Thread: Ham Knife - other uses

For those of us who haven't been keeping up, a picture of your ham knife might help in coming up with suggestions.

Ham Knife and pictures of mortise sequence

mortise tools.jpgIMG_5667.jpgIMG_5668.jpgIMG_5671.jpgIMG_5673 2.jpgIMG_5674 2.jpg

In a mortise the pillar of of timber can pe prised out with a bolt. The process is quite quick.

Martin, from your description it sounds like you have re-invented the veneer saw:

Veneer saw b.jpg

The edge is sharpened like a knife (usually on one side only to allow it to be used against a fence) and the teeth have no set.

They've been around for a year or two.....

Cheers,

Originally Posted by IanW

Veneer saw b.jpg

The edge is sharpened like a knife (usually on one side only to allow it to be used against a fence) and the teeth have no set.

I'm a respectfully disagreeing with that Ian. Even though you have built 100% (edit 99.9%) more saws than I have.
The veneer saws Ive used came sharpened like a rip saw with no set to the teeth and negative rake. The file passed across the teeth at 90 degrees and a square edge. And they cut sliced veneer beautifully that way. There is no fine cutting edge to them. Bevelled. If that's what you meant.
Well not the couple Ive seen. One I bought . One I made and another one guy at work owned.

Which is what your saw looks to be from this angle.

Ian,

Using the "ham knife" like a chisel. But unlike a chisel as it has a double bevel the frictional resistance to deep penetration is is significantly reduced. By deep i mean say 25mm to 30mm deep parallel to the grain. I could get a chisel in the this deep without a press and the timer would be very compressed on side.

The round blade also allows rocking to withdraw or deliberately induce slitting.

Using it for sometime mostly for making mortises but a have a couple of narrower versions for small details and cut across the grain- ie dovetail waste.

I doubt I have invented anything - someone at some stage would have beed using a tool like this similarly- but as yet I have not found suitable "pre existing" tool name. For the main use Twybil is is nearest tool I currently know of as ir cuts the parallel to the grain as well

Regards

Thanks for this info on veneer saws- I know they exist but have never tried one.

Originally Posted by auscab

I'm a respectfully disagreeing with that Ian. Even though you have built 100% (edit 99.9%) more saws than I have.
The veneer saws Ive used came sharpened like a rip saw with no set to the teeth and negative rake. The file passed across the teeth at 90 degrees and a square edge. And they cut sliced veneer beautifully that way. There is no fine cutting edge to them. Bevelled. If that's what you meant.
Well not the couple Ive seen. One I bought . One I made and another one guy at work owned.

Which is what your saw looks to be from this angle.

Rob, I think there's a bit of variation in how veneer saws are sharpened, maybe regional differences, or simply user preference? I copied mine from an article I saw somewhere, many moons ago, but can't remember where it was now, but that bloke put a bevel on his saw so I just followed suit. The rake angle is negative, varying from quite a bit to much less as the saw is pulled and rotated. I cut the teeth by eye and it was easier to just keep the file at a constant angle to the curve (more or less!) than try to maintain a constant rake angle wrt the radius of the edge. It works fine & cuts very quickly for about two thicknesses of veneer (the most I've ever needed to cut), but the bevelled edge doesn't allow for a deep cut, it slows down very rapidly after a few mm. I think not bevelling the edge would allow a deeper cut, but maybe not as fast? Dunno, I made it for a particular job (only took a half hour, much quicker than going out to buy one ) & have hardly used it since.

Neither type would be practical for cutting 25mm deep, so I'll be interested to learn more about Martin's 'ham knife".

You would have done far more veneering than I have so I'll bow to far greater experirnce. Virtually all of the veneering I've done was making speaker boxes, hardly high -end work!

Cheers,

Ian

While it is cutting - the knife is hammered in, to reach that depth.

Originally Posted by IanW

Rob, I think there's a bit of variation in how veneer saws are sharpened, maybe regional differences, or simply user preference? I copied mine from an article I saw somewhere, many moons ago, but can't remember where it was now, but that bloke put a bevel on his saw so I just followed suit.

