# Z axis motorisation GO704 mill (Optimum BF-20LV)



## deeferdog (Feb 1, 2017)

Hello to all. I have been asked to post some pics of the Z axis mods I have don to my mill. This machine is marketed in Australia as an Optimum BF-20LV, In the US I think it is a Grizzly GO704. It is a Chinese machine, I like it a lot and would recommend it to anyone. One thing that bugged me was the location of the Z axis feed wheel, top right hand side. This revealed two things about the designer, he was taller than me and not as lazy. These have been motorised before, as a quick search of the internet will reveal, however most of those that I could find were done by people who were modifying the machine for CNC and their requirements are a lot different to mine, I just wanted the thing to go up and down without all the effort.
As luck would have it I acquired a small Chinese scroll saw for $50. These are sold by a grocery chain in Australia (Aldi) and this was marked down. Although I didn't need a scroll saw, I knew how good they were from a friend, especially the speed control. If you dismantle the machine you will end up with a very good motor and speed control, contactor (Off/On switch), fuse and all the wiring.
These mills are easy to modify as the Z axis lead screw is accessible at the top of the column. The pictures tell the story, I machined and fitted a pulley to the leadscrew, mounted the motor with a pulley 1/3rd the diameter of the other, put all the wiring in a suitable enclosure and mounted that to the side of the mill. To assist the motor with the load, I installed a gas strut to the side of the column. I have no idea of its specifications, I purchased it from the auto barn because it was the right length. It made a big difference because the mill head very heavy. The original Z axis hand wheel was removed and knurled on its rim and the handle removed. This is the fine adjustment to the quill.
The system works well, speed control on the motor is so fine I can use it as a power feed for boring and drilling. Rapid up is fast, about 5 secs from lowest position. A limit switch on the up stroke stops the head at the top position. In productivity alone it is a great leap forward but the biggest advantage not having to crank that wheel!

P.S. I'm ashamed of the pictures, the top one is correct as is the second one looking down on the installation. All the others need to be rotated to the right. I have spent longer trying to do this than the mill conversion took!
Regards,
Peter


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## ShopShoe (Feb 2, 2017)

Thank you for posting that.

---ShopShoe


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## Wizard69 (Feb 3, 2017)

Nice!

As they say, there is more than one way to skin a cat!


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