Re: [CAD_CAM_EDM_DRO] Re: Shopbot, Rack and Pinion, Ball Screw, Acme precision screw?

On Sat, 26 Apr 2003 17:19:27 -0000, you wrote:

>Hi Wes,
>
>I haven't seen the figures for the backlash on the gearheads. I have
>a data sheet (?) in my gearhead boxes, but no help there.

OK, the gearheads I have on motors (already) are 2GK18KA, and I was
looking for specs on them, ratio and maximum torque.

>
>I was thinking of using these motors/gearheads on something like a
>router. I also haven't seen the spec's on the ShopBots, where I
>believe similar motors/GHs are used. That's where I thought you were
>contimplating using them.

Wes wants the shopbot, I think, and I want to put this on the Z axis
of the Grizz..

>
>Could be OK for your Grizz, but why not just use a appropritately
>sized stepper at 1:1 or perhaps 2:1 to drive the axis?

I only have so many steppers, and will be using most, if not all of
them. The ones I have are a bit light for the Grizzly, 150 or so
in-oz, most people recommend 200 to 300. The z axis is normally
driven with an add-on acme lead screw, and most people use 300 to 400
in-oz steppers for that.

However, the PH266 motors with the 2GK gearboxes were very low cost,
do work, and I was thinking of putting that on the fine feed. You pop
in a handwheel to couple to the fine feed, then pull it out to go
manual. I like the idea of manual/automatic modes. The package would
be a convenient mount for me as well.

For the rest of it, the Grizzly is a bit down the road, so I don't
want to go buying parts for it too soon... Lots of Hamfests coming
up, I hope.

The L297/298 board I just put together works very well with the Fuji
(150 or so in-oz) unipolar stepper run in bipolar mode (half the
winding). That goes on another project as well as going on several
other stepper projects.

It's possible I will use the PH266 motors on something else, but I'd
like to see what the torque was rated for. I suspect that the gear
ratio was 18:1, which means that the 76 or so in-oz I could get from
the stepper should be at least 10 times higher, I'd think. However, I
was worried about exceeding the ratings of the gearbox.

Harvey

>
>Alan KM6VV
>
>
>--- In CAD_CAM_EDM_DRO@yahoogroups.com, Harvey White <madyn@i...>
>wrote:
>> On Fri, 25 Apr 2003 13:07:29 -0700, you wrote:
>>
>> >Hi Wes,
>> >
>> >I'd watch the surplus and ebay channels for Oriental Motors (Vexta)
>> >stepper/gearhead motors. I recall seeing ShopBot pix, and the
>> >motors/gearheads looked like ones I've picked up. PH266 motors,
>> >2GK7.5KA gearheads. Makes me want to build a router if I can use
>my
>> >parts!
>>
>> I've looked for the specs on the gearheads. I've got several
>> PH66-01GK Vexta steppers with 2GK18KA gearheads. I've managed to
>> crossreference the motors, and found the specs on the motors (I
>> think), but the gearheads remain unavailable, spec wise...
>>
>> Any pointers?
>>
>> I'm thinking of driving the fine feed on a Grizzly Mini-mill with
>one,
>> I've got a Z axis DRO, so I'm less worried about backlash than
>> otherwise.
>>
>> Harvey
>>
>>
>> >
>> >Alan KM6VV
>
>