Shear Tool

I made one some years ago for the sole purpose of making a steel between centres test bar (dumbbell type with two raised bands) for setting the tailstock on centre as I didn't have access to suitable grinding equipment. The finish on the bands still looks polished. I haven't used the tool again.

Martin C

Looks like it could be useful tool in the armoury. For a relative newcomer, could someone post a picture of one please. Googling "shear tool" was hopeless.

The shear tool works really well on a shaping machine for finishing cuts.

You can see the shape of the tool and how it works here.

https://www.youtube.com/watch?v=-CWGScRNXfw

Phil

Edited By Phil P on 25/10/2020 13:48:16

Hi Guys,

For those of you that saw my fly cutter, I've used "Shear tool" bits in that and you can easily get glass like finishes with it. The idea came about in the early 1900's for use with shapers to get a smooth finish. Bear in mind that in those days they only had carbon steel tools, so getting a fine finish wasn't easy.

Edited to add fly cutter picture.

Edited By John Baron on 25/10/2020 14:55:10

Here is the setting tool I made some time back and the shear bit I made to make it. In use somewhere along the cutting edge is used, not a corner. The top picture shows how the tool is presented to the workpiece, very slow power feed is used.

Martin C

Hi Bo'sun, try searching for "shear tool for lathe"

Regards Nick.

The simplest way to make one is similar to a flat-ended d-bit. Grind a step on a length of round HSS to half diameter, grind relief behind the cutting edge.

Fitted in a simple round holder (e.g. a boring bar holder) with the mid point approximately at centre height, you just rotate the tool for the most effective result. Ideally you are taking cuts of a thou or less.

Neil

Thank you, it's quite obvious once you've seen one in action.

Sounds like using a square toolbit, with the end ground at an angle, and mounted so that it is below centre height would do the job?

Must give it a try!

Howard

The edge needs to cross the work at a fairly steep angle. If it's vertical the contact point is automatically at centre height.

Neil

Have a look here..

**LINK**

I made one last year based on the above; works nice giving a fine finish in trials. I'll take a pic of mine later & post.

George.

Re. my previous post ...My shear tool...

Only used on trial DoC .001-2" haven't got pic of 'angel hair' cuttings, will arrange something later although there are plenty on YouTube.No need for centre height setting as cutting edge tangential to work & can be adjusted up/down to suit as edge wears.

George.

edited by george... typo's.

Edited By mechman48 on 28/10/2020 16:35:51

Have tried making one, although not quite in the form shown.

Based on the first couple of cuts, it looks to be an interesting tool.

Thanks for bringing it to our attention!

Howard