Question on "nicker" iron for wooden dado plane

[Frederick Skelly]

Cleaned up and sharpened the wooden dado plane I found in an antique store. Works well enough - especially for the $15 I paid. The blade is 1/4" wide and the nicker iron is 5/16" wide. The dado ends up closer to the nicker size (5/16"). The nicker iron sits in a mortise a few inches ahead of the blade and is held in place with a wedge. The nicker blade is shaped like a spade drill bit without the point in the center.

1) Does this sound normal? I would have expected the nicker size to match the blade width.

2) Id really prefer to cut 1/4" wide dados to match the blade. Im relectant to simply squeeze the nicker points closer together. Brittle old metal, alignment with blade, etc are concerns. Am I right to be wary of doing this?

3) Are there places I can go to buy replacement nicker blades (old or new ones)?

Thanks guys!
Fred

[Darrell LaRue]

Hi Fred

1) Normal. My dado planes have the nickers very slightly wider than the irons. Maybe not as much as yours, but wider certainly.

2) don't squeeze the nicker iron tips. Mine are made so that they are the same outside width for a ways up the sides. So to narrow them you should hone them down on your favourite sharpening medium.

3) Metal Supermarket sells nicker blade blanks, in the form of O1 flat ground stock. All you need to do is hacksaw and file them to shape. Heat treat if you are planning on heavy use, otherwise they will be fine as-is for occasional use.

Darrell
you sure got yer money's worth here, SIX cents worth of advice ;)

[Frederick Skelly]

Hi Fred

1) Normal. My dado planes have the nickers very slightly wider than the irons. Maybe not as much as yours, but wider certainly.

2) don't squeeze the nicker iron tips. Mine are made so that they are the same outside width for a ways up the sides. So to narrow them you should hone them down on your favourite sharpening medium.

3) Metal Supermarket sells nicker blade blanks, in the form of O1 flat ground stock. All you need to do is hacksaw and file them to shape. Heat treat if you are planning on heavy use, otherwise they will be fine as-is for occasional use.

Darrell
you sure got yer money's worth here, SIX cents worth of advice ;)

Thanks very much Darrell! I appreciate it.
Fred

[Jim Matthews]

If you hone the sides of the nicker iron, and bevel the cutting edges you might get close
to the nominal 1/4" dimension you're after.

That said - I would assert the following SWAG -

That gap isn't slop, it's intentional. It either leaves room for assembly of drawer bottoms,
which were traditionally planed to fit the opening, or it gives room for the mating piece
to be fitted with glue.

If you're making lock rabbet joints for drawer fronts, it won't matter if the mating pieces
are cut with the same plane.

I dunno if you're already up to speed on using a dado plane, but somebody clued me in -
start scoring the groove you intend to cut by drawing the knickers backwards.

I can't cut straight without a batten, either.

[Derek Cohen]

Hi Fred

A little trial-and-error sharpening is needed.

Firstly, recognise that the knickers are to prevent tearout by cutting cross-grain fibres ahead of the blade. The knickers need to slice in line with the edge of the blade. So, sharpen the knickers (just polish the bevels for now) and the blade, put it all together, and try it out.

Now, does the plane leave tearout on either side of the blade? Assuming that you have set the blade/knickers up in as coplanar a manner as possible, then if there is tearout, either the blade is wider than the knickers, or the knickers are wider (one or both) than the blade.

If the former, then the blade needs to be reduced in width. If the latter, then the knicker(s) need to be adjusted to the edge of the blade.

Once set up and cutting correctly, then measure the width of the dado. Is it 1/4" as you desire?

Let's assume that the dado is a smidgeon over the 1/4" - does this really matter? Probably not. If it is as much as 1/16" over size, you can try reducing the knicker width by lapping the outsides of the knicker to reduce its total width (remember to split the difference between sides). But do this only when you are certain that it is too wide. I would sharpen and test it out as is first. I cannot imagine that a vintage plane has made it this far in its life without having worked appropriately at some point for some one.

Regards from Perth

Derek

[Frederick Skelly]

If you hone the sides of the nicker iron, and bevel the cutting edges you might get close
to the nominal 1/4" dimension you're after.

That said - I would assert the following SWAG -

That gap isn't slop, it's intentional. It either leaves room for assembly of drawer bottoms,
which were traditionally planed to fit the opening, or it gives room for the mating piece
to be fitted with glue.

If you're making lock rabbet joints for drawer fronts, it won't matter if the mating pieces
are cut with the same plane.