Your right Ian . It is being described to sharpen the veneer saw that way .

How to Sharpen a Veneer Saw - FineWoodworking

I use mine sharpened the other way and was always impressed at how good it cuts. And the cutting is not affected by grain direction. They Beat trying to cut veneer with scissors or a straight edge and sharp blade by a long long way.

Rob

Originally Posted by auscab

Your right Ian . It is being described to sharpen the veneer saw that way .

How to Sharpen a Veneer Saw - FineWoodworking

I use mine sharpened the other way and was always impressed at how good it cuts. And the cutting is not affected by grain direction. They Beat trying to cut veneer with scissors or a straight edge and sharp blade by a long long way.

Rob

Rob, just different traditions I expect, & what works, works, so no need to change your habits at this late stage of your career...

And yep, spot on! It was precisely trying to cut some Qld Walnut veneer with a craft knife and having it split ouy in front of the knife in directions I didn't want it to split that sent me looking for a better way. The better way is definitely a veneer saw, however it's sharpened.....

Cheers,

Originally Posted by MartinCH

Ian

While it is cutting - the knife is hammered in, to reach that depth.

OK, I'm with you now Martin. So it's more like the "kerfing" tool that got a bit of air time recently. Derek made his in the form of a chisel, but the ones I've seen are usually more like this:

Kerfing tool 1.jpg

When driving them down into end-grain like in the pic they actually work better if the edge is left square, not sharpened like a knife. I made one years ago when I first read about the technique (promoted by Tage Frid in an early FWW mag.). Either I didn't read the article properly (highly likely!) or he didn't emphasise not to sharpen it, but that's what I did. That made it a very effective tool for splitting out & ruining the first set of drawer fronts I tried it on, so I ditched that idea. Recently, I made the above tool with a little more knowledge & experience behind me, & whaddya know? It works & works very well.

I could have been using one for 30 plus years if I'd only read the article properly....

Cheers,

Ian

In this case, the usage is drive down between two holes drilled for a mortise. The aim is drive deep and the double bevel can help in this case. The holes effectively stop splitting.
I have use a blunt version as wel, but generally the ham knife.
Leaves a pillar of timber which can be levered out. Typically used a bolt same size as the hole to do this. I can knock out mortises this way in 30 seconds or so.



Since I was messing with the knife I was looking at other tasked that need a deep driving tool - removing waste is application
ill check how well it curved edge cut veneer.

Note
Blunt tools for wood is an ancient concept- Blunt nails to stop splitting have been used since the nail was invented. There are a couple trick that can be applied to reduce splitting

From here - and I'll grant that there's an entire Pacific Ocean between you and me, so I may be missing some fine detail - your tool looks like a stiff putty knife with an edge honed on it (and, in fact, one of the several variants of putty knives is one thick enough for a bevel, that commonly comes with a bevel). Yours has some camber to the edge, but otherwise looks like the putty knife just described. I'd never thought of one of those as a wooddorking tool, but sure: if it works, it's a tool.

Some years ago I had a need for a really thin chisel, I mean really thin, to pare the sides of some narrow slots to a precise fit. I'd kept a couple of old steel tablesaw blades, long after I'd switched to TCT blades, which I was slowly cutting up for things like marking knife blades & so forth. The plate is just over 1/16" thick in old money & tempered to a hardness that is tough but file-able, as you'd expect. The wood I needed to pare was relatively soft, & I reckoned the saw plate would get the job done, so I made a small chisel about 20mm wide and sharpened it up. It worked remarkably well on that job, so I pulled off the crude bit of scrap I'd whittled for a handle & put a more workmanlike one on it. I've used it many times since for paring in tight spots. It's definitely not a chisel for beating into hard wood though.

Even when paring relatively soft woods I need to give it a quick hone every few minutes. I reckon that if the business end was several Rockwell points harder, it would be an excellent little gadget, but I've been reluctant to try hardening it because I have visions of it warping terribly, or creating a brittle point between hardened & original steel or something worse. But I still have plenty of saw plate, so I ought to take courage & just try it & see what happens....

Cheers,