Re: [CAD_CAM_EDM_DRO] Gorton mill

Jeff Barlow wrote:

> Hi Ron,
>
> I am indeed a "Home Shop type, looking for a nice machine,
> cheap". I'm also an EE, computer type guy more than a
> machinist. My only formal machine shop training was in high
> school, a loooong time ago. So, I'm in over my head already,
> just trying to figure out if I want to lug this thing home.
>
> If there wasn't twenty odd miles of the Pacific Ocean
> between where the mill and I am now and my shop on the
> mainland, I'd just haul it home first and then figure out
> how much trouble I was in. However, I don't really want to
> pay about $300 to the barge operator to move 2500lbs of what
> may turn out to be scrap iron.
>
> If I were to take this huge thing, my plan would be to pull
> it apart, clean it up, and rebuild it as a CNC mill. This
> means throwing money at it for ballscrews, etc. etc. So this
> "free for the taking mill" would cost a bit of dough, after
> all. My fear is that by the time I found and paid for the
> oddball tooling it needs, I'd have sunk so much time and
> money into it that I might as well have bought a clean used
> Bridgeport.
>
> You say "Making a tool holder should not be beyond the
> ability of any HSM guy." Well it seems beyond mine right
> now. My abilities have been known to improve with time,
> though. If someone here would care to try to educate me
> about this, I'm sure ready to listen. The idea of just
> making a new spindle occurred to me, but I'm a bit too
> ignorant to know if that's a silly idea or not.
>
> I'll be here, within walking distance of the mill through
> this weekend, and I'll be back here next month sometime,
> and, of course, the mill isn't going anywhere. I'll have
> plenty of time to change my mind about this dozens of times.
>
> Thanks,
> Jeff
>
> On Wed, 23 Aug 2000 08:38:44 -0400, Ron Ginger wrote:
>
> >I may have a different view of this- I think the original poster was a
> >Home Shop type, looking for a nice machine, cheap. In that case I say
> >grab this mill. Its clearly an 'industrial quality' machine, likely a
> >much better base to start with than a chineese import.
> >
> >The major problem seems to be the lack of tooling for the spindle. Well,
> >for a HSM guy,just how many tool holders do you need? If you can
> >find/buy/make just one holder to hold a 1/2" shank end mill you have a
> >very usefull machine.
> >
> >Making a tool holder should not be beyond the ability of any HSM guy. A
> >comercial holder wold likely be a wonderfull, hardened, ground, device.
> >A home made holder of common cold rolled steel, nicely machined, but
> >maybe with less than perfect surface finsih will work fine- it might
> >wear faster than a properly ground holder, but come on guys, how many
> >HSMers will live long enough to wear a tool holder- and if you did, by
> >then you would be so much more expierenced you could make a better one.
> >
> >A 'free for the taking' mill is worth it!
> >
> >ron
>

I understand your reluctance to invest in possible scrap iron. However, EE's tend to be bright and often stubborn people that
tackle difficult projects and make them work. No I'm not a EE I just grew up with one!

I just did a new spindle for my big mill. I still have to grind and lap the taper but prelim results seem to be OK.
The spindle is a 40 NTMB with an opposed pair of angular contact on the rear (50 mm) and a tapered roller ( 3.2500" for the front
bearing. So it can be done. I used 1045 and heat-treated. I would change a few things if I ever do it again, like use 4150 Q&T.

Aside from this: Is the Gorton stiff enough to make a significantly better mill if you fix it? IMO you can go to a lot of trouble
to get stiffness if you are going to mill steel. Not to start a war here but BP's are really nice for Al but I would prefer
something stiffer for steel. That doesn't mean that a lot of good stuff has not been done on the small BP's. It just takes longer
to hog steel and get a nice final pass.

Dave

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