Anyone try LV's Robert Sorby Paring Chisels?

[Patrick Chase]

I think also that some of this flex is incidental to trying to harden a 9" long, 1/8" thick blade without warp....

My own experiments on getting something like this to work right resulted in a chisel body which was normalized with only the last 1" or so hardened and tempered... And it has this flexy sort of feel to it... It's pretty easy to get it to come out right (and clean it up for a decent flat back) with only the last inch hard... Try to harden much more and warp becomes a big fight.... I made some pretty ugly chisels when I was trying to get them mostly hard..... Never mind that 1" of hard chisel end is probably 3 lifetimes for me..

I think you know this, but your wording could be interpreted as implying that only hardening the tip somehow makes the chisel more flexible. It doesn't. The material property that determines stiffness is Young's modulus, and hardening doesn't change that. As the oft-cited line goes, if it rusts it's 29 Mpsi (in reality there is a small amount of variation based on alloy composition, but you get the idea). A chisel that's hardened along its full length will have the same stiffness as an otherwise equivalent one (same cross-section, alloy, etc) that isn't hardened at all.

Hardening greatly changes the yield strength, but hopefully nobody is bending their chisels *that* much :-).

[Stewie Simpson]

think also that some of this flex is incidental to trying to harden a 9" long, 1/8" thick blade without warp....

John; Robert Sorby's history of working tool steel dates back to 1828. Your claims of "incidental" are absurb.

[Patrick Chase]

John; Robert Sorby's history of working tool steel dates back to 1828. Your claims of "incidental" are absurb.

I think that John meant "incidental" in the sense of "a side effect of", which would not be a criticism of the maker as you seem to have concluded.

I'm still not sure whether his post was based on an incorrect premise about hardening and stiffness, but either way I don't see any reasonable reading in which it's derogatory.

[Stewie Simpson]

Possibly Patrick; but this relentless focus of comparing 1 steel against the other is getting rather tiresome. (imo)

[John C Cox]

What in the world are you going on about now Stewie? How can you take offense at such an obvious statement? And who (in this thread) was going on and on about this or that steel?

Is Sorby somehow a sore spot with you? Is there some reason you want to throw a rock at somebody who points out that Sorby did a lot of work to get their paring chisels right.

[Frederick Skelly]

Man, I'd sure like to hear more about those Sorby Paring Chisels that LV sells.....

[Patrick Chase]

Possibly Patrick; but this relentless focus of comparing 1 steel against the other is getting rather tiresome. (imo)

What in goodness' name are you prattling on about?

This is one of those rare threads in which no steel comparisons have been made. Not a single one. I did remark about the problems that Narex' practice of doing only pre-HT machining causes in a long paring chisel, but said nothing at all about the steel itself.

For the record, I'm in the process of upgrading to Japanese parers (usu nomi). I subjectively prefer a more rigid tool, but find the Japanese solution (shorter blade and longer, slightly cranked handle) more appealing than Narex' brute-force, all-blade approach. If I were going to continue with Western paring chisels I'd go with the Sorby ones hands down. I've used one once in somebody else's shop, and they're much more refined in feel and balance than Narex.

I also like the Blue Spruce design but have concerns about their... err... choice of materials (carefully avoiding Stewie's favorite word here).

[John C Cox]

I'm still not sure whether his post was based on a bogus premise about hardening and stiffness....

Bogus? Come on now - you know better... Nobody cares about youngs modulus when their too-hard paring chisel snaps in half....

My original point was more about problems with a 9" long chisel warping into a pretzel if the entire length was hardened... I noted Sorby doesn't harden theirs full length on purpose.. But so be it....

[Patrick Chase]

Bogus? Come on now - you know better... Nobody cares about youngs modulus when their too-hard paring chisel snaps in half....

My original point was more about problems with a 9" long chisel warping into a pretzel if the entire length was hardened... I noted Sorby doesn't harden theirs full length on purpose.. But so be it....

Understood. I'd note that that can itself cause problems with straightness. I've seen plenty of tip-hardened tools like that with a sudden kink right where the martensite (or bainite if Narex) stops and the pearlite starts. The transition becomes obvious once you've honed the tool a bit, as the unhardened parts don't polish.

My understanding is that a skilled heat treater can control which way that kink goes by being clever with insertion angle and agitation. Narex doesn't seem to have figured those tricks out, though, or those tricks may be less practical in molten salt.

[Jim Koepke]

but this relentless focus of comparing 1 steel against the other is getting rather tiresome. (imo)

When posts on a subject gives me that 'tiresome' feeling, it is easy to just skip over them. Eventually they run their course and drop off the page.

jtk

[Stewie Simpson]

Fair call Jim.

regards Stewie;