Cutting a fine groove

[HopperParticipant @hopper]

Posted by Russell Eberhardt on 25/06/2017 11:08:45:

Posted by Hopper on 16/06/2017 00:21:54:

Does nobody grind their own toolbits anymore?

Yes, here's one I made earlier. A 1 mm parting tool for parting a number of parts off 1/8 in silver steel.

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Well done. Job and finish in less time than it takes to make a post on a forum thread.

[Ian Skeldon 2Participant @ianskeldon2]

No Dave, I really do think that the old, fully hardened (and tempered) hacksaw blades were generally better. As Max points out, the method or stroke for using them has to be correct but once mastered a good quality straight and square cut would be achieved many times. I have several differing types of knife made from the old yellow 2" recipricating saw blade and they still sharpen up in just a few strokes on the stone.

Muarice that sounds like it could be worth looking into, someone mentioned a slitting saw early on but I didn't realise that they came in that thin.

Thanks again for all the suggestions.

Ian

[not done it yetParticipant @notdoneityet]

I didn't realise that they came in that thin.

A quick check might have revealed they are available in less than half the width you are aiming for. 0.2mm is readily available.

One advantage is that the blade can be easily supported right out to the teeth as the cut required is that shallow.

[Gordon Brown 1Participant @gordonbrown1]

Until the latter part of 2016 I was unaware of the existance of all hard hacksaw blades but then discovered them in an unpleasant way. When trying to cut a length of 50mm steel tube I used a saw I hadn't tried before, taken from a batch of engineering tools I had bought at auction. About half way through the cut the saw jammed, the blade shattered and somehow my right hand moved forwards onto the broken end of the blade. This extremely sharp edge ran half the length of the back of my middle finger, opening it up down to the bone. Cue one trip to A&E where the doctor who examined the finger found that the blade had followed a path just to one side of the main extensor tendon. If it had deviated by a couple of mm it would have severed the tendon and I would have lost the effective use of that finger, making it the closest call I've had in the workshop.

I'm in no doubt that all hard blades are a valuable addition to any workshop but clearly you need to be able to use them properly, which equally clearly I can't! I'll be sticking to my usual Sandvik bimetal blades in future.

I too still grind my own lathe bits and I've made a couple for cutting 0.5mm grooves in silver steel rods to take circlips, the rods becoming replacement shafts for rc plane electric motors.

Edited By Gordon Brown 1 on 27/06/2017 08:02:08

[Ian Skeldon 2Participant @ianskeldon2]

Not done it yet, Yes, I apologise for not checking out your suggestion any sooner, but now I have and I am a wiser man for doing that, thank you for taking the time to help me out.

Gordon Brown 1, don't give up, I bet there's not a person here who has used the fully hardened hacksaw blade and not snapped a few, thankfully you didn't sever the tendon.

I do grind (re-shape or sharpen) my lathe tools and drill bits ( I also fly rc models but mainly glow).

[NigeParticipant @nige81730]

I broke a jigsaw blade yesterday and realised it snapped rather than bent. Would jigsaw blades make good parting off tools in a similar manner to hacksaw blades?

[Ian Skeldon 2Participant @ianskeldon2]

My answer to that would be it depends on several factors, such as, how well you grind the old blade into a parting tool form, you will probably need to quench it frequently so as not to over temper it during grinding (happy to be corrected if that is wrong). Also the depth required and the material that you will be parting off with it, bear in mind that a HSS blank has a lot of body supporting the thin cutting tool which helps keep it in one piece. But if you can grind it up and hold it firmly, I don't see why not, several people smarter than me have said here that they have used them to cut grooves, let us know how you get on Nige.

ATB, Ian

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