Est. 1998 — 27 years of woodworking knowledge
a good reason to temper tools!
Gary B in Central NY
>5 minutes ago I was putting the finishing touches on a wenge handled marking knife I made. the blade was an old jigsaw blade that I had annealed, ground, hardened and sharpened...I figured, it's only a marking knife, why temper?!? I stuck it in the vise so I could put some BLO on the handle, my heart sank as I heard "tink". any ideas to save the handle? it's epoxied on......
Re: a good reason to temper tools!
Bob Fawcett
>If there is some blade sticking out a little heat will make the epoxy turn loose. Wrap the handle with a wet rag to protect it and heat carefully with a torch. You should be able to pull it out with a pair of pliers.
Re: a good reason to temper tools!
Gary B in Central NY
>I just fixed it, it took a while to realize that I could just shave the handle down and reveal more blade....now I have to grind again, then maybe I'll temper it!
Heart breaking Sounds
Todd O. Cronkhite Maine Native now in Jax Fl.
>Gary,
Glad you got it it fixed up.
Your story reminds of the time iwas going a 5 minute plumbing job un
derneath the vanity in the Master Bathroom and heard the sickening sound of "snap", which turned out to be a piece of PVC pipe. Not only did the pipe break behind on the backside of the vanity, but behind the sheetrock no less. Repairs included removing the vanity, cutting out some sheetrock, repair pipe, repair sheetrock, reinstall vanity. Total time spent working in that cramped little space, 5 hours!
Todd O.
Re: a good reason to temper tools!
Derek Cohen (in Perth, Australia)
>Gary
Glade you sorted it out. For future reference, a little heat will soften epoxy enough to remove a blade. BUT I do NOT use a flame - I use a hot air gun (like a paint stripper). This is much less likely to burn anything in the area.
Regards from Perth
Derek
Re: a good reason to temper tools!
thomd coralseacat@yahoo.au
>Heat also improves the post cure and the resistance of the material to separation by heat. When I first started working with epoxies I used to just boil parts appart. Like beginer's luck that has rarely re-visited. I worked my way up to one situation in which I tried to remove a golfclub head and had it almost go off like a roman candle it needed so much heat. In general this kind of thing may not be worth saving. Try spliting and bandsawing and save what you get. Heating up glue is probably not worth the risk to your body.
When it comes to hacksaw blades, the better ones are often HSS so they don't temper. And the in any case one should be able to grind the HSS as agressively as one want without ruining anything so the thermal cycling might not have been productive. On carbon hacksaw blades it would be pretty much as you describe.
Re: a good reason to temper tools!
Bob Hackett
>Most folks are very surprised the first time they see a hardened blade blank dropped on a concrete floor shatter like glass.
Hardening also makes the blade brittle and puts stress into the blank.When you temper you trade off some of the brittleness and hardness for toughness and the ability to bend and return like a spring.
Sorry you had to find out the hard way but it`s a lesson most tool makers go thru at least once.It`s also one that you`ll remember for a long time.
Good luck with the next project.
Mainely,Bob