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Thread: Small chisel problem
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3rd September 2012, 09:00 AM #1Senior Member
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Small chisel problem
Hi all
I have an unknown brand (looks old) 1/4" bevel edge chisel I bought very cheaply. I have sharpened it with 25 degree bevel to 6000 grit waterstone. I have been using it to clean out some dovetails (my very first) and I seem to be literally folding over the edge of the blade each time I use it. This obviously renders it useless and I have to stone off the bent edge and resharpen. It has happened a couple of times now with only a couple of uses.
Should I increase the bevel angle to say 35 degrees, giving it a little more thickness?
Or should I just toss it and get a new one?
Sorry I have no photo at the moment.
Regards
Pedro
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3rd September 2012 09:00 AM # ADSGoogle Adsense Advertisement
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3rd September 2012, 09:34 AM #2
What timber are you using it on? If it's quite hard then you probably need a steeper angle. I suggest you try 30° before going to 35°. If it won't hold an edge at 35° then there's something wrong with the steel.
It may have lost it's temper (like I do when a blade won't hold an edge ) from being overheated on a powered grinder; it may never have been hardened and tempered correctly at manufacture; or it may just be made of cheese.
HTH.
Cheers, Vann.Gatherer of rustyplanestools...
Proud member of the Wadkin Blockhead Club .
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3rd September 2012, 10:53 AM #3
The Chisel.
Hi Pedro,
Like Vann said, I would heat the last 25mm. to Red Hot, then watch to colours change after taking from the Heat, when it goes to a Straw Colour, dunk it in the Water / Oil, which is up to you. If it doesn't work, do it again.Regards,
issatree.
Have Lathe, Wood Travel.
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3rd September 2012, 11:02 AM #4Jim
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Like Vann said. If it's old and any good the chances are that the temper's been drawn in grinding. Can you see any sign of a logo? One problem is that cheap stuff has been around a long time serving useful purposes such as opening paint tins.
Cheers,
Jim
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3rd September 2012, 11:41 AM #5
G'day Pedro.
You've only mentioned one bevel angle, are you putting a secondary bevel on the edge?
http://www.inthewoodshop.com/Woodwor...gStrategy.htmlWe don't know how lucky we are......
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3rd September 2012, 01:43 PM #6Senior Member
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Hi all
Thanks for the quick replies
Vann, I will try the 30 degrees tonight and see how it goes.
Heating the end sounds good, that will mean a fire with the neighbor (he is not happy unless you can see the fire from space) and a bottle of American Honey Bourbon. Not sure I should be doing that sort of project at that time, but hey how bad could it be?
Jimbur it looks old but no logo, and it was definitely not someones pride and joy. It was a bit bent when I got it.
Seanz I have not bothered with secondary bevel as the face is so small and my diamond stones are very fast, but I will give it a go.
Thanks everyone
Pedro
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3rd September 2012, 04:03 PM #7
Try 30 degrees first if you are paring hardwood end grain. Go to 35 degrees if you are chopping.
If you plan to re-heat treat the chisel, I have a simple method on my website:
http://www.inthewoodshop.com/ShopMad...tTreating.html
Regards from Perth
DerekVisit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.
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3rd September 2012, 07:28 PM #8Senior Member
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Thanks Derek
Regards from Townsville
Peter
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3rd September 2012, 09:30 PM #9
Peter, you said the chisel was bent when you got it, which suggests to me the whole blade is soft, so it's unlikely that your problem with curling edges is due to over-vigorous grinding. It may have been softened by some 'accident' in its life, like being caught in a house fire, but it's more likely it has always been a paint-can opener - they're not all that rare, unfortunately.
I would try Derek's two-step method of hardening, then tempering. If the steel doesn't harden (i.e. too hard to file) after step 1, stop there & waste no more time on it - you have a piece of cheap, low-carbon steel, that is masquerading as a chisel.............
Cheers,IW
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3rd September 2012, 11:34 PM #10Senior Member
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Hi Ian,
Executive decision. EBay. Stanley blue handle chisel, I have some already, just not in that size, and they are OK for me.
I don't have a burner
I will wait till we have another backyard fire, see if I can improve the soft one.
Thanks for all the info, a new experiment to look forward to!
PS Ian, the saws are great!
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4th September 2012, 08:57 AM #11
Peter, I think you are making life excessively difficult trying to harden & temper on a backyard fire, but as you say, an interesting experiment! Fires & fireplaces are good for annealing the whole piece, because you can just chuck it in the fire & leave it til everything cools, nice & slowly. Over-cooking can ruin the steel permanently (no big loss in the present case, perhaps, but annoying), which is easy to do with a blown fire like a forge (DAMHIK! ) but less likely in an ordinary stove or not-too-heroic fire. For hardening & tempering, you need some control, so a much smaller heat source would be the go. You can watch the metal closely, & quickly quench it when it reaches red hot. I reckon it would be infinitely easier to borrow a couple of torches (one won't do the job on its own, unfortunately) for the few minutes it will take to toughen up your chisel.
Pleased to hear my children are behaving themselves.....
Cheers,IW
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4th September 2012, 09:16 AM #12Senior Member
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Thanks Ian
I have taken the easiest path, bought another chisel, and will put aside the old one for now.
I will hunt around for appropriate heat sources. Interestingly enough, a couple of weeks ago I was on a farm stay/school camp out west with my eldest son, where we watched a young calf get branded. The iron was heated in a lovely gas powered forge, and I looked at it very closely, thinking to myself "I could do stuff with this thing" I wasn't sure what at the time, but now I know.
It had many uses, the forge. After castrating the calf (in front of a horde of horrified 10 year old boys and girls) the bush oysters were sliced up and cooked on the top!!
Regards
Peter
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4th September 2012, 09:46 AM #13
Peter - yes, I grew up on a farm up on the Tablelands north of you, & well remember the annual branding & castrating rituals. The dogs got the 'oysters' raw, on our place, though.
We had an old hand-cranked forge, which was a source of much fun (and a few 2nd degree burns! ) for us boys. We were greatly fascinated by the different melting points of metals, & spent many happy hours collecting charcoal after the bush fires, and reducing various objects to unrecognisable shiny blobs. A good deal of rough & ready bush blacksmithing was done on that forge, & I learnt the rudiments of heat-treating watching my dad fixing various agricultural bits. I still have a couple of draw-knives I made from old truck springs during my earlier woodworking days. The design isn't the best, but they take an edge ok, and are occasionally just the right tool for the job in hand. I miss that old forge, and thought I'd snaffle it after the old pot moved on, but one of my brothers or BILs beat me to it. It's on my to-do list to make a forge "one of these days".
I'd recommend just keeping the crook chisel as-is. We all need a chisel or two that you don't care about, they are very useful when you don't want to risk damaging a proper tool. I've got 3 of them that I keep for just such jobs....
Cheers,IW
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4th September 2012, 11:18 AM #14Senior Member
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Hi Ian
I'm sure a propane gun will fall into my shopping trolley at some point, and I will have a go at hardening it. Not a priority at the moment. As you say, a chisel I don't care about will probably be more useful.
They had to cook the "oysters" for us and the kids to sample................
Unfortunately, if the Dads' didn't try it first, the kids wouldn't either.
The things you do!
Peter
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