I dunno if you're already up to speed on using a dado plane, but somebody clued me in -
start scoring the groove you intend to cut by drawing the knickers backwards.

I can't cut straight without a batten, either.

Thanks Jim! I need to try both that backward draw and the batten. I think both will help, as I was just freehanding last night.
Fred

[Frederick Skelly]

Hi Fred

A little trial-and-error sharpening is needed.

Firstly, recognise that the knickers are to prevent tearout by cutting cross-grain fibres ahead of the blade. The knickers need to slice in line with the edge of the blade. So, sharpen the knickers (just polish the bevels for now) and the blade, put it all together, and try it out.

Now, does the plane leave tearout on either side of the blade? Assuming that you have set the blade/knickers up in as coplanar a manner as possible, then if there is tearout, either the blade is wider than the knickers, or the knickers are wider (one or both) than the blade.

If the former, then the blade needs to be reduced in width. If the latter, then the knicker(s) need to be adjusted to the edge of the blade.

Once set up and cutting correctly, then measure the width of the dado. Is it 1/4" as you desire?

Let's assume that the dado is a smidgeon over the 1/4" - does this really matter? Probably not. If it is as much as 1/16" over size, you can try reducing the knicker width by lapping the outsides of the knicker to reduce its total width (remember to split the difference between sides). But do this only when you are certain that it is too wide. I would sharpen and test it out as is first. I cannot imagine that a vintage plane has made it this far in its life without having worked appropriately at some point for some one.

Regards from Perth

Derek

Thank you Derek! I'll try this tuning and see if I can get there. I appreciate your advice.
Fred

[Warren Mickley]

The nickers have to be wider than the cutting iron. If they are very close to the same width, the alignment has to be perfect to avoid trouble. The nickers also have to be wider than the body of the plane. If they are too close in width there is danger of the plane stock rubbing the walls of the dado, which gives problems also. You should not narrow the nicker blade unless you would consider narrowing the stock of the plane also. If there is 1/32 or less between the nicker and the edge of the blade on each side, you should have no trouble.

5/16 is a common size for a dado plane. In historic times, rather than have a set of different size planes, they often got a 5/16 and made two cuts on the board, one for each edge of the dado. So for 7/8 they would make two 5/16 cuts and chisel out the 1/4 in the middle. This enables one to make a dado 7/16 or 27/32 or whatever with one tool. If you want a 1/4 dado, I would get another plane.

[Jim Matthews]

I think both will help, as I was just freehanding last night. Fred

I suspected as much.
I can't cut straight, for the first few passes.

I'm forever digging in on one side, or the other.
A plane like this with three cutting edges will try to
follow grain, along a path with least resistance.

FWIW - I use a batten now, and just nail it on.
I draw the dado plane backwards, to mark where the knickers
will track. I score those marks with a knife, as a sort of 'starter'.

I have mine set to cut really fine shavings, on the order of 4 thousandths.

I don't need to go fast - but I do want straight, and clean side walls.

[Frederick Skelly]

The nickers have to be wider than the cutting iron. If they are very close to the same width, the alignment has to be perfect to avoid trouble. The nickers also have to be wider than the body of the plane. If they are too close in width there is danger of the plane stock rubbing the walls of the dado, which gives problems also. You should not narrow the nicker blade unless you would consider narrowing the stock of the plane also. If there is 1/32 or less between the nicker and the edge of the blade on each side, you should have no trouble.

5/16 is a common size for a dado plane. In historic times, rather than have a set of different size planes, they often got a 5/16 and made two cuts on the board, one for each edge of the dado. So for 7/8 they would make two 5/16 cuts and chisel out the 1/4 in the middle. This enables one to make a dado 7/16 or 27/32 or whatever with one tool. If you want a 1/4 dado, I would get another plane.

Thank you Warren! I didnt know any of that. Also, it never crossed my mind to make two cuts to get a wider dado. (DOH!) I was considering also getting a 3/4" but now I see that I should be able to learn to use one tool.

Fred

[Frederick Skelly]

I suspected as much.
I can't cut straight, for the first few passes.

I'm forever digging in on one side, or the other.
A plane like this with three cutting edges will try to
follow grain, along a path with least resistance.

FWIW - I use a batten now, and just nail it on.
I draw the dado plane backwards, to mark where the knickers
will track. I score those marks with a knife, as a sort of 'starter'.

I have mine set to cut really fine shavings, on the order of 4 thousandths.

