# Missing Change Gears



## crusty_rusty_ (Oct 27, 2021)

I recently Purchased a King Canada 1440B lathe. It came with loads of tooling and machinist tools but after playing with it for a few days I discovered it is missing all the metric change Gears. I contacted the manufacturer who told me they did not stock parts for this machine any more. I also couldn't seem to find the part numbers for the change gears in the manual. I'm sure a good machinist could make these gears how ever I am an absolute beginner so making or modifying gears might be a bit advanced for my first project. I have a hunch that this lathe has been sold under many different name brands and I am wondering if anyone knows enough about this style of lathe to point me in the right direction as to where I could find a set of change gears for this machine. The manual states the metric change gears are 36t, 42t, 54t, 60t, 66t, and two sets of 40t. I will try to get some measurements of the gears today. Any help would be very appreciated


----------



## DAT510 (Oct 27, 2021)

Welcome to H-M

Is your Lathe setup with a Metric or Imperial lead screw?  You are correct that design of lathe has been sold under many names.  I think the most common was the Jet family of lathes. 

If you have an imperial lead screw, then Grizzly Industrial sells the changes gears for metric threading for their G9249 lathe.  They no longer sell the lathe, but still support owners with parts.  My Jet 1024 was missing the change gears too.  I took a gamble and ordered the change gears from Grizzly and they fit perfect.  The change gears from Grizzly have an 18mm ID.









						Parts for 12" x 37" Belt Drive Gap Bed Lathe at Grizzly.com
					

Grizzly Industrial, Inc. is a national retail and internet company providing a wide variety of high-quality woodworking and metalworking machinery, power tools, hand tools and accessories.  By selling directly to end users we provide the best quality products at the best price to professionals...




					www.grizzly.com
				




30T  P/N 1116
32T  P/N 1117
46T  P/N 1118


----------



## B2 (Oct 27, 2021)

I am not familiar with this lathe, but there are lots of others that also have the 1440 in their model names.  I have a PM1440GT, but there is also a PM1440.  However, the 14 and the 40 commonly implies the swing diameter and the 40 the bed length.   And this is what it says in your manual!

Anyway, there are folks who will make change gears for you if you know what you want. They are not complicated.  Mostly the just need to know the thickness, shaft diameter and key sizes, and the number of teeth and type.   I have seen one fellow that makes nice steel ones but I have lost his URL.  Also you can sometimes get them 3D printed (Plastic, see ebay), but they probably hold up for quite .... depends on how often you use them.   

I suggest that you use the lathe for a while and see if you really need them.  Your threading gear box has 8 fundamental threads by 5 (A-E) factors of 2x.  So you have quite a few available already. Very nice and easy to change threading gear box arrangement.   You also already have the 120/127  and the bottom gear that is reversible.  This gives you some more possible TPI gears.  With only one or two other gears you can do several metric sizes, or very close approximations to them.  With only one or two gears you can probably do most of what you might need. That being said you have an English unit lathe so most of the metric threads will not be exact anyway. 

As a newbie it might be informative for you to see what values you can achieve with only one other gear.  I once did the same for a 1970's SouthBend 10 which I got without the metric gears.  I set up an  excel spread sheet.    Also, there are videos on how to do these calculations.


----------



## B2 (Oct 27, 2021)

Assuming you have the English version of the lathe, which the front picture indicates, then your manual's specs says you have an 8TPI lead screw (English).


----------



## AGCB97 (Oct 27, 2021)

I have a 46 tooth gear with a 5/8" bore. You could have it for the price of a flat rate box. It is .630 thick with no shoulder. Wouldn't be hard to bore to 18 mm. It's in as good or better shape than the ones you pictured. You'd have to determine the DP though.
Aaron


----------



## crusty_rusty_ (Oct 27, 2021)

Here are some measurements of the gears. The lead screw appears to be 8TPI.


----------



## crusty_rusty_ (Oct 27, 2021)

DAT510 said:


> Welcome to H-M
> 
> Is your Lathe setup with a Metric or Imperial lead screw?  You are correct that design of lathe has been sold under many names.  I think the most common was the Jet family of lathes.
> 
> ...


thank you for your reply. The lead screw appears to be 8TPI. That is an awesome resource you sent me I will have to dig through the web site and see if they have what I am looking for. I posted some measurements of the gears do these measurements match yours?


