Buying a Grizzly G9729 mill/lathe. Have some questions.

[Rceagle1a]

I found a Grizzly G9729 on marketplace. I have questions about it. Can mods be made to let it go down to 0.5mm thread pitch? Grizzly says no but I'm guessing it could be possible. Hope to not be a pest about learning how to run this machine.

 

[Reddinr]

It looks like you would need to make a custom gear set. 0.5 is 50.8 TPI. There are selections for 48 and 54 TPI, which would be 0.53mm or 0.47mm if I did the math right. About 6% off or 0.03mm/turn. There is a 1mm setting, I guess with the custom right gear arrangement you could cut that in half to make 0.5mm possible.

BTW, since this is an "inch" lathe, you won't be able to use the half-nut (thread dial) for most metric threading.

 

[matthewsx]

Search "Electronic Lead Screw"

 

[markba633csi]

Thread dial. Won't be able to use the thread dial, half nut yes, for metric threading
I would reconsider buying that combo machine- it's not convenient having the mill head hanging over the lathe headstock like that.
The machines that have the mill portion bolted to the rear of the bed are a much better choice- as far as 3 in 1s go
And overall it's much better to have two separate machines, even if they are small. Changing setups between lathe and mill is a true pain
We try to steer folks away from the combo machines because of their many limitations and poor resale value

 

[Rceagle1a]

Thread dial. Won't be able to use the thread dial, half nut yes, for metric threading
I would reconsider buying that combo machine- it's not convenient having the mill head hanging over the lathe headstock like that.
The machines that have the mill portion bolted to the rear of the bed are a much better choice- as far as 3 in 1s go
And overall it's much better to have two separate machines, even if they are small. Changing setups between lathe and mill is a true pain
We try to steer folks away from the combo machines because of their many limitations and poor resale value

Unfortunately, I'm committed to buying this machine now. I'll research modifications to get the threading ability down to what I need(0.5mm).

 

[RJSakowski]

Looking at the manual, replacing the 24t gear on the lead screw gear box input shaft with the supplied 48t gear will allow you the thread .5mm threads. There may be an issue with clearances though. (Fig 52 in the manual.)

Edit: I looked at the manual again. The 48t gear is used for position A for cutting a 1mm thread so you would need a second 48t. gear.

 

[matthewsx]

Hope you’re not paying too much. My first machine tool was a combo and I was happy to sell it for less than half what I paid.

A determined machinist can do good work with anything given time. But, since you already have requirements in mind it would be best to get something that meets those rather than modifying something that doesn’t.

If the Grizzly is cheap enough maybe flip it and get something that’ll work for you.

We all go down rabbit holes, just try to make sure they are more interesting than frustrating.

John

 

[Rceagle1a]

Looking at the manual, replacing the 24t gear on the lead screw gear box input shaft with the supplied 48t gear will allow you the thread .5mm threads. There may be an issue with clearances though. (Fig 52 in the manual.)

Edit: I looked at the manual again. The 48t gear is used for position A for cutting a 1mm thread so you would need a second 48t. gear.

I appreciate your response. I look forward to getting this machine and learning how to run it.