Tufnol' bearings.
Yours, Richard

[kalee20]

Originally Posted by David Tilley

I haven't a clue what 'Tufnol' is...

Paxolin, SRBP, SRBF.

Synthetic Resin Bonded Paper / Fabric (usually brown phenolic resin). Many different grades according to cost, application, whether sheet or rod or tube etc. Cotton fabric very popular, also flax (linen), glass-fibre, and asbestos in the past.

Advantages for gears are largely self-lubricating, silence - and bringing back on-topic, you won't get little metallic grindings from exposed gears embedded in your wave coils!

[Retired]

Hi, The book on single point tool sounds just up my street Alan; I'll look forward to your PM.
What an idea Colin, white gears to match I wouldn't dare use it in case I scratched it in fact it's a pity to get it dirty. It would look good with alternative ivory gears (in my dreams).
David I would love to wind your LOPT but have only done one as an experiment recently and have a long way to go yet as I still need to finish my winder off then learn how to use it. I have a number of friends also waiting for production to begin. Long term I wonder if it would be possible to set up an exchange scheme for the popular ones but at much cheaper prices than I've heard quoted, it would be such a pity if sets got scrapped due to the cost of a LOPT rewind. My LOPT rewind is due to be published in the autumn issue of the Bulletin.
Richard your Myford MF brings the tally up to three now; if you are interested I can dig out the website that gives quite a bit of information on these lathes, mine needs some work doing on it as the carriage is manual feed only and it looks to have some parts missing. Please PM me if you would like the website.
Kalee yes good point about metalic grindings as they get everywhere.
Does anyone know if Tufnol is toxic?
After all the hours put in on the winder it's wonderful just to sit back a bit and admire the precision engineering that went into making it originally.
The world would be a better place if everyone had an hobby. Thanks everyone for all your comments, Col.

[John M0GLN]

Originally Posted by Retired

Does anyone know if Tufnol is toxic?
comments, Col.

This is the link to the Tufnol website http://www.tufnol.com/tufnol/default.asp there's a lot of technical information, pages on gear design etc, they also publish Health and Safety sheets here http://www.tufnol.com/tufnol/default.asp?id=120.

I've machined Tufnol, turned and milled it, and find the dust ( from Carp brand ) slightly irritant and would always wear a dust mask.

John

[Retired]

Hi John, Thanks for this I'll have a look at the sites as you can't be too careful when it comes to safety in the workshop. I once used the grinder to shape some small flanges for a bobbin out of formica and the following three days I was extremely ill with a terrible headache and feeling sick. Thanks again, Col.

[kalee20]

Well, phenol itself is toxic (it's the basis for some antiseptics). Plus, in the form of small dust, I would not want to breathe in Tufnol, don't want farmer's lung invading our hobby!

[Retired]

Hi Richard, (Mr Moose). Here are the websites covering our Myford lathes. Our two MF36 are the only known survivors. This might also interest other forum members who are lathe owners.
http://www.lathes.co.uk/myford%20mf74/page6.html
http://www.lathes.co.uk/myford%20mf74/index.html
Col.

[glowinganode]

Hi, my old meddings pillar drill has tufnol gears in the reduction. Machine is fitted with 3/4 hp motor no trouble at all. Last time I cut a gear in the lathe I used a different method to you. The blank disk was mounted on a mandrel in the chuck. A suitably ground tool was held in the toolpost, but rotated 90deg so it cut towards the chuck. The gear was indexed round by using a suitable change wheel and a stop. Taking about .002" (.05mm) cut at a time using the carriage traverse handle. Have also produced splined shafts in steel using same method. Painstakingly tedious but works.

[Retired]

Hi Glowinganode, (great name) Thanks for this; yes it is an option that does work and I appreciate you bringing it up. The smallest gear is 24T and the largest 96T and given the 29 gears in the set this method would take forever; for the odd gear it is a viable solution and certainly worth considering.This method is also good for producing keyways. I'm still experimenting but have now produced two 60T Tufnol gears using my method cutting the full slot in one pass with incredible ease and speed. My set up will produce up to four same size gears at once. I will beg the forums indulgence and hope to expand on this subject in the near future but here are a few pictures of work in progress. Any ideas or comments are very welcome. Best wishes, Col.

[Mike Phelan]

That's a neat idea, Col - you're using it without any sort of division plate, then? Just indexing it with whatever is attached to the vertical slide? Brilliant!

PS: I'll reply to your email you later when I've caught up.

