Cleaning up an old woodie as a user. Super hard iron?

[Boysie]

I bought a nice old Varvill coffin smoother a year or so ago, and have just got around to cleaning it up and trying to put it back into a useable condition.
It's my first wooden bench plane, and I'm struggling a bit with the iron.
Not sure if it's original to the plane, but the iron is by Ward (W&P) and is 2 and a quarter inches wide.
I've de-rusted it, but unfortunately it had some quite heavy pitting right near the cutting edge. I ground about 2/3 of a mm off to get past the worst, and plan to put a bit of a back bevel on to deal with the rest.

Now I'm trying to set a new primary bevel, but it's taking a surprisingly long time, even with a 60 grit zirconium belt on a pro-edge.
The soft iron grinds fine, but the hard stuff comes off really slowly, and mostly just seems to get hot.
The belt isn't brand new, but it was far from worn out when I started.
It's been a while since I did any heavy grinding, but I don't remember it taking more than half an hour to set a new primary bevel on a modern thick iron.

Do I just need to be more patient?

Have I been daft trying to grind an old tapered iron at 25 degrees?

I've tried putting a relief bevel in the soft iron to reduce the amount of metal sitting on the belt, but it doesn't seem to help much.

How the hell did people manage to grind a chip out of one of these on an oil stone, or even a hand cranked grindstone?

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[ED65]

Yes some old irons are famously hard. And as the steel composition varied somewhat some are very tough (wear resistant) as well. In combination it makes for a great long-lasting cutting edge, but just as with modern high-end steels it makes the sharpening side of things onerous.

Have I been daft trying to grind an old tapered iron at 25 degrees?

Obviously it's up to you what you do but really it's not needed.

All you need is clearance on a bevel-down plane. For a plane bedded at 45° the working part of the cutter's edge could even be around 40° and the plane will function, and some users (including Paul Sellers) report they can't tell any difference in the effort needed to push with very different edge angles.

How the hell did people manage to grind a chip out of one of these on an oil stone, or even a hand cranked grindstone?

Good question! Possibly by the time this iron was made they had carborundum to work with, but before that who knows?!

In terms of what to do now, have you got a very coarse diamond plate? I've never compared performance between zirconium and diamond but there's nothing diamond won't abrade and while it wouldn't be quick work it'll do the necessary.

 

[Cheshirechappie]

The old irons are made from straight carbon steel, and whilst some were not tempered back as much as others, they were all tempered enough to loose the brittleness of hardening - enough, at any rate, to give good service in their intended duty. It might be a wee bit harder than some straight carbon steel irons, but it won't be so hard as to be ungrindable. After all, the makers put the initial bevel on it - though they did use wheels of much larger diameter and generally higher peripheral speed than most of us have to hand!

If you're trying to grind past a chip, you'll be taking off quite a lot of hard metal (and even more softer backing metal), so it is going to be a slow and steady job. The Pro-Edge is a good piece of kit, but it's intended to touch up smaller tools in service, not for production grinding on larger edge tools, so a wide laminated plane iron is pushing it's capabilities.

There may be some benefit to filing the softer backing, putting a slightly shallower bevel on it to relieve the Pro-Edge belt's work a bit, and avoid the chance of clogging the belt with softer wrought iron. Also, cool the edge frequently whilst grinding, and go a bit at a time - don't expect the small machine to whack off hard steel like a large production grinder.

Another technique that might help is to offer the blade 'straight on' to the belt, grinding back the edge to just remove the chip (so you end up with, in effect, a 90 degree 'bevel'), then file off the backing and grind the primary bevel almost to the edge, until stoning will put the secondary bevel on.

Take your time, and you'll get there. After all, it's a job you'll only have to do once. Subsequent regrinds will only have to take off enough to restore a primary bevel, not get past a big chip.

 

[custard]

You've ground modern thick irons on your Pro Edge, so this shouldn't be giving you the slightest problem whatsoever.

The fact that you mention overheating makes me suspect your belt is clogged or worn. Personally I use a 60 grit ceramic belt on a Pro Edge, and it'll take out a nick in a 4.5mm thick A2 iron in under ten minutes. The fact that you're still struggling after half an hour suggests something's seriously wrong somewhere!

Turning to your choice of woodies, I'd question if you're investing your time where you'll get the most return. The best first choice for a woody is a jack. With a reasonably aggressive camber that's a tool that can rightfully earn it's place in almost any woodworker's tool box.
A wooden smoother, though a delightful tool, isn't quite such an automatic first choice. It needs to be settable with more precision, and if your plan is to get through the pits with a back bevel, then you'll be left with a high pitched tool that's harder to push through the timber. The delicate grip and ultra light weight of a woody smoother means that just feels wrong.

My advice would be first, fit a ceramic 60 grit belt. Then, put this smoother aside and find a decent wooden jack without any pitting of the iron, there are loads of them out there, so why settle for anything less?

 

[Boysie]

Thanks for the replies folks.
I'll try a fresh belt to get the job finished, and will keep my eyes open for a nice wooden jack.
I can always come back to the smoother once I've developed a better touch for setting a wooden plane on something a bit more forgiving.

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[D_W]

If the fresh belt doesn't work, it might be better to put it in your kitchen oven at 400 degrees for an hour. Do the first cycle with the iron closer to the front (in case the oven is hotter than the dial indicates). No matter what carbon it is, that should bring it down to about 60 hardness. If the carbon content is too low or too high for the iron to get in that hardness range, it won't be a good iron, anyway (and as much as folks talk about defective older irons, the steel content was pretty consistent, even if the hardness from maker to maker differed a lot).

I once had a beautiful almost unused griffiths try plane with a fantastic clean and never flattened ward iron. Rust free and all, the kind of iron that costs more than most planes. When I went to flatten it, I found out why nobody used it. It was either untempered or nearly untempered. I ended up selling the plane, but wish I hadn't.

As nice as it is to have a hard iron just to be fascinated about it, an iron 60 hardness that grinds and sharpens with relative ease is far more practical. The super hard irons (like untempered level) always give up little chips when you plane with them, anyway. They still work fine, but really no better than one that's tempered medium straw color.