Cutting a fine groove

It would be really interesting to test a New Old Stock 1960 hacksaw blade against a modern one to see if they really were better. Personally I doubt it: if old tools were so good, why the cars so bad?

Anyway, better or not, modern hacksaw blades are rather likely to have been made differently to an older one. Only the teeth are HSS and the rest of the blade is flexible rather than hard. This means they're less suitable for conversion into a grooving tool.

Dave

All hard hacksaw blades are still available from good tool suppliers. I never use anything else!

The modern bi-metal blades are widely sold and many people seem to think they are the only type in town. Even some sales reps. deny the existence of all hard blades.But if you persist and are willing to pay the extra then you can still get hold of them. As the previous poster mentioned they don't like bending and will shatter if not used correctly (hence the popularity of the bi-metal ones) Unfortunately many users have never been shown the correct way to use a hacksaw and would find it an expensive learning experience.

At work I can leave my hacksaw out on the bench and no-one will use it because they hate the blades snapping. .......BUT I am the only one who can cut a straight line and the younger lads think it is some kind of magic secret that only I know. They will confidently state that it is impossible to do this with a hacksaw even when I demonstrate that it isn't.

Another source of good HSS is machine hacksaw blades, the old fashioned reciprocating donkey type saws.Not the modern band type. These make excellent tools and because they are quite wide there is a lot more strength in them.

I have a sort of rear tool post that is fitted with a very thin slitting saw, as a cutting blade. It is rigidly fixed, with the tip of the tooth in use set at centre height. Works very well as long as I keep a stiff artists paintbrush handy to keep it clear of swarf. I started using it for some parting off where I needed minimum waste, but it does cut very nice grooves.

Maurice

I am also a fan of the all hard blade and fitted in a decent frame will give you the best chance of cutting where you intended. Cutting conduit on the bender vice unit will result in a broken blade very quickly if you do not use the flexible version. So it is horses for courses, on a fitters bench with an all hard blade and a decent frame a square cut is possible. Having the right equipment will not guarantee a good result but not having it will almost ensure a poor result.

Mike

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

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

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.

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

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).

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?

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