[Retired]

Hi.
What a project this wave winder turned out to be. I thought most of the work had been completed once the winder was reassembled but I was totally wrong. Making the change gears completely took over my life for about a month. At first I was completely lost as I had never cut a gear before and information about the gears was scarce. I was delighted to receive a workshop manual from Harold who generously sent it FOC. At first I skimmed through it and thought 28 gears were needed. This has since been proved wrong as reading the manual later revealed that there are in fact 45 gears in the complete set. This was going to be a headache.
There are three lots of gears these being; nineteen Wave Compound Gears, eight Wave Form Gears and eighteen Traverse Gears. These were originally supplied with each machine as standard with other gears to order. At that point I thought I’d better not read the manual any more as the job was getting bigger.
I received a lot of most welcome help with information from forum members and John as stated previously helped a great deal by sending pictures of the gears on his own winder together with gear dimensions. I also received lots of other information including various websites but now with the new information things started to get out of hand as I was getting overwhelmed by a lot of technical details. I couldn’t sleep on many nights with gears running through my head but slowly I made all the mistakes possible and fell into every black hole until things started to become clear.
I fabricated a vertical slide out of scrap at little cost. I found that a website I had used a few years previously contained a gear wizard which proved a huge help. I bought Tufnol thinking this would be easy to machine and eventually made six Tufnol gears that worked very well. The amount of technical gear data I now had was scary and contained lots of formulae; terms like DP, PA, PCD, Module and Involute curves all added to my confusion. Hours were spent experimenting with the gear wizard (emachineshop) and printing the drawings off but at first nothing appeared to add up until I found out how to use the DP; this being the diametrical pitch whereas I had been using the PCD (pitch circle diameter) the fog finally cleared and using a DP24 everything fell into place. By this time experimental Tufnol gears had been cut but it was hit or miss as sometimes the gears were too large other times too small. I was cutting the 60T pair of wave form gears and these had to be correct as they were mounted on fixed centers. Little things started to come right and when I stopped complicating things and settled down I realized that I had all the answers in my hands; the drawings being the gears; even this at first wasn’t fool proof because I tried to overlap the drawings in order to get the fixed centers correct but once the gears were cut they still didn’t fit. The tooth depth was evading me but once the drawings were put together in such a position that the teeth were in full mesh and the centers where measured and found to be correct then the gears turned out perfectly. I now started to enjoy gear cutting and wondered how my method would work cutting cast iron gears as I didn’t really like the look of the Tufnol gears on this machine.
I visited Blackgates Engineering and ordered eight cast iron rounds waiting for them to be cut by Duncan. The cutting was a slow process and I was there over two hours but passed the time chatting to other customers who came and went; at one point Duncan said he thought I looked like the professor in “Back to the future” to which another customer remarked that it wasn’t bad enough leaving the premises with empty pockets but we get insulted into the bargain!!! It’s this sort of thing that makes our hobby so worthwhile and now when I e-mail Blackgates I sign myself the mad professor.
Cutting the gears in cast iron has turned out to be extremely easy but once I got into the swing was struck by a number of problems. Using the Tufnol I didn’t need to face it in the lathe but the cast iron blanks required facing; I had faced a number of blanks but eventually found I was making shallow cones as the lathe was over 15 thou out whilst facing? I had bought this very rare Myford lathe at the start of the year and it was advertised as in good condition. I tried to swing the compound slide but it wouldn’t line up. I then gripped the chuck in both hands and gave it a good tug to find a lot of play in the plain bearings together with a good deal of end float. This was worrying because I knew these lathes to be prone to breaking the headstock casting if the adjustment was clamped down tight so I proceeded with a lot of caution; the end float was easy to get rid of but as I nipped the adjustment up on the main bearing I found that it would adjust until there was slight drag in the bearing but there remained play to and thro which I thought could be due to the bearing wearing oval? The adjuster was backed off slightly and the headstock was then rotated to align with the saddle to enable the facing to be completed.

As the very last large blank was being faced the lathe started to chatter; the lathe had been playing up as sometimes it would take a heavy cut and other times struggled with a cut of 10 thou. The lathe was now starting to annoy as I had been nursing it along and wanted to finish this job before I fell off my perch. I was not at all amused to find the headstock casting had broken right across the main bearing after using a rag to wipe it down for inspection. The headstock was then completely stripped and removed from the bed. The following day I was running around local firms to try to obtain cast iron welding rods but to no avail as it was a Saturday morning and industry shuts down in England for the weekend!!! Fed up at wasting my time I returned home and made temporary repairs by welding up a steel clamp to secure the broken casting. The last gear was successfully faced then the headstock was re-aligned with the tailstock and all the bores were drilled.

