Screw cutting by hand

Hi All

Being a modelmaker there is always a need to screw-cut fine threads and these can be fiddly underpower of the lathe especially up to a shoulder.. To overcome this, cutting by hand gives me a little more control and feel while cutting the thread.

The lathe gear train is set to cut the required TPI or pitch, the leadscrew can then be engaged. In the back of the chuck spindle a crank handle is locked to to place to rotate the chuck/collet.

The photos below show the set up for cutting a piece of 3/16" phosphor bronze 5" long 3/16x40TPI. To support the bar a rotating centre in conjunction with a travelling steady was used. The crank handle is then rotated by hand and with the saddle engage onto the leadscrew to cut the thread in the normal way.

The lathe spindle drive belt is also disconnected for two reasons. Firstly to make the rotation of the spindle easier and secondly to prevent myself from starting the lathe and having the crank handle spin around dangerously.

Attachment 38990Gear train to cut 40TPI

Attachment 38988Spindle handle. This is a commercially made handle by Myford.

Attachment 38989Centre and travelling steady supporting the 3/16" diameter bar being cut

Many thanks
The Home Engineer

Never cut such fine threads this would occur, but certainly hand spun to get large radii on parts with form tools.

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Thanks thehomeengineer! We've added your Manual Screw Cutting Method to our Machining category,
as well as to your builder page: thehomeengineer's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/homemade-manual-screw-cutting-method"> <img src="/uploads/248382/homemade-manual-screw-cutting-method.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/homemade-manual-screw-cutting-method">Manual Screw Cutting Method</a> <span> by <a href="https://www.homemadetools.net/builder/thehomeengineer">thehomeengineer</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/lathe'>lathe</a>, <a href='https://www.homemadetools.net/tag/cutting'>cutting</a> </div> </div> </div> </div>
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