Replacement Change Gears for 12” Geared-head Lathe

This not exactly “homemade” because I started with manufactured spur gears and modified these to fit my lathe. I have the situation where replacement parts are no longer available and I have to either make or modify the parts.

I have a used 12” x 37” geared-head gap bed lathe that came with the wrong change gears for cutting imperial or metric threads. The lathe has two spur gears located in the compartment behind the spindle that must be changed when switching between cutting imperial and metric threads. When I acquired the lathe it had an odd set of 32 tooth and 46 tooth spur gears for cutting only 11 ½, 23, 46 and 92 TPI and nothing else. Missing were the two 40 tooth gears required for imperial thread cutting and a 30 tooth gear for cutting metric threads. Luckily, the lathe still had the 120/127 combo gear essential for either imperial or metric thread cutting.

My geared-head lathe was built in Taiwan in 1987 but it is very similar design to the 12” swing Grizzly lathes. I called Grizzly but they could not provide the specs to the gears other than the number of teeth. I took a chance and the ordered replacement gears. The Grizzly gears did not fit because they use a 14 ½ degree pressure angle and I needed 20 degree PA and a diametral pitch of 20. Boston Gear makes steel spur gears in their YA series that fit my specs and I ordered the gears with 0.500 bores.

I machined the gears to be 10 mm wide on the teeth and 10 mm wide on the hub using an expandable mandrel with a slotted brass tube to fit the in between mandrel size. Next I bored to 18 mm ID by chucking the hub section and not touching the gear teeth. Finally I broached a 5.01 mm wide x 2.51 mm deep keyway to fit my lathe shafts.

I made a “broaching” tool using a HSS cutting tool blank ground to cut the keyway using a boring bar and having the lathe chuck locked in place (and turned off). I used a digital height gage to align the horizontal direction and height of the broaching tool. After creating the keyway slot, a 0.1970" (5.004 mm) gage pin was used to check the slot width before removing the gears from the chuck.

These are not exactly “homemade” from scratch but the gear modifications allowed me to install the exact parts I needed for this lathe. Now the lathe has all the necessary change gears and a quick change gear box combinations to cut a wide range of threads from 3 3/4 to 112 TPI and 7.5 to .25 mm pitch (see attached threading chart showing the change gear sizes and placement options). The two 40T change gears normally drive the 120T gear for most imperial threading and the lower 40T gear is reversed on its shaft to drive the 127T for metric threading.

The change gears are lubricated using a high press grease and run almost silently. The grease product is "Dart LUBE CMD Extreme Pressure Lubricant" (see https://www.amazon.com/Dart-LUBE-Ext...sure+Lubricant ).

Thanks Paul! I've added your Change Gears to our Lathes category, as well as to your builder page: Paul Jones' Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="/change-gears"><img src="/uploads/113486/change-gears.jpeg" alt="Change Gears" /></a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="/change-gears">Change Gears</a> <span> by <a href="/builder/Paul+Jones">Paul Jones</a></span> </div> <div class="tags"> tags: <a href="/tag/lathe">lathe</a>, <a href="/tag/threading">threading</a>, <a href="/tag/gears">gears</a> </div> </div> </div> </div>

Very interesting post! Learned something.

Update to the gear head lathe change gear remake,

Last week I cleaned and replaced the change gear grease on the gears at the rear of the lathe headstock with the product "Dart LUBE CMD Extreme Pressure Lubricant" (see https://www.amazon.com/Dart-LUBE-Ext...sure+Lubricant ).

This is sometimes a recommended lubricant for lathe dead centers but the sound dampening effect it had on the lathe change gears was truly amazing. The gears went from making a reasonable whirling sound to almost no sound at all. Try it and I think you will see a major difference in the change gear sound.

Thanks for looking,

Paul Jones

Paul,
that hi pressure lube would be nice but it's your side of the pond, trying to get it here via mail without doubling the price !

any of of the brit / euro crew know of an outlet this side of the water? or a "local " equivalent ?

I remember back in the day i used Bel Ray EP2 Termalene grease I brought a small pot back to the UK, but that has long since gotten used up. Tried to find a stockist in the UK but no luck (unless i want a drum of it :-)

Ideas?

Hello Paul,

Nice post. Thanks for sharing.
You can also order gears via aliexpress. Unfortunately you can't buy them cheap in China like I do, but should be much cheaper than Grizzly - chinese gears.
I am presently buying 1.5 module gears for my next project - external lathe headstock gearbox. 16 gears - 4 shafts - 18 speeds. These metric gears are coming as follows: M1 - width 10 mm, M1.5 - width 15 mm, M2 - width 20 mm and so on.

