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View Full Version : Need advise on making a honeycomb de-capping knife



psfred
05-15-2013, 09:35 PM
I hope this isn't too far afield as a de-capping knife isn't really a kitchen knife, per se, but more or less fits the description. I've been looking for a while and all I can find is serrated "you never need to sharpen" (ha!) blades or a very few European hand-crafted knives with plain blades but riveted to the offset handle.

Before I ask specific questions, let me describe the knife - it has an offset handle parallel to the blade (to keep the operators hand out of the honey), a flat blade about 10 inches long, it's sharpened on both sides so you can cut up or down, and is used to slice the cappings off filled honeycomb which is contained inside a wooden frame. I've seen a number of different designs, but typically they are an inch to 2 inches wide with about an inch and a quarter offset. Some have square tips, but the one I've been borrowing has a rounded tip.

It is used to slice off the capping and very top of the cells of honeycomb to permit centrifugal extraction of the honey. Normally used from bottom to top of the frame, with the frame held at a double angle to allow the cappings and honey to run off the blade into a container to drain the honey out. While the comb is fairly soft as things go, it's also very easy to crush, and the objective it is to shave off the minimum amount of cell wall to make it easier for the bees to fix it and re-fill it with honey. Sharp cuts also mean less wax in the honey, faster filtering, and happier consumers.

Questions:

Since this needs to be razor sharp to cut the wax comb without crushing it, what's the best material? We can get just about any steel we want through MSC. I'm thinking carbon steel (1095 probably) about 1/16" thick, but am open to suggestions.

What's the best way to bend the offset? Forge? I have access to a good blacksmith and forge.

Sharpening angle? I'm thinking single bevel and fairly shallow -- this is a slicing knife in fairly soft material, no need to worry about chips unless someone runs it into a nail at the end of the frame or something.

Heat treat? Needs to be hardened and tempered, again I have access to a coke fired forge so heat is no problem.

Someday I'll probably cough up $150 for a heated knife for this job, but that's a way off, I think, about the same time I buy an $800 extractor instead of borrowing one.

Thanks!

Peter

sachem allison
05-16-2013, 02:45 AM
I was just going to say by the time you get the materials, forgings, and finished it will cost you about the same as buying a heat knife. Try ebay you might save some dough.

sachem allison
05-16-2013, 02:53 AM
http://www.ebay.com/itm/ELECTRIC-UNCAPPING-DECAPPING-KNIFE-BEEKEEPING-EQUIPMENT-BEE-HONEY-APICULTURE-12V-/380550239848?pt=LH_DefaultDomain_0&hash=item589a8fd668

and this one.

http://www.ebay.com/itm/Stainless-Steel-Uncapping-Cold-KNIFE-extracting-10-250mm-Bee-Keeping-/380640288153?pt=LH_DefaultDomain_0&hash=item589feddd99

skiajl6297
05-16-2013, 09:01 AM
OP - out of curiosity, where are you located? Best of luck!

psfred
05-16-2013, 08:18 PM
Evansville, Indiana

I seriously doubt an 18 inch piece of carbon steel is going to set me back more than a larger piece of A2 I'm looking at for another project (2.5" x 18" x 1/8" or 3/32", $28 plus shipping), and the rest of it is free except heat treat, and that I can piggyback onto my brother's business (gear making) if necessary.

I'd just take a carbon steel cheapo knife and re-purpose it except that makes it too short for keep frames (9 3/8" wide).

In case you didn't notice, the electric knife references is a 12V model with no thermostat, not a good plan, and the Ukrainian one has a SPOT WELDED blade.

Not a chance! Those knives are sorta like recommending someone go to Walmart for a top quality Japanese knife. A real one is at least $150 and I have absolutely no desire to work with a knife that may fall apart in the middle of an extraction run. Thanks for the thought, though.

Peter

Bill Burke
05-16-2013, 11:09 PM
I personally would start with something like 1/2 inch square 52100 and forge a tang and the forgemy offset for the handle. the do a slight upset at he first bend from the blade. the upset would be to allow material for a bit of reinforcement and still have enough maerial to make the blade wide enough. I would then forge the square bar into the blade shape that I wanted leaving it thick enough to resit warping during the quench. after hardening finish grind. I wouldnt do a full chisel grind instead opting for a heavily biased grind instead. the reason for this is to allow more control over my depth of cut.

Michael Rader
05-16-2013, 11:34 PM
Hey there. How many hives do you have? My wife and I have been raising bees for two years now. Cool. Lost our first hive, so didn't get a chance to collect honey, but this year should be good, as our hive is much stronger now that is survived the wet winter. We were going to just rent a hot-knife and I didn't think about making my own. Hmmm, wish I knew a knifemaker that was into that kind of stuff...

sachem allison
05-16-2013, 11:40 PM
Evansville, Indiana

I seriously doubt an 18 inch piece of carbon steel is going to set me back more than a larger piece of A2 I'm looking at for another project (2.5" x 18" x 1/8" or 3/32", $28 plus shipping), and the rest of it is free except heat treat, and that I can piggyback onto my brother's business (gear making) if necessary.

I'd just take a carbon steel cheapo knife and re-purpose it except that makes it too short for keep frames (9 3/8" wide).

In case you didn't notice, the electric knife references is a 12V model with no thermostat, not a good plan, and the Ukrainian one has a SPOT WELDED blade.

Not a chance! Those knives are sorta like recommending someone go to Walmart for a top quality Japanese knife. A real one is at least $150 and I have absolutely no desire to work with a knife that may fall apart in the middle of an extraction run. Thanks for the thought, though.

Peter

sorry, just trying to help. appreciate the sarcasm though. made my day.

psfred
05-17-2013, 12:39 AM
Michael:

My brother and I currently have four hives, will have more in the next week as we plan to do a couple splits and need to do at least one cutout (two if my brother in Tennessee had a swarm actually move into his house wall rather than just visit for a while). Two of them have at least one shallow super of honey, maybe two, they've been rather busy lately. The third mature hive is suffering from a badly done split earlier and is lagging, but I've not been in to check for a while. No supers on it, so no honey for me anyway.

Bill:

Forging a blade is an option someday, but since this is a very low stress job, what I really need is thin and very very sharp to avoid crushing the comb, it's quite delicate and will be warm (90 F or so hopefully) so the honey comes out better. We will see what happens with thin 1095, it's cheap enough I won't be heartbroken if I make a wall decoration instead of a knife.

There are two reasons I'm thinking chisel edge -- the knife we borrow along with the extractor is sharpened that way, and there is no need to do much to control the depth of cut, if all goes well and the bees behave, the comb is all higher than the wooden frame and the knife is guided by the frame. The knife also needs to be sharp on both sides, it's sometimes necessary to cut both ways to get all the honey uncapped and we have a lefty in the family to boot.

As far as knives for this job, the offset is nice, it keeps your hands out of the honey, but any very sharp knife will work if it is long enough. Not a real issue with shallow frames, but deeps are over 8 inches wide so the cutting edge has to be longer than that.

Sachem allison:

Glad you enjoyed the sarcasm, those knives on eBay are pretty dreadful. The Ukrainian one does not appear to be sharpened, in fact. Even a heated knife should be reasonably sharp.

Peter