Re: [CAD_CAM_EDM_DRO] Re: New Mini mill/drill

Klaus,

Thanks for the information. I've always wandered about how these
machine mail order catalogs get and sell these machines. I've talked to
a fellow some time ago, he was convinced that the machines were sold on
a grade bases. Something about a machine made it better, maybe the
quality of the castings, machining or better design feature. The better
machine he thought were sold to the "flashy" catalogs like Grizzly and
the "rot gut" got sold through Harbor Freight. Is any of this true? I
think the Harbor Freight version if it does have a R8 spindle would be
the preferred, if all else is equal. Though your insight on the
machines being still on the high sea does cause me to wander if Grizzly
would be better. I've bought a lot of stuff through Harbor and have
mostly been satisfied. Though once I did encounter the "vaporware",
ordered the 3 in one sheet metal machine. After about 2 - 3 months
waiting I canceled and ordered the same machine from Grizzly, got it in
about a week. Did cost a bit more due to shipping.

Edward Rupp

klaus@... wrote:

>
> Hi Edward,
> I own the Grizzly mini-mill and can answer some of your questions.
> The mill has a #3 Morse taper and comes with one 3/8" and one 1/2"
> collet that uses an also provided M12 drawbar. I prefer using end
> mill holders with 3'8-16 thread for which I made my own drawbar.
> Don't worry about the toolholders falling out. As a matter of fact
> most people have problems getting them out when they are changing
> tools, because they tightened the drawbar with a wrench instead of
> just hand tightening it. I would never use a Morse taper without a
> drawbar in a mill, though.
> The Harbor freight mini-mill is practically identical, but uses R8
> tooling. The JT33 that is mentioned is just an R8 to JT33 arbor for
> the drill chuck. R8 holders are a little easier to get, but that
> doesn't mean that you would be happy with a 3" boring head on one of
> these little mills. As far as I know the Harbor Freight mini-mills
> are still on the boat. Nobody has actually received one, yet.
> Potential for CNC conversion: X and Y are pretty easy. I've started
> on the X drive using a servo motor with a 16:1 double belt reduction
> and the stock acme screw. Gives plenty of torque and enough speed,
> 16IPM, considering the small working envelope of the machine. I
> bought the Geckodrive 320 servo motor driver to use with it.
> The Z-axis is a different story, as it uses a rack and pinion drive
> which would have to be replaced. Since that makes it less usefull as
> a drill I will probably stick with a 2D system and would not
> recommend these mills if you want to do engraving.
> Klaus
>
> --- In CAD_CAM_EDM_DRO@y..., Edward Rupp <edwardrupp@n...> wrote:
> > Hi folks,
> >
> > I've been looking at a new mini mill/drill machine that Harbor
> Freight
> > (item 44991-0ARA) and Grizzly (G8689) are selling. It looks like a
> > great candidate for a CNC conversion. Has any one had experience
> with
> > this model?
> >
> > The machine looks identacl from both mail order catalogs. However
> > Harbor Freight clams their machine has a R8 taper spindle, and
> > confusedly says it comes with a JT33 chuck taper. The Grizzly
> catalog
> > says only a M3 taper.
> > I'm wary of using a morse taper for milling. In my drill press the
> > chuck is held in by probity a M3 taper. It falls out if I have a
> drill
> > chatter or the drill sticks in the work. Seems to me a mill with a
> > morse taper would be worthless.
> >
> > Any thought on the spindle suitability?
> >
> >
> >
> > Thanks a bunch.
> >
> > Edward Rupp
>
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