New blade for a Record 77a

[--Tom--]

At least 15 years ago I picked up a record 77a bullnose plane on eBay thinking that I needed one.

It arrived and I sharpened it up as usual but found it was pretty useless compared to a block plane or a sharp chisel. I couldn’t get it cutting properly and so it went in a drawer.
Now I’m in the process of finishing off my workshop I was unpacking everything and came across it again. It’s a nice little thing and so I thought I’d give it another go.

The bevel showed my sharpening 15years ago wasn’t as good as it is now, so I carefully reground it, honed a fresh bevel and gave it another try on a bit of pine from the offcut bin.

It was still dire, refusing to take a nice shaving. Taking the blade out to have a look, the fresh bevel had completely crumpled, as though I’d just tried planing 60 grit sandpaper.

Intrigued I found I could easily deform the bevel with my fingernail, showing the blade was nowhere near hard enough.

Rather than just putting it back in the drawer, or selling on eBay to disappoint someone else, I thought I’d make up a new iron and see if I could get the plane to be able to, well, plane.

i ordered a piece of O1 in roughly the right size, a bit over on width and 3mm thick as supplier didn’t have it in 2.5mm, and thought thicker was better than thinner

After tracing round the outline I set to with a hacksaw to cut to shape, slowly raising in the vice to control

A tidy up with a file and I had the rough shape

gave myself a bit more length after first checking it would fit with the depth a

Then was the fiddly bit, making a nice neat slot. Not having a mill I drilled a hole at each end and then after finding my needle files woefully inadequate I chanced a Pegas wood cutting blade in a fretsaw. Luckily it worked and meant I could saw out the waste big enough to get one of my better files in for tweaking. Need to order myself some proper metal cutting blades, but was impressed by the wood blades

Next was heat treat prep, which involved making sure all the internal corners were rounded to protect against stress risers and cracks. Then a coat of anti scale compound, to protect against decarb, and also try and avoid having to do too much clean up work to polish the back. Without a surface grinder lapping away pitting from scale is no fun.

next was heat treating

 

[Bm101]

Looking like an interesting project Tom. Couple of questions...
Have to say, I'm interested in the anti scale compound. Always interested in new ideas. I stumbled upon it recently looking at some o1 steel I'm treating so posted a question here:
https://www.ukworkshop.co.uk/threads/anti-scale-solutions-heat-treatment.125613/#post-1394984And, as usual, was met with some great responses.
As the last post suggests I bought some wire and boric acid. Price wise it seemed a lot cheaper than the liquid solutions for a small amount of treatment I would use.
Like (a less experienced) you, I'm keen to avoid any removal of scale by abrasion. If we can avoid it in the first place , that's ideal. If you haven't seen it, the weak acid solution might be a game changer matched with preventative methods. I'm ready to heat treat, just trying to find some suitable free time/ daylight / dry weather. But I can post results.
One more beginner question... I'm sure there's a reason, but why not just heat treat the original iron?
Thanks for posting.
Regards
Chris

 

[AndyT]

Wow, that's impressive. I was thinking "you can get them from Ray Iles" but I see that I'm a bit late with that suggestion!

https://www.oldtoolstore.co.uk/repl...-and-prestons-equivalent-plane-iron-190-p.asp

 

[lurker]

Now that the original blade is surplus, try grinding it back and resharpening.
Maybe the previous owner blued the edge with poor grinding and honed back to clean steel

 

[--Tom--]

Cheers, it survived quench last night, so will head down and do some more tonight.
Borax works well as a flux when laminating, and would work as an anti scale, but it also has a habit of eating the inside of your forge. Similar home brews use graphite powder (like locksmith sprays) that help avoid the decarb you get.

Next time I harden something up I’ll put a piece in uncoated to show the difference. Whilst you can just heat and quench O1, it benefits from a soak at temp. It’s that extra time at temp that can affect surface finish.

HTing Stainless is where you really need protection, for carbon steels it’smostly for convenience.

I ran a file over the old one and it was all soft, not sure it had ever been properly hard. It’s not marked so may have been a replacement blade itself. I may see if it will harden up, but always a gamble re-heat treating something already made out of mystery metal.


I looked at the Ray Isles, and effort wise just buying one was a no brainer, but it was do this or carry on sorting stuff out....

 

[--Tom--]

So if anyone is interested I followed this recipe for heat treat

Preheat to 1300f hold for 10 mins

Then heat to 1475f and hold for 20 mins

Quench into a medium fast oil as soon as it comes out, thin sections drop temp quickly!

Tempering:
I’ve left it on the hard side, with 2 temper cycles at 360f for 1 hour each time. The first was straight after quench yesterday the second was today.

If it needs it I can always do a third temper at a higher temperature, but can’t go the other way without rehardening.

It came out of the oil looking like this

After a quick clean up it’s looking good

This side will be the back

This side showed a bit of scale from where I left the compound to drip off it formed a meniscus that was slightly thicker. The instructions say keep it thin and this is why, too thick and it pops off. I’ll grind the bevel on this side so no harm done

The eagle eyed will see where I tested hardness with a file, there was still some decarb so it bit at first but then proceeded to skate. By the time I’ve got rid of the decarb this side will probably be as clean as the other.

 

[--Tom--]

Bit more progress today

knocked up a super fancy grinding jig by sawing off a piece of wood at 30 degrees and knocking in two nails to rest the blade against

Then set to grinding in the bevels with a 60 grit belt, frequently dipping in water to avoid any softening from the heat generated

Once the main bevel was in an extra nail was added to the jig to support the blade for the side bevels

Progress was quite quick, and produced a soggy ball of wire wool. Side bevels met the narrower part of the blade nicely

the fancy jig kept everything nice and square

All that was left then was a quick hone, deburr the back and refit into the plane. The extra length means I have to take the nose off to fit the iron, but other than that it fitted nicely.
And..... it works! The depth adjustment is pretty nice too with the tight fit on the adjuster there’s virtually no backlash.
As proof here’s a pic with a fresh end grain shaving from 3x2

Thin enough to read through

Overall pretty pleased. The plane has gone from being unusable to something capable of taking nice fine shavings. It feels nice in use as well, can see why I bought it in the first place.