I had fitted a 2HP motor to the lathe as the motor supplied was only 1/4HP; I set to with a vengeance and really started to knock out the gears; I had become so proficient that I could index and cut a full depth slot in 45 seconds each and continued to do so for hours on end until the motor decided enough was enough and packed in. I didn’t like this motor anyway as it was quite noisy and sounded rough so I stripped the useful bits from it and scrapped the rest. I selected a 3/4HP from stock and fitted it and resumed work; the temporary headstock repair held up very well and I completed 44 cast iron gears. There is still one gear outstanding and this is the daddy of them all at 96T but I need to specially order the blank as Blackgates don’t stock the bar size required; having already cut a 90T gear this last gear won’t be a problem.
One important point missed is the cutter. A single point fly cutter was used throughout mounted between centers in a 1” diameter bar secured with a grub screw. The cutter is a piece of 3/16” diameter tool steel ready hardened and tempered; it cost £3 and was cut in half. A lot of thought went into how to generate the profile; I had bought a book called Gears and Gear Cutting by Ivan Law which gives Involute curve data and how to achieve it but this involved making a cutter then having to harden and temper it which didn’t appeal to me as I already had a tempered bit of tool steel in my hand. After yet another restless night I came up with the idea of having a go at dressing a small grinding wheel to the correct diameter across its face then presenting the tool to this thereby imparting the correct involute curve to the tool? This appeared to be an easy solution and went on to prove so. I paid £2 for a 3” x ½” white plain grinding wheel and mounted this on the small woodturning lathe to which I added a grinding rest. A gear drawing was printed out but at full page size and the angle was measured between two teeth which I halved and made a paper cut out to use as a gauge. The cutter was ground to a point at this angle giving the basic shape then using the data from the book the grinding wheel was dressed using a devil stone to match a certain number of gears; involute cutters can be purchased readily for about £20 each but there are eight to a set for a given PA. To accurately dress the wheel a semicircle was drawn on a strip of mild steel and this was in turn filed as a gauge; the gauge was then used to set the profile on the wheel which was one job I disliked due to the dust. The first attempt was disappointing as I misunderstood what was required but with practice I found that by presenting the cutter across the face of the wheel a distorted curve appeared rather than a true arc; now I understood and with a little experimenting and comparing the cutter to the gear drawing I could produce a reasonably accurate profile with little difficulty; this proved far superior to trying to off hand grind the cutter profile; I had also spent a couple of hours previously making a cutter holder out of bright mild steel square bar; this holder was accurately set up in the four jaw and bored to 3/16” diameter and when tested using a DTI was found to be only two thou out on all four sides. I later modified my gauge making by drilling a suitably sized hole in steel strip and using a hacksaw cut straight through the strip on the diameter center line.

Once the gears had been cut then a small drilling jig was made to enable the two small driving holes to be accurately drilled in each; these holes align with the driving pins of the shaft dogs. The teeth number was then stamped on each gear and the final job this morning was to remove the remains of the paper drawings by using turps to soak them allowing them to peel away.

I’ve never seen this method of gear cutting used and have visited many websites. Apart from the cost of the gear material the whole set up has cost peanuts, the vertical slide works beautifully and to answer Alan’s question; yes the indexing is done directly from the drawing on the gear blank; each time the gear was indexed the lathe was then rotated by hand to ensure the cutter was clear before switching on. The blanks were assembled into small batches to match as each involute profile was added to the cutter; the same bit of tool steel was used throughout and was remarkable in the way it held up to the considerable punishment it received without needing sharpening as each batch was made. The cutter went through the cast iron as though the iron was butter and seemed to scoop out the waste rather than cut it leaving a pile of tiny chips rather than dust; as the cut commenced it was extremely easy to see if the cutter was centered because it initially cut a “V” and as the cut progressed it was impressive to watch the waste material being removed very neatly between the lines on the drawing. The faces of the teeth are left without tool marks and are shiny.

This is only the tip of what I have been up to for the last month regarding this project and to fill in every detail would complete a book. I’m aware that this gear cutting is engineering but due to it being so necessary in completing the winder felt it appropriate adding it. I can only once again sincerely thank everyone for their kind help and will add that I’ve made a number of new friends along the way. My next project is to fully restore the Myford Lathe which can be forgiven the problems due to it being 67 years old; I’ve already bought Whale Tufnol to make new headstock bearings with at a cost of £15 cash after being quoted 2p short of £145 for a single bearing from Tufnol in Birmingham and I’m researching how to scrape a lathe bed but that will be for another forum. I intend to do a proper write up on this project in the near future and submit it for the editor’s consideration for publication in the BVWS Bulletin. Many thanks for your patience and interest. I love a good challenge. Kind regards, Col.

