[mmukhaizeem]

Hello everyone, I recently bought an RF45 clone mill/drill machine and I am in the process of converting it to CNC.

I have disassembled the machine and in the process of lapping its ways, I also opened the gear box to clean it up and change the oil. Also planning on replacing the bearings before putting it back together.

My thoughts are to replace the spindle with a 30 tapered (just ordered) and convert it to belt drive.

I would like to be able to mill stainless steel as well as aluminum, I know I need rpm range from 100 to 5000 in order to have nice finish on both.

so my question is what type of motor/pulleys and VFD or (a gear mod) I should use to maintain high torque at low speeds?

I have no clue when it gets to motors and any help would be highly appreciated.

thank you.

[Fastest1]

Isnt it an R8 spindle?

[mmukhaizeem]

Its an MT4 spindle

[mmukhaizeem]

Is it possible to modify the gear box and use the stock motor (3 phase 1400rpm) and get 100 to 5000+ rpm range? Maybe using a VFD with that as well?

[gd.marsh]

You can use the stock motor with a compatible sized VFD (2 or 3hp). To do the typical belt drive conversion most guys make new mounts to put the motor pulley on top of the head cover rather than inside the head. I think I have seen one thread where a guy put the belts & pulleys inside the head, but it's not the most common way.
To get higher RPM & lots of torque at low RPM .. you'll have to go with 2 step pulleys (like 1:2 / 2:1 or similar) these might be able to be purchased but I think most guys make their own which means you need a lathe that can effectively cut 5" or 6" diam.
My thread is pretty long, but somewhere back towards the beginning is where I document the belt drive conversion I did that gave me up to 8,000 RPM by running the VFD @ 130Hz ..

Do a search for 'Bolton ZX45 Conversion' on the Zone..

[mmukhaizeem]

You can use the stock motor with a compatible sized VFD (2 or 3hp). To do the typical belt drive conversion most guys make new mounts to put the motor pulley on top of the head cover rather than inside the head. I think I have seen one thread where a guy put the belts & pulleys inside the head, but it's not the most common way.
To get higher RPM & lots of torque at low RPM .. you'll have to go with 2 step pulleys (like 1:2 / 2:1 or similar) these might be able to be purchased but I think most guys make their own which means you need a lathe that can effectively cut 5" or 6" diam.
My thread is pretty long, but somewhere back towards the beginning is where I document the belt drive conversion I did that gave me up to 8,000 RPM by running the VFD @ 130Hz ..

Do a search for 'Bolton ZX45 Conversion' on the Zone..

gd, thank for the reply.

I have been reading your post for the ZX45 and I like what you did, very nice setup.

Can you tap holes at 270rpm? how is the torque at that speed? is it enough to machine some stainless steel ?

Thanks

[dracozny]

gd, thank for the reply.

I have been reading your post for the ZX45 and I like what you did, very nice setup.

Can you tap holes at 270rpm? how is the torque at that speed? is it enough to machine some stainless steel ?

Thanks

I have manually done stainless steel on my zx45. It is very tricky to work with, as in getting it to cut at the right speeds without inducing a ton of chatter.

[SCzEngrgGroup]

You can use the stock motor with a compatible sized VFD (2 or 3hp).

Isn't the stock motor a single-phase AC motor? If so, it can't be used with a VFD. If it is, it must already be running on a VFD.

Regards,
Ray L.

[mmukhaizeem]

I have manually done stainless steel on my zx45. It is very tricky to work with, as in getting it to cut at the right speeds without inducing a ton of chatter.

well if that conversion has the torque to machine SS they I will be happy. I plan to fill the casting with epoxy/sand, and also do have an old cast iron safe with 30mm wall and that will be my mill stand, it weighs no less than that mill it self. I hope that will reduce that chattering to the minimum

I am really slow at getting things done but I will try to keep this post updated

Thanks

[mmukhaizeem]

Isn't the stock motor a single-phase AC motor? If so, it can't be used with a VFD. If it is, it must already be running on a VFD.

Regards,
Ray L.

It is a 3 phase motor 460v with no VFD. we just use 220v 50Hz for single phase and 460 50Hz for 3 phase.

Thanks

[mmukhaizeem]

Sorry I mentioned 3 phase is 4 60. Well it is a 380v!

[Uguessedit]

Is it possible to modify the gear box and use the stock motor (3 phase 1400rpm) and get 100 to 5000+ rpm range? Maybe using a VFD with that as well?

Yes if it needs to be modified. If it helps a PM833-t uses all metal gears and will spin 8000rpm with a remote installed cooler with fan and a oil pump. We have one of ours running the gearbox with same setting and other than combatting oil heat no issues. Also used synchromesh manual transmission fluid which is safe on the bronze. It runs around 110 degrees on a hot day continually with pump and cooler.