Cracks in old chisels

[Blacky's Boy]

One of the young guys here at work has expressed an interest in wood working and I decided to help him out by restoring a set of old chisels for him. God knows I have enought of them laying around! So I derusted a nice set of socket firmer chisels and noticed some weird cracking on the bodies. To my untrained eye, it looks like they were heated up insufficiently and then someone tried to bend them. I'm thinking that these chisels are shot. I have a feeling that these fractures will effect the structural integrity of the chisels and will cause them to crack at the stress line. Do you agree?

I have others (although not as long) that would work in thier place.

Additionally, I found the remains of a logo. I can't make much of it out andwould appreciate some insight as to the mfg.

[adamcherubini]

How straight are those chisels? Any evidence of being used as pry bars? Any curve? I feel like that may have been a heat treating problem- possibly a quenching problem. Like a cold water quench that caused that. I feel like those cracks may not have been obvious when the chisel was new.

I always quenched Water Hardening steel in oil to avoid such problems. I had chisels bend during quenching if I put them in wrong.

[AHill]

It is quite possible the chisel was bent, then someone used a torch to heat the area that was bent to bend it back, then water was poured on just the heated area, causing the localized cracking. The differential heat would cause that localized cracking. I can't make out any logo, so I can't help you there.

[Blacky's Boy]

The chisels are "somewhat" straight. "Somewhat" being the operative term here
Of course the wider ones are fine. It's the narrow parting chisels that look a little "banana like". These two with the cracks on them are actually not that bad. But those cracks realy threw me for a loop. I'll clean them up and see how they look but my game plan for now is to use some other chisels of a similar width.

[adamcherubini]

the narrow parting chisels that look a little "banana like".

The banana shape is exactly what happens when you quench “wrong” either with water or by simply dropping a thin tool directly into the quenchant.

When I quench thin chisels, I hold them perfectly vertically, and slowly introduce them into the bath. Most times they only go in 3/4 of the way to the bolster. No need to harden the entire blade. This was the only way I figured out to stop tools from turning into bananas.

[Stwood_]

Welcome Dom.

[Ron Brese]

One of the young guys here at work has expressed an interest in wood working and I decided to help him out by restoring a set of old chisels for him. God knows I have enought of them laying around! So I derusted a nice set of socket firmer chisels and noticed some weird cracking on the bodies. To my untrained eye, it looks like they were heated up insufficiently and then someone tried to bend them. I'm thinking that these chisels are shot. I have a feeling that these fractures will effect the structural integrity of the chisels and will cause them to crack at the stress line. Do you agree?

I have others (although not as long) that would work in thier place.

Additionally, I found the remains of a logo. I can't make much of it out andwould appreciate some insight as to the mfg.

Whether those are water quench cracks or not there is obviously some stress in that chisel. I wouldn't trust it.

Ron