HSS...Do these look like it, how would I tell?

In the collection of lathe tools I inherited there are some that are clearly marked HSS. The photo below shows tools of a steel that look identical to the marked ones. Is it safe to assume they are HSS and is there a way I can tell please? They are sized from 3/16" to 3/8".

Yes. And the ones that aren't, won't cut very well and/or for very long! You can also try a file on them, won't make much of a mark if HSS.

Hard to tell just by looking but easy with the help of your bench grinder. Just look up " spark test for HSS " and you should get a drawing of the type of spark to expect.

Norman

Edited By NJH on 31/07/2017 20:51:42

The sparks produced by a grinding wheel can be used to identify ferrous metals

It may be harder than it looks - I've not tried it myself.

Dave

Edit Must learn to type faster - Norman got in first!

Edited By SillyOldDuffer on 31/07/2017 20:58:12

Thank you guys. I will look up the spark test and try it out

You'll also risk wrecking you good files.

Try with a magnet.If not attracted it can be stellite.

Nige, spark test is by far the easiest and best way and probably the most reliable for home use, best way to learn is to try some known steels on your grinder. HSS will have a shower of dull nonebussting sparks, check this against a carbon steel and you will see larger shower of bright busting sparks. This will of course not tell you the precise type of steel but gives a good indication. Cheers John

Hi Dave,

Do you type with one finger,like me ? I tried using two but the result was gibberish . Oh to be young again [well not too young ].

I got a lot of bits like that when I bought my first old lathe. Only a few pieces had any markings on them but they were all HSS of one sort or another judging by how well they cut and held an edge.

I use an electron microscope in work and can identify the % of elements in alloys so if you really want to know I am happy to help.