----------



## crusty_rusty_ (Oct 27, 2021)

B2 said:


> I am not familiar with this lathe, but there are lots of others that also have the 1440 in their model names.  I have a PM1440GT, but there is also a PM1440.  However, the 14 and the 40 commonly implies the swing diameter and the 40 the bed length.   And this is what it says in your manual!
> 
> Anyway, there are folks who will make change gears for you if you know what you want. They are not complicated.  Mostly the just need to know the thickness, shaft diameter and key sizes, and the number of teeth and type.   I have seen one fellow that makes nice steel ones but I have lost his URL.  Also you can sometimes get them 3D printed (Plastic, see ebay), but they probably hold up for quite .... depends on how often you use them.
> 
> ...


Thank you for your reply. I agree with everything you are saying. It is entirely possible that I wont need the gears I have listed. I sort of just feel a compulsion to make this lathe complete if that makes sense. I will take your advise as I start using the lathe and give that youtube video a watch tonight


----------



## crusty_rusty_ (Oct 27, 2021)

B2 said:


> Assuming you have the English version of the lathe, which the front picture indicates, then your manual's specs says you have an 8TPI lead screw (English).


I measured and it appears my lathe does in fact have an 8TPI lead screw


----------



## crusty_rusty_ (Oct 27, 2021)

AGCB97 said:


> I have a 46 tooth gear with a 5/8" bore. You could have it for the price of a flat rate box. It is .630 thick with no shoulder. Wouldn't be hard to bore to 18 mm. It's in as good or better shape than the ones you pictured. You'd have to determine the DP though.
> Aaron


Thank you Arron that defiantly sounds like a good option and a good project for me. Ill have to figure out the DP of the gears I have.


----------



## B2 (Oct 28, 2021)

I find it a little strange that you have an English lead screw and threading name plate, but have gears that fit a metric shaft, 18mm?  Similar to what @DAT510 showed.  Maybe the lathe was designed for metric and then they just changed the lead screw and the gear teeth numbers to go to English.   You measured 18mm, 10mm, 23mm:  i.e. 18/25.4(*64ths)=.70866(*64ths)=45.35/64.  If it were really an English size I would have expected the number of 64ths to be closer to an integer.  If you have the gears off also measure the mounting shaft(s) just to be sure as it appears that you may have been measuring one of the gears that you had it sitting on top of the lathe in your first pictures.  

Also, why not set the lathe up like the manual might indicate, set the gear box to a thread that easy to measure and let the machine make a light cut (scratch) so that you can see if it really makes the TPI you might expect.  For example, 10TPI, 24TPI,  or others are easy to measure or match to a known bolt.  See pages 9-10 of your manual, and maybe page 13.  Figure 10 shows a picture of your gear positions and at the left hand side of the table shows the gear set up that is suppose to be for that table.  I cannot make out the bottom gear T number, but I looks like the top gear is a 40, the middle gear is 127, and the bottom gear is either another 40 or 48.  Anyway, ratios would be 40/127, 127/127, and 127/46 or 40.  The middle gear only transfers the motion since the same side is use for both of the others.  So the over all ratio would be (40/127)*(127/127)*(127/(46 or 40))=40/(40 or 46).  I would guess that it is the 40.  So the ratio is simply 1!  The manual also says that you have a set of English change gears (page 13) of 30, 32, 46 in the tool box in addition to the two 40's that are mounted on the lathe.  These numbers agree with the numbers that @DAT510 posted.  So on page 13 it also says you would need the following for the metric version of the lathe which would have the 3mm pitch lead screw.  These would not work for  you lathe since the lead screw is 8TPI.

Anyway, from all of the information that you have you can compute a set of tables of gear box gear ratios for every gear box setting. (spread sheet).  Then from this you can figure out the TPI for each of the combinations of change gears that you have more might want.  

You are lucky.  You  have a manual for your lathe!   Although, some of the sentences read like they were written in China, not Canada!  For example it refers to the "lead screw" as "screw leading stick"?  Anyway, the tables look informative.  

Have fun.


----------



## Beckerkumm (Oct 28, 2021)

Do you know what Mod the gears are if metric or the DP or PA if imperial?  You can measure the diameter of one of your gears and look up a chart for the number of teeth and diameter and figure out what you need to match what you have.  That will give you the info to source spur gears from many sources.  Dave


----------



## B2 (Oct 28, 2021)

https://www.engineersedge.com/gear_formula.htm  may provide some of what.