I don't need to go fast - but I do want straight, and clean side walls.

Thanks Jim! I'll try making some thin shavings tonight if I can squeeze in some shop time.
Fred

[Frederick Skelly]

For several days Ive been trying to bring this old 5/16" dado plane back to life. Here's what I think Ive learned through the process to hopefully help the next hand tool newbie like me. Please chime in if you have additional ideas or corrections. These are my thoughts, based on purely trial, error and the kind advice contained earlier in this thread.
1. Using a batten really helped keep the blade between the score marks and to get a nice, straight perpendicular cut.
2. Drawing the plane backward before making the first pass is a must. (Or else scribe your lines to cut the fibers.)
3. It seems like the nickers cut on the backward stroke, NOT the push stroke. I think thats why the nickers are angled so that the points face the toe. So it's cutting like a knife when you draw it back.
4. Dont bust your hump sharpening the nickers. Polishing the bevel seems to be enough.
5. Dont set the nickers to score too deeply - just a light cut is enough if you are taking a thin shaving. (If you try to score too deeply, your cuts will be very ragged and ugly. Then you will drive yourself bonkers trying to find a way to sharpen the nickers more than they really need to be. Then you will use up 1/4" of your 150 yr old plane's nicker and be very very embarrassed. DAMHIKT. Just take my word for it and set your nickers to score lightly, OK?)
6. Sure wish I could suggest a book that taught newbies how to tune and use one of these. Anyone know of one?
7. A well adjusted dado plane is a lovely tool to use. Nice, smooth sides and bottom. Well worth the $15 I paid. :)

Thanks to all of you for your help and advice folks!
Fred

[Jim Matthews]

I would suggest that this thread should be "sticky".

This particular tool is finnicky, but can do things
a router plane can't without lots of extra steps.

These things cut fast, and with a depth stop
repeatedly to the same dimensions.

[Chris Hachet]

Agree with the sticky part. I do not currently own a dado plane, need to add one to my inventory.

[Frederick Skelly]

A couple more observations, just for the archives.
3a. I still think the nickers cut on the backward (pull) stroke. But I did what Dunbar shows in his book and rounded them so when I push there is a bit less resistance.
5a. Set your nickers about a hair deeper than your cutter. If it isnt, then you arent really getting all the fibers cut and tearout may result.
5b. For me, setting the nickers to a depth of 1/32" seems to work well. Make sure the cutter is taking a very fine shaving that is less than that.
5c. Make sure the cutter does not overlap the nickers. Look down the sole and make sure the cutter aligns between the "V" of the nickers. When it overlapped in the horizontal (side to side) or vertical, I got tearout. By ertical, I mean that you can set the nickers to cut so deep that their V shape overlaps the cutter too much.
6a. I found a book. It tells you how to shape the cutter and nickers in excellent detail. Its called RESTORING, TUNING AND USING CLASSIC WOODWORKING TOOLS, by Mike Dunbar. My only beef is that he doesnt talk enough about the fine points of adjusting things after the "restore" part. But his description of how to shape the nicker was well worth the $25 I paid for the book.
8. Jim Matthews really nailed it when he said these planes are "finicky". Mine was setup perfectly when I wrote that enthusiastic last post. Then it got out of adjustment and I spent parts of 2 evenings trying to find the sweetspot again. I think thats partly because I didnt know what it was supposed to look like, so I had to play trial and error games. But I guess my message for newbies is "be patient - it will come".
9. I missed the fact that the cutter is supposed to be skewed. Mine is only skewed about 3*, but it made a difference when I corrected that. Dunbar talks about how to judge the amount of skew needed in his book.
10. As others said - the cutter, the sides of sole and those doggone nickers MUST all be coplanar. Correcting this was another noticeable improvement.
11. Put a straight edge on the sole of your plane. Mine was not flat and needed jointing. Another small improvement.
12. Lie Neilson sells annealed blanks of O1 steel for molding planes. Im not certain - havent called to verify - but they LOOK like you could use them to fabricate a new nicker or maybe even a cutter for a dado plane. Youd have to harden the cutter after shaping, of course. I dont yet know if one needs to harden the nickers. Jury is still out.

Thats all for now. More if and when I learn anything. Once again, these are my observations and Im "planing by braile", trying to figure out how to setup and use this tool by trial/error and what little I can find online or in books. If you know better or more than I do about dado planes (which wouldnt be very hard) PLEASE correct me so the right info gets into the archives.

Fred