[modeleng] Re: Screwcutting
- From: "Shep" <shep.28@xxxxxxxxxxxx>
- To: <modeleng@xxxxxxxxxxxxx>
- Date: Sat, 24 Nov 2007 12:15:08 -0000
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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