----------



## crusty_rusty_ (Oct 30, 2021)

B2 said:


> I find it a little strange that you have an English lead screw and threading name plate, but have gears that fit a metric shaft, 18mm?  Similar to what @DAT510 showed.  Maybe the lathe was designed for metric and then they just changed the lead screw and the gear teeth numbers to go to English.   You measured 18mm, 10mm, 23mm:  i.e. 18/25.4(*64ths)=.70866(*64ths)=45.35/64.  If it were really an English size I would have expected the number of 64ths to be closer to an integer.  If you have the gears off also measure the mounting shaft(s) just to be sure as it appears that you may have been measuring one of the gears that you had it sitting on top of the lathe in your first pictures.
> 
> Also, why not set the lathe up like the manual might indicate, set the gear box to a thread that easy to measure and let the machine make a light cut (scratch) so that you can see if it really makes the TPI you might expect.  For example, 10TPI, 24TPI,  or others are easy to measure or match to a known bolt.  See pages 9-10 of your manual, and maybe page 13.  Figure 10 shows a picture of your gear positions and at the left hand side of the table shows the gear set up that is suppose to be for that table.  I cannot make out the bottom gear T number, but I looks like the top gear is a 40, the middle gear is 127, and the bottom gear is either another 40 or 48.  Anyway, ratios would be 40/127, 127/127, and 127/46 or 40.  The middle gear only transfers the motion since the same side is use for both of the others.  So the over all ratio would be (40/127)*(127/127)*(127/(46 or 40))=40/(40 or 46).  I would guess that it is the 40.  So the ratio is simply 1!  The manual also says that you have a set of English change gears (page 13) of 30, 32, 46 in the tool box in addition to the two 40's that are mounted on the lathe.  These numbers agree with the numbers that @DAT510 posted.  So on page 13 it also says you would need the following for the metric version of the lathe which would have the 3mm pitch lead screw.  These would not work for  you lathe since the lead screw is 8TPI.
> 
> ...


Thank you for the in-depth response to my post. I got distracted for a few days playing with my Mill and dove back into the lathe today. I re read the manual today for probably the 4th time...and staring right back at me was the error I made. I miss read the manual partially dew to the poor English you touched base on and also my own hastiness.

When the manual is talking about change gears on page 13 it states "The Gear of the lathe that fit for English system screw are put in tool box. Those are (30t, 32t, 46t) each one piece, and have 2 pieces of 40t gear are set on machine.

It then goes onto say The Gear of the lathe that fit for Metric system screw are put in tool box. Those are (36t, 42t, 54t, 60t, 66t) each one piece, and have 2 pieces of 40t gear are set on machine.

I completely misinterpreted this and though the machine was supposed to come with a set of gears to cut metric threads. The machine has an 8TPI lead screw and I was mistaken in thinking it should have come with a set of gears to adapt the English lead screw to cut certain metric threads. (rookie mistake)

the mystery is solved! and I am content knowing the machine I purchased is a complete unit. Lots of good came out of this post. The YouTube video shared to this thread was especially helpful in wrapping my head around how change gears interface with actual thread cutting.


----------



## B2 (Oct 30, 2021)

Great!  Glad I could help.  So someday when you really need to do a specific metric thread you can buy a few change gears that will get you a close approximation to the metric you want to make. Even a poor approximation will fit over a certain number of threads (length and looseness of the engaged thread plus the approximation error determines if they will fit.   Or you can purchase a small set and get close to a lot of the standard metric threads.  I have even been known, when in a pinch, to make a loose English TPI that is a close approximation to the metric thread that I need.  If it is not a load bearing issue then you can just cut a few threads so that only a "few threads" are engaged and the two parts will turn together.  Not a great solution, but when in a pinch you can make a "pinch" fit a little bit.   I.e.  We have all tried to put a metric bolt into an English nut of similar size before we notice the difference.  They go in a little before binding!  So "few threads" are defined! --- not what we would call "fine" or "high quality" machining.

It is a bit interesting to think about the loads on the threads and the desired material properties.  If the two parts threads do not match then how is the load on the threads distributed?  Even, if they are designed and made to match they will not be exact, so which threads bear the load.  Important question: How flexible is the material of the threads?  I.e. as they are loaded do they bend a little so that the next thread also engages? Is it linear and so recovers when undone.   So does this not mean that that a strong, but spring like material would also be the strongest bolts.  Steels are pretty much what springs are made from.  The atomic bonds stretch before the atoms slip in position.  So they are elastic, where as copper do not make good springs nor strong threads... It is soft, so that the atoms, especially at the grain boundaries, slip around rather than the atomic bonds stretching. On the other hand soft copper can sort of be mashed into shapes before it breaks.   Ceramics are very hard an brittle.  Poor elastic properties.  Not good springs nor bolts.  It is all about the elastic limit.  Don't exceed it and a spring will come back to its original shape.  

Dave


----------



## B2 (Oct 30, 2021)

PS.  All the more reason to have an electronic lead screw (ELS).  Then you can drive the approximation to nearly accurate.  See You Tube by Clough42 "Lathe Electronic Leadscrew"


----------