Regards
LMMasterMariner

To: Y-Geo,
I was introduced to the Dart LUBE CMD Extreme Pressure Lubricant from a recent YouTube video by Keith Fenner. He mentioned that his tube of the lubricant was probably his second tube in a lifetime of machining because it is used very sparingly. Instead of paying $9.05 USD you might have to pay $20 USD with shipping but it is not going to brake the bank when it lasts practically a lifetime.

To: LMMasterMariner,

Thanks for the tip on buying from aliexpress for 1.5 module gears.

I bought my spur gears based on the YA series from the company Boston Gear instead of buying from Grizzly because the gears from Grizzly did not fit my lathe (Grizzly had 14.5 degree pressure angle and I required 20 degree PA). My gear head, gap bed lathe was built in Taiwan in 1987 but I discovered it has some Imperial dimensioned parts including the gears while the shaft diameters are exactly metric (some 18 mm). At first I though the gears were based on 1.5 module gears because I thought a lathe built in Taiwan would be basically all metric. After careful measurements of the existing gears, I determined the gears were actually 20 degree PA with a diametral pitch of 20. The gears sold by Boston Gear are USA made and very high quality. Instead of buying directly from Boston Gear, I searched eBay, found the exact Boston Gear gears I needed, made a fair offer and purchased the gears from new stock for $20 USD each with shipping. I still had to machine the hub and tooth widths to be smaller and broach the gears using this method ( http://www.homemadetools.net/forum/b...7110#post23249 ) because I did not own a 5 mm wide broach.

Thank you for the information.

Paul

A lot of machinery that came out of Taiwan in the 80 were made by companies that shared a partnership with US companies at that time the change over to module gears had not been fully implemented as many of the gears were made in the USA then shipped over the shafts were metric because the bearing industry had already mostly adopted the metric system having the bores and OD's staged in 5 mm increments widths were determined by service duty.

Frank S,

Thank you for the information. Your explanation helps a lot. The bearings on the 1987 Taiwanese lathe were made with metric dimensions and made in Japan. Some of the gears are stamped made in USA and had to be shipped over for assembly. It is a nicely made lathe with lots of hand scrapped surfaces. Despite its age, the run out on the headstock bearings show no measurable TIR when measured with a 0.0001" Interapid dial test indicator.

Paul

My 1979 Victor 16-40 gap bed lathe also made in Taiwan was the same way nice little tool room lathe and as Toolmaker 51 describes a good fit for me after I placed it on 4 inch pads

Paul,
you are right in the greater scheme of things the total cost is minimal but it just T's me off having to pay double/triple + for things because the postage rates from the US are a disgrace frankly.

NEW INFO:-

the supplier on Amazon link will not ship to the UK l and the other two Amazon list for the product also will not ship abroad, mainland USA only

When i built motorcycles i could get the same parts from Australia or Japan even on occasion from Poland where the item price may have been a bit higher but the final price with postage was anywhere from 25% to 75% cheaper than buying it out of the US.

It is almost as though the US vendors do not want the hassle of sending it off to "parts foreign " most seem shocked when i mention that US small parcel (which takes almost everything I wish to buy ) is about 12USD when they are trying to scalp me for 50 + USD postage !

Sorry for the Rant but it bugs me.

Quote:

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Originally Posted by Y-geo

Paul,
that hi pressure lube would be nice but it's your side of the pond, trying to get it here via mail without doubling the price !

any of of the brit / euro crew know of an outlet this side of the water? or a "local " equivalent ?

I remember back in the day i used Bel Ray EP2 Termalene grease I brought a small pot back to the UK, but that has long since gotten used up. Tried to find a stockist in the UK but no luck (unless i want a drum of it :-)

Ideas?

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Contact Us – CMD Lube & Oil

I suggest emailing the manufacturer and see if they have a UK distributor.

You guys know Amazon has a UK website, right?
https://www.amazon.co.uk/Lithium-Ext.../dp/B00CLQM9HS

Try googling "extreme pressure grease UK vendor". I found this, and several other offerings.

hi,
I see that the US condescending tone is still prevalent when dealing with any one who is thought not to be American
Yes we do have amazon and no the brands of grease i am used to using stateside & the one that came recommended were not available thro Amazon .

