# 9x20 lathe feed gear



## Rise Of The Curtain (Jan 15, 2020)

So I’ve got a Central Machinery 9x20. I know its far from a quality machine, but it’s my first lathe, and I’m enjoying myself.The problem I have is the auto feed. Forgive me if my terminology is incorrect.... The worm gear that meshes with the lead screw seems to be just fine, it‘s the worm wheel that meshes with that, that causes the feed to bind. I cannot find a source for this gear anywhere. I hear that the Grizzly G4000 is the same, but exactly the same? Any help would be appreciated. Also, the v-belt, is it 710mm or 730mm? Thanks everyone. 

J


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## DavidR8 (Jan 15, 2020)

Do you mean that it binds when you’re hand feeding the carriage?

Edit: one more thing: what machine you have does not matter here. What matters is that you’re having fun and learning 

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## Rise Of The Curtain (Jan 15, 2020)

DavidR8, I like the attitude. There’s such a stigma around these machines, but clearly they serve a purpose.

It binds in power feed only. I‘ve torn into the apron and can see physical damage to the worm wheel. The peaks of the gear teeth vary around 60 thou. The teeth are also forming ridges across the thickness of the gear, as if it was just slightly the wrong gear. I should have taken photos then, but I will tear it apart when I get home, and upload some photos. Thanks for the reply.


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## Dudemanrod (Jan 15, 2020)

Count the teeth and diameter of the gear. Call Grizzly tell them the G4000 may have the same gear and they will check it out for you. Alot of parts interchange but not all you may have to modify it a little. Look on there sites parts maual for the 4000


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## savarin (Jan 15, 2020)

On my 9x20 (see, your not the only one) the worm could slide along the gap in the bracket around 1/16 which allowed the key to jam.
Read this thread to see what I did and in particular the very last post that I found absolutely vital.
They are a good little lathe when you get all the bits fitting correctly.


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## C-Bag (Jan 15, 2020)

savarin said:


> On my 9x20 (see, your not the only one) the worm could slide along the gap in the bracket around 1/16 which allowed the key to jam.
> Read this thread to see what I did and in particular the very last post that I found absolutely vital.
> They are a good little lathe when you get all the bits fitting correctly.


Savarin is da man about the 9x20. Thing is, I think you meant to link to your article and I don't see it.

I also own a HF 9x20 that the threading half nut was not adjusted right and was mangled. I bought a new half nut from Grizzly and it fit perfect. You might want to DL the manual for the 4000 and check it out as it speeds stuff along if you can refer to it as it gives the part name. It helps us help you. Not trying to be a snob, just been there and struggled with the same thing.


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## savarin (Jan 15, 2020)

oops!








						9x20 stuffup
					

I'm unsure if it was my fault or the machine. I had two aluminium flanges bolted together on the faceplate with spacers so I could turn the outside dia and bore the inside dia parallel with each other and both end up exactly the same. All was going well on slow auto feed - bore, disengage the...




					www.hobby-machinist.com
				



This was done shortly after I purchased the lathe and also started to learn how to use it.
I would use a bronze if I have to do it again.
Heres something else that may be worth looking in to








						Stripped Half Nuts
					

well, not both halves. I cleaned the lathe the other day and made some adjustments oiled etc. When running the lead screw from the tail stock to the head stock with the half nuts closed as if threading I noticed the carriage stopped  moving about half way along. It looked as if the half nuts had...




					www.hobby-machinist.com


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## savarin (Jan 15, 2020)

That little V belt could be either, if the old one is broken then measure it and see how close to either measurement.
The larger will work for some speeds but not all as I found out by mistake.
I use the 710 purchased from pets palace in the states, or at least I used to but their overseas postage is now outlandish and costs more that the product.


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## Rise Of The Curtain (Jan 16, 2020)

savarin said:


> oops!
> 
> 
> 
> ...



So I looked up the Grizzly G4000 and it looks like part number p4000739 is my best bet. Thanks for all the input from everyone. All the keys were accounted for, but that doesn’t mean they didn’t cause the damage before I purchased it. I’ve only had it for two weeks, I’m sure I’ll find more to repair. I am attaching a few photos for reference.


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## Araitim (Feb 4, 2020)

I am also having an issue with my auto feed. It will move the tool post 1 full turn then start popping. Some times I can turn the wheel a bit by hand again and it would catch and continue for another turn. Were you able to find exact parts? I believe mine is a Central Machinery/Lincoln 1240g9/1440g9. I have yet to take it apart but the fact that it happens in the same position seems to point to a gear.


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## Dudemanrod (Feb 4, 2020)

Looks like the carriage has to come off so you can do a proper diagnosis. I'm sure you can find a suitable part. The gear that the worm turns seems like it gets alot of use you may be able to see it with a flashlight right behind the apron.


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## vocatexas (Feb 4, 2020)

On my CM 9x20 I use both size belts. One is too tight on some speeds and the other is too loose on other speeds. I think I paid less than ten dollars each for the belts at my local NAPA parts store.


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## Rise Of The Curtain (Feb 4, 2020)

I ended up using the 710mm belt. So far so good. As far as the feed gear, I ordered the grizzly replacement for the G4000. I have yet to receive it but when I do I will post the results. Has anyone considered a 3d printed feed gear? I mean, if your carriage is maintained well and adjusted to work smoothly, why wouldn’t it work? I can’t find anything on the web related to the CM 9x20 feed gear, so maybe I’ll model the new gear when I get it. Obviously I can’t really model the old gear as it’s probably more than a millimeter out on the radius....


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## Dudemanrod (Feb 4, 2020)

I think that a plastic gear would be fine. I have an 80 tooth gear on one of my back gears. I tried to get one and never succeeded. There are online retailers that sell gears but they didn't have what i needed. A 3d printer would solve alot of those kinds of problems.


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## Araitim (Feb 5, 2020)

Dudemanrod said:


> Looks like the carriage has to come off so you can do a proper diagnosis. I'm sure you can find a suitable part. The gear that the worm turns seems like it gets alot of use you may be able to see it with a flashlight right behind the apron.



It looks like you are 100% correct. That gear is worn out. Now to try and find a replacement. It's a 20tooth. Its damn near impossible to find info on my specific machine which is why I jumped on this thread, it seems to be the same machine as mine.


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## DavidR8 (Feb 5, 2020)

I have no connection to this place but if all else fails this could be an option.




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						Any Gear Made Quickly Inexpensively & Perfectly Al Meekins GearsMade.com. --Delrin gears Plastic gears Bevel gears Worm gears Spur gears Helical gears Phenolic gears Stainless steel gears Cast iron gears Machine gears Steel gears Metric gears Bronze 
					





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## Dudemanrod (Feb 5, 2020)

Go grizzly.com and look up the 14x40 lathe and check out the parts illustrations. And see if that looks similar. It's real close might have to call them and see what the tooth count is.


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