Marking Dovetail Pins

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woodbloke

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I've used a variety of knives shown below in the pic to mark out pins from tails - none have been really satisfactory

stuff003.jpg


The small stanley knife has a very pointy profile so that its quite difficult to register it against the side of the tail, added to that it has a double bevel on the blade, so it has to be canted to one side to make it snug at the bottom of the dovetail. The scalpel is similar but worse, its too flimsy and makes such a faint line that its difficult to see it at all. I tried a Jap knife which I backed of on the grinder so that it could mark both sides of the tail; same sort of problem as the other two tho' in addition the hollow grinding on the back of the blade further restricts the accuracy as there's less steel to sit against the tail

Then..... I remembered that lurking in my odds n' sodds box I had a small piece of HSS hacksaw blade so I made a knife as shown; 10 minutes on the grinder.

stuff002.jpg


Its double ended and ground only on one bevel each end so that each side of the tail can be accurately marked. It isn't pointy like the other ones so there is plenty of metal to rest against the side of the tail.....however it is a little bit flexible in use and a trifle small in the hand so then I had some further thoughts and remembered that in the deepest and darkest recesses of the aforementioned box I has a piece of HSS machine hacksaw blade....so I made yet another knife

stuff001.jpg


Again, about 10 mins on the grinder and because its HSS I didn't have too worry unduly about losing the temper on the steel - didn't get it too hot tho'. This one works superbly, ground again only on one bevel at each end and the thickness of the steel means that it don't flex at all.
Its probably worth IMO doing a trawl round your local friendly machine shops to see if you can scrounge some broken machine hacksaw blades because they do make excellent knives. I once worked with a Parnham trained maker who used nothing else as a marking knife having tried all sorts of others; he also used a knife like this to cut veneer using a square block of timber to rest the blade against. Pics a little out of focus, hope explanation helps - Rob
 
Hi Rob

Yes, jigsaw blades make for great marking knives. I have been using them in my most recent design.

I am curious to know how you use your knife? Is the bevel the angled section? How do you exert downward pressure?

Here is a picture of a couple I made recently. One is Jarrah and the other is Tasmanian Blackwood. The blades are 1" long and stiff with just a little flex. They are perfect for getting into skinny dovetails and comfortable to hold (like a pencil).

Markingknives1.jpg


Regards from Perth

Derek
 
Derek - not nearly as posh as your blades, (very nice) but working on the same principal, that of a single bevel. The flat part of the knife is against the tail, bevel outermost and it is held vertically to make the cut. The blade is reversed in the hand to mark the other side of the dovetail - Rob
 
Glad I'm not the only one to struggle with finding a knife that suits me - been meaning to track down some power hacksaw blades for ages now, but TUIT where art thou? :( My problem is I like a point that points downwards (like the top one in your pic of three, Rob), which rules out all the gorgeous spear point varieties like Derek's. Making do with a CK lamb's foot at the mo', but the double bevel isn't ideal and it's a bit chunky for finer pins. Oh well, at least it's a reasonably inexpensive quest to keep me out of mischief :lol:

Cheers, Alf
 
I find that old planer blades make superb knives for marking out dovetails. Just grind to your prefered angle. They take a very keen edge too. Bevel edged chisels are good as you hold the chisel back vertically against the tail and work on either side.
 
I have used lots of things and am still searching for the ideal knife. I have recently treated myself to one of these (it is the small one that he makes).

It works very nicely but I also favour a small (keychain sized) Swiss Army knife.

SmallMarkingKnifeCocobolo.jpg
 
For this interested in building a marking knife along the lines of mine (and Chris' Blue Spruce - the dimensions are very similar), the following pictorial sequence may help.

Bladeshapingsequence2.jpg


I can get two blades out of a long jigsaw blade. I shape both ends, then cut it in half. A tang is cut with a Dremel, and the wooden body is cut and drilled to fit the blade.

Regards from Perth

Derek
 
And Dave at Blue Spruce is a great guy to work with if you have a design different than he offers...

Of course, he's a local-to-me guy :D

Great tools. Take care, Mike
 
BB

I was waiting for that one! :lol:

Regards from Perth

Derek

PS If you look at the very end of that WC thread you will find another of my very wierd marking knives. This one is the wierdest!
 
Opinel penknife for dovetail pins and all other knife marking. Has a very thin and fine pointed blade. And pencil sharpening, bacon sandwich cutting, tater peeling etc. u name it!

Of course that is just so sensible Jacob. But where is the fun if you are not obsessing about an obscure detail? :lol:

Regards from Perth

Derek
 
Mr_Grimsdale":s6ih7e0n said:
Opinel penknife for dovetail pins and all other knife marking. Has a very thin and fine pointed blade. And pencil sharpening, bacon sandwich cutting, tater peeling etc. u name it!

cheers
Jacob

Excellent knives (I have 2) but the point is too rounded to get right to the back of the DT pin.

BugBear
 
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