Thro Google I found a UK agent for Bel ray who was prepared to sell small quantities and also found something that earned a good rep on the race circuit when i was involved in that circle called Royal Purple, so us foreigners are not quite as backward as you seem to believe :-)

I suspect that a lot of the underlying reasons many USA retailers and private venders do not entertain overseas and in many cases Canadian, Central & South American selling may be largely due to the complexity of our export customs and tax laws. Then when you compile the several so called (for our own protection)law enforcement agencies each having their own interpretation of the laws. Makes doing business off shore either not worth the hassle or expensive to do so.
But it works both ways there is a particular brand of bonding adhesive that I had used for years while living and working in several countries that I find almost impossible to get here. Even if I do manage to get it shipped to me it is not the same adhesive that I used to buy. About the only thing it shared was the brand name itself. The bonding strength was less than half of what I remembered.

Quote:

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Originally Posted by Y-geo

hi,
I see that the US condescending tone is still prevalent when dealing with any one who is thought not to be American
Yes we do have amazon and no the brands of grease i am used to using stateside & the one that came recommended were not available thro Amazon .

Thro Google I found a UK agent for Bel ray who was prepared to sell small quantities and also found something that earned a good rep on the race circuit when i was involved in that circle called Royal Purple, so us foreigners are not quite as backward as you seem to believe :-)

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I did not mean to seem condescending. I was, however, quite surprised that it was mentioned Amazon could not supply this kind of grease to the UK because I knew they have a presence there. Just trying to be helpful.

Hi Paul,
I have what I think is the exact same lathe, originally owned by the NSW railways dept. It also came with metric gears missing. Interesting that you should post about your lathe now, because I just took delivery of the missing 1.25 mod gears from Boulton Engineering in the UK, plus another gear to give me 2tpi for a mandrel to create a 10mm pipe coil.

Paul,
You have done an excellent job of altering stock gears to suit your purpose. Very creative way to restore the usefulness of the lathe

old_toolmaker,

Thank you.

I should have mentioned in my original post from 2015 that the Boston Gear gears were bought using e-Bay and not from a USA distributor. The gears were from "new old stock" and it took a while to find them. The e-Bay seller used the buy it now or best offer options. I made a best offer and bought the gears for one third of the then current list price. Later I made the same best offer to the seller for a 30 tooth gear that I was missing and bought it. The 30 tooth gear is for some odd TPI threads that are multiples of 3 3/4 TPI (e.g.,15 or 30 TPI). I will modify the remaining 30T gear whenever I have to single point thread this class of threads.

I would like to post more at HMT but unfortunately I had a stroke last September and now almost fully recovered after being paralyzed on my left side. It was one of those case with 120/60 blood pressure could not predict a stroke problem. I just didn't feel safe in my shop and hence the delay. I am looking forward to posting at HMT.

Regards,
Paul

Hi Paul,
I understand totally what you have been through. I myself had a stroke (brain hemorrhage) and seizure in October 2018 that took me out of the shop until just recently. I lost all vision in my left eye. I was lucky though and regained all my sight over about 9 months. Take care and stay well.

This thread raises an interesting possibility. Could we, as a community not organize a system between us to purchase locally and then forward said items on at sensible postage prices?
I recently bought an armature for a Makita grinder out of the UK because this item is simply "not available, obsolete" in Australia. Freight was more than half the price of the product.

An addendum to my previous post, I, as an individual, can post anything (other than illegal substances), anywhere I please without any government intervention. Whilst clearly I cannot comment on the prospect of similar situations in other countries, I would have expected the same.

Quote:

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Originally Posted by old kodger

This thread raises an interesting possibility. Could we, as a community not organize a system between us to purchase locally and then forward said items on at sensible postage prices?
I recently bought an armature for a Makita grinder out of the UK because this item is simply "not available, obsolete" in Australia. Freight was more than half the price of the product.

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I used to try and send things to friends in Melbourne through the post. Somethings like books and tech manuals would mail with no problems other things like carburetors or distributors not so much fun at all. By the time every pinhead constabulary from US customs to the Au customs got their little piece of the mandatory declared pie in the form of taxes it would have been almost as cheap to try and set up a foundry at Marble bar and made the parts there and transported them across the desert for the antique trucks my friend was working on. But there are things that are the same way trying to import them into the states from Germany like adhesives PATTEX to be exact I find it to be superior to any construction adhesive that can be bought here and that may be the reason I cant get it in larger than 2 oz tubes or I have to buy the Chinese knockoff by the same name