Cutting 25 thou grooves for a couple of circlips

[Andrew TinsleyParticipant @andrewtinsley63637]

Pondering how to do this operation, it suddenly occurred to me that my standard hacksaw blades are 25 thou thick in the backing area. Are any of the commonly available blades made from HSS, if so, I may have found the ideal grooving tool.

However I suspect that modern blades have the teeth strip, electron beam welded to the backing. So the backing is unlikely to be HSS. I can give it a try tomorrow, but does anyone know of a blade that could cut the grooves required. It doesn’t have to last very long!

Andrew.

[JasonBModerator @jasonb]

I’ve ground HSS that thin, just don’t make the narrow end any longer than needed but these days use inserts.

[peak4Participant @peak4]

Many of the better blades may be bi-metal welded but some blades are “All Hard”
Amongst the all hard ones are carbon steel and HSS.
This is just a random example; I’m assuming you only need one or two
https://www.ebay.co.uk/itm/267697539540
I have a selection here at home, but only 24tpi in all hard.
If you want to go down that route and struggle to find any, drop me a message.

Bill

[DurhambuilderParticipant @durhambuilder]

I quite often use broken hacksaw blades as either grooving tools or narrow parting off tools. Some hold their edge quite well others not so. A simple rough holder can be knocked up on a few minutes, one day I’ll make a more photogenic one. Pictured also is a 5/32 silver steel valve stem with a  25 thou e clip grove.

[bernard towersParticipant @bernardtowers37738]

Be careful with your choice of blades you need all hard ones not bimetal. If you have grinder you change them down to 10 or 12 thou!

[Michael GilliganParticipant @michaelgilligan61133]

Starrett RedStripe

MichaelG.

[noel shelleyParticipant @noelshelley55608]

Eclipse all hard. If the blade is broken, stick a short end in the vice and bend, if it snaps then it will be all hard and make a good parting/ grooving tool. Noel.

[JasonBModerator @jasonb]

Could a bi-metal be used if you placed the cutting tip where the wavey “set” of the blade is central and you flatted off any of that set behind the tip. Does not matter if what is backing up the blade is soft as it is not doing the cutting.

[JasonBModerator @jasonb]

Yep, just as I thought, no need for all hard as it is just the cutting edge you will be using not what is backing it up. 12mm steel, 500rpm. Front mounted QCTP with plenty of overhang. That is also the blade I used when everyone was saying you can’t use a standard drill to put holes in hacksaw blades.

 

[egaParticipant @ega]

I suppose that it would be more challenging to cut *internal* grooves.

[JasonBModerator @jasonb]

Depends on the bore, if big enough just drill a short length of hacksaw blade and screw it to the end of a bar and away you go.

If the hole is not very big small crabide grooving tools are so cheap it is hardly worth bothering to make or grind something.

[bernard towersParticipant @bernardtowers37738]

the trouble with bi-metal is there is less room to play with for shaping and grinding the tool tip.

[JasonBModerator @jasonb]

Well I suppose if you have a need for a lot of top rake you might cut into the backing but again the actual cutting tip should still have some HSS on it. Or just grind the blade with a flat top and hold it at whatever angle you need to get the desired top rake.

I managed to get a few degrees top rake on the one shown in the video and can just see the weld line is intact. It was just done freehand on a linisher, no doubt those that have spent half their life making and finishing a quorn or similar could do better. It actually have more top rake than the HSS blade who’s holder I used and about the same as an insert all of which have no prroblem grroving and parting ferrous an dnon ferrous metals.

[JasonBModerator @jasonb]

Close up showing the weld line

[Michael GilliganParticipant @michaelgilligan61133]

A useful reference photo, Jason

Thanks

MichaelG.

[Andrew TinsleyParticipant @andrewtinsley63637]

Thanks everyone for your input,

Gave it a try this morning and using an old Starrett red line blade, I had no trouble in cutting the required 25 thou grooves. I also tried Jason’s tip of using the “tooth side” of a bimetallic blade. This worked as well.

So thanks again,

Andrew.

[JasonBModerator @jasonb]

here’s one to keep Michael amused this evening. 😊😊😊

[Michael GilliganParticipant @michaelgilligan61133]

Neither designation would mean much without great elaboration !

… I just know them as being very good “all hard” blades

MichaelG.

[Grindstone CowboyParticipant @grindstonecowboy]

I can vouch for the fact that Starrett are very good blades, having bought some a few years ago on Michael’s recommendation.

Rob

[Andrew TinsleyParticipant @andrewtinsley63637]

I must admit that I use the Starrett red line blades almost exclusively. They are very good blades for my usage. Still have some Eclipse blades and I doubt if I will ever use them up.

Andrew.

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