[modeleng] Re: Screwcutting
- From: Patrick Coppens <develop@xxxxxxxxx>
- To: modeleng@xxxxxxxxxxxxx
- Date: Sat, 24 Nov 2007 13:19:51 +0100
Shep wrote:
> Hi Ron
>
> In the little lathe I am building from scratch, I deliberately planned the
> leadscrew engagement lever on the left (as in Myford). My reasons are that
> you are using the saddle hand wheel much more than the screwcutting lever -
> so that the incidence of hot swarf is proportionately greater when plain
> turning with the handwheel, than with screwcutting. You pays your money
> and you make your choice!
>
> On the Emco 10 lathe, which I had before I got the Hardinge (which has a
> very nifty screwcutting system) I used to reverse the lathe, rather than
> disengage the leadscrew after each screwcutting pass. I made a very
> simple slide, which stopped the cross-slide at the exact previous setting,
> after withdrawing, reversing and resetting. I had a micrometer barrel
> acting against this, with a ratchet with 'thou' clicks. On resetting, a
> few clicks and you were ready for the next cut - if you see what I mean.
> This was far simpler to make, than a retracting device.
> I may have a pic of this somewhere, if anyone is interested.
>
> This system of reversing, instead of disengaging, obviates any problems
> with, for instance, cutting metric threads on an Imperial machine; and
> solves the hot swarf problem!
>
> Cheers! Hubert
>
>
>
> ----- Original Message -----
> From: "Ron Head" <ron.head@xxxxxxxxxxxxx>
> To: <modeleng@xxxxxxxxxxxxx>
> Sent: Saturday, November 24, 2007 11:49 AM
> Subject: [modeleng] Re: Screwcutting
>
>
>
>> Hi Patrick
>>
>> The retractable toolholder is a nifty device, but the only benefit seems
>> to
>> be that you don't have to remember the tool setting at each pass. You
>> still
>> have to be quick to disengage the leadscrew at the end of the cut.
>>
>> When I'm screwcutting, I like to make an undercut at the end of the
>> thread,
>> for the tool to run into. I also run the lathe at a fairly slow speed, to
>> give me sufficient reaction time!
>>
>> Which brings me onto one of my big grumbles with the Myford lathe. The
>> leadscrew engagement lever is on the left of the saddle, which means that
>> when you are holding the lever and getting ready to disengage, you have to
>> put up with hot swarf bouncing off the back of your hand! Why they
>> couldn't
>> put it on the right, I'll never know.
>>
>> Regards
>> Ron
>>
>>
>>
>
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>
Hubert,
If you have any pics going, I am interested, as I still have to
"finalize" my screw cutting setup, in the small C1!
Cheers
Patrick
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