Re: [CAD_CAM_EDM_DRO] re:Lathe Rack & pinion.

I presume when you install the ball screw you disconnect the lead screw and
the feed screw? With all three connected, I would presume it would be
pretty difficult to drive the carriage back and forth with any
screw.....sort of like having THREE gears all meshed together at once.

Yes, laugh at thethree gear mesh if you like, but I actually saw a gear
train that was designed that way once. I was checking the job and sent it
back for a redesign.

Smoke



-----Original Message-----
From: diazden <diazden@...>
To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
Date: Sunday, November 12, 2000 4:01 AM
Subject: Re: [CAD_CAM_EDM_DRO] re:Lathe Rack & pinion.

>Chris;
>why don you put the ball screw on the other side of the carriage?
>you could fix the bearings on a couple of clamps at the very beginning and

at

>the very end of the bed ,that way you will have a manual machine as well

and

>the lathe wont have to be modified
>regards
>mariano
>
>
>Chris Hellyar wrote:
>
>> OK, This is a bit larger than a taig though...
>>
>> I'm actually going to be up against this question myself sooner or later.
>> I've got a new lathe (brand new and shiny) in the garage now, which I've
>> bought to make the parts for my router.. This may seem a little over the
>> top, but I did have access to a lathe at a friends place, but he's moved,
>> and it's 50k's to the next nearest lathe I can use... Too much hassle,

and

>> it was a good excuse to buy a larger lathe than my wee "cnc" job.
>>
>> But I digress...
>>
>> The cross on the lathe will be fine to convert, very conventional

threaded

>> rod into a split brass or similar material nut which is "pressed" to take
>> out the backlash. For that axis we can just put a toothed pulley on the

end

>> of the screw and away we go....
>>
>> The carrige however has a huge lump of mechanisim on the apron which

means a

>> second leadscrew is out, and the existing one is captive at both ends in

the

>> castings by some magic method of assembly. Without major work I can't

see

>> how to get a backlash free drive onto the screw. Not to mention the fact
>> that the threading leadscrew is a typical interrupted acme thread job for
>> driving the powerfeed, and the split nut has heaps of friction so

probably

>> wouldn't do the job too well.
>>
>> I think if I did mine I'd just rip out the leadscrew and most of the

apron

>> mechanism and put a new acme screw in there, but on the lathe I looked at
>> the owner wants to keep all of the manual functionality.
>>
>> Cheers, Chris.
>>
>> * Design engineer, Assembly worker, Cleaner.
>> * Ohmark Electronics. PO Box 5302, Christchurch, New Zealand.
>> * http://www.ohmark.co.nz
>>
>> ----- Original Message -----
>> From: <ballendo@...>
>> To: <CAD_CAM_EDM_DRO@egroups.com>
>> Sent: Sunday, November 12, 2000 1:09 AM
>> Subject: [CAD_CAM_EDM_DRO] re:Lathe Rack & pinion.
>>
>> > Chris,
>> >
>> > I've seen a Taig lathe CNC retrofit that used the rack. The stock
>> > taig HAS NO leadscrew. Sorry, I don't remember exactly where, it was
>> > on the WEB, and recently... Prob'ly bookmarked it, but I'm
>> > using "borrowed computer(s) just now.
>> >
>> > Hope this helps.
>> >
>> > Ballendo
>> >
>> > P.S. Call Taig and ask. The CNC stuff is done by the son. Different
>> > co. name. The first Taig CNC lathe(by Taig) was the son's. When I
>> > heard about it several years ago, I called and asked him how it
>> > worked with the Rack drive. He said, "My Dad put in a leadscrew for
>> > me"!!
>> >
>> >
>> > > Anyone had any experience doing a retrofit to a lathe and used the
>> > >Rack & pinion drive on the lathe apron instead of the lead screw?
>> > >I've just looked at a lathe a friend is considering retrofitting
>> > >after seeing my wee lathe,<snip>
>> >
>> >
>> >
>> >
>> > Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
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>> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the

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>
>
>Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the

discussion of shop built systems, for CAD, CAM, EDM, and DRO.

>
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