[Ed_Dinning]

A true engineer sir! To make a tool to make the tool, to do the job.
Let us know how you get on when coil winding.

Good luck, Ed

[coil1234]

I would like to second the above, fantastic, reassuring that such skill, devotion and knowledge is still around, a true engineer indeed, more power to your headstock.

Mike A

[AlanBeckett]

Mike,
Col's Headstock is broken, but I have every faith in his ability to fix it
Alan

[Retired]

Hi, Thanks Ed and Mike A for the kind comments and also Alan for the encouragement and who I know has had similar bearing problems on his machines. At last I can add the final update as the headstock is now repaired. I took the mandrel to Metallizers who made a superb job of restoring it to original dimensions after first metal spraying it with hardened stainless. Before stripping the headstock I turned new bearings from Tufnol but had to spend over four hours adjusting the lathe before it would bore a parallel hole using a boring bar, with a great deal of patience a pair of perfect bearings were turned. I chucked two lumps of cast iron in the four jaw and faced them before boring to exactly 1.5" diameter using the boring bar these were to be the new bearing top caps. Many hours were spent using an hacksaw; file and engineers square adding the outer profile to the caps which were then bored for the mounting bolts and for the addition of new oilers. The next job took a great deal longer and that was to cut and file the headstock accurately to accept the new bearing caps; I don't have a milling machine but was taught how to file to a "thou" during my apprenticeship but it was hard work as only short strokes with the hacksaw and file could be used. I fitted the top caps today and am now delighted that everthing fits as it should; I'll buy a couple more studs for the front and will use self locking nuts for adjustment. The first picture shows the temporary clamp securing the broken casting and the second picture shows the new gussett welded in. The rest of the lathe restoration is beyond the scope of this forum as it is pure engineering but I hope my story has been interesting and unusual. Col.

[AlanBeckett]

Col,
A splendid job!
I'm afraid I left my replacement bearing cap like the bottom one in your third picture. Perhaps I'll bring it up there for extra fettling
Alan

[Retired]

Hi, Thanks Alan you're welcome anytime; bring a big file with you.

Today is very special because I've now wound my first experimental coil (pie) using the wave winder. I only have one bobbin of silk/cotton covered wire at 0.007" thick and the covering is rather fragile with age but it worked. I set the winder up for single wave form with a pair of 60T gears and compound gears of 44T; 29T; 32T and 48T. The former is a bit of hardwood turned on the woodturning lathe and accurately centered. Not having a correct wire feed the bobbin of wire was placed on the floor for this experiment; tension being applied by hand as winding progressed. The result was better than expected and now the basics are understood by me all I need is a lot of practice. The winder is a fine machine and I'm happy to see it in full working order; the restoration project took quite a bit longer than expected as I had to repair the broken lathe headstock in order to make the few missing components for the winder which are shown in the picture; these being a revolving cone center and rod; rod locking clamp; brass wire guide button, not shown and a locking knob; the smaller knob is the home made one; the knob was roughed out on the lathe and the "indents" hand filed then it was returned to the lathe for profiling; it turned out well and matches the other knob. I tried many times to take a decent close up picture of the finished coil; in the workshop; garage; kitchen; front room and outdoors but these pictures are the best I could achieve.

Unfortunately the winder will be shelved for a while as I have spent a great deal of time working on it and would now like to catch up on other projects and work around our home. A number of forum members already know I'm planning to add a thread on French Polishing and I'd like to sincerely thank them for their most welcome encouragement. A good day indeed. Col.

[Mike Phelan]

We've just been to see Col's winder restoration last week; what a superb job, and the cleanest workshop I've ever seen.
We look forward to the French Polishing thread, having seen his radio cabinets - they certainly put some of mine to shame.

[Retired]

Hi, That's very kind of you Mike. I like my workshop to be tidy as I spend a lot of time in there and clean up as work progresses. I'm waiting for my new digital camera to arrive which has been delayed by the forthcoming postal strike before I can add the thread on French Polishing that more members are encouraging me to post. Col.

[Retired]

Hi,

I'm absolutely delighted to have been awarded The Geoffrey Dixon-Nuttall Award Best Restoration Article 2009 AVO Wave Winder Restoration. (BVWS).

I feel truly humbled and honoured at such an award which came as a total surprise. the restoration of the winder afforded me a great deal of pleasure and I was happy to share my story; this award is the icing on the cake and will encourage me to do even better.

The award is a lovely item and I'm pleased to add pictures of it; I've never seen one before and I will always cherish it.

Kind regards, Col.