Hollow grinding plow plane irons?

[Tim Best]

I recently picked up a good user grade Record 050 combination plane. While the plane body is good shape and complete, the straight plow cutters need some serious attention. All seem to have been freehand sharpened by previous users/owners. Most are skewed with a wide variety of bevel angles. This is particularly true of the smaller irons. I have recently begun hollow grinding chisels and plane irons and was wondering if plow plane cutters can be hollow ground and then honed on water stones. Would it better (less risky?) to regrind the bevels with sandpaper using an Eclipse style jig and then hone on the stones? My first thought was that plow plane irons would be very similar to chisels, but I thought I would appeal to the collective for thoughts/advice before I jump in.

The best I can tell the 050 is circa 1950s with the original tungsten steel cutters.

Thanks,

Tim

[lowell holmes]

There is a lot of metal in plow plane iron. If it were me, I would try it on one iron. If you do not like the results, you can take back to flat grind. I do think hollow grind is good on chisels, but I do not see the need to do it on a plow plane.

[Jim Koepke]

That is an interesting question Tim. All of my plow plane blades have a flat grind but that is because my powered sharpening system is a disk instead of a wheel.

A hollow grind on plane blades doesn't seem to be a problem for other bevel down plane users. A hollow grind does make it easier to free hand sharpen a blade.

jtk

[Derek Cohen]

All my plough plane blades are hollow ground at 35 degrees. These are free hand honed directly on the hollow grind.

Hollow grinding does not weaken the edge. I use an 8” CBN wheel.

Regards from Perth

Derek

[justin sherriff]

What I like to do to reset a edge is use a cheap eclipse gude but I use it on my belt sander. Then I put a small 2nd bevel on with my water stones. I do not have a grinder.
The wood does not care what is going on much past the edge. Flat grind 1 hollow 1, I bet you will not see any difrence.

[Jim Matthews]

Remember to relieve the sides so they are also sharp.

Plow blades cut three faces.

[Tim Best]

Lowell, Jim K., Derek, Justin, and Jim M.,

Thanks for the advice.

Derek: You mention hollow grinding to 35 degrees. Why do you go to 35? Just curious about your thought process regarding that angle.

Jim M.: I understand that plow blades cut on three sides. How do you normally relieve the sides?

Thanks again for the tips.

Tim

[Tom M King]

I like the Record multi-plane blades, and use them, as first choice, in my Stanley 55's. For the sides, I just hold the iron on edge, on the edges of the stones. I hone all small cutters with the stone sitting on edge, just because it seems like it would be unnecessarily small wear area on a stone face. Mine are flat ground, and honed, as are all my other types of irons. The shape of the bevel shouldn't matter.

[Jim Koepke]

How do you normally relieve the sides?

Hold the full blade on its edge an hone it by moving it back and forth lengthwise on your favorite sharpening medium. It doesn't have to be an edge fit for paring. It also should be free of nicks or rounded over areas.

The side bevels on plow plane blades and other combination plane blades can be honed to the point of cutting. This can be the cause of a rabbet/rebate plane 'walking' if the blade is too proud of the side.

One reason (main reason?) for a side bevel is for clearance (relief angle). A square side to the blade would cause the blade to chew up the sides of the cut or to jam. The side bevels alleviate this problem.

jtk

[Jim Koepke]

In an old thread > https://sawmillcreek.org/showthread.php?242156 < the 10th post has an image of one of my molding plane blades having the edge bevel being honed:

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The side bevel doesn't need to be worked to as fine of grits as the cutting edge.

jtk

[steven c newman]

The ones I have with the Stanley 45....simple 30 degree bevel for the cutting edges....they do have a slight bevel on the sides. Without that side bevels....cutter WILL bind in the cut, just the same way as putting the sliding skate even with the outside edge of the cutter's front edge. Sliding skate needs to be like the main stock...even with the back of the cutter, so the outside corner has a bit of room to work in.

Later today, I need to plow a few 5/16" wide grooves, to house a plywood panel.....will post a few photos of mine after that.....including setting the plane up.....

[Tim Best]

Steven,

Thanks. Looking forward to the post.

[Derek Cohen]

...

Derek: You mention hollow grinding to 35 degrees. Why do you go to 35? Just curious about your thought process regarding that angle.
.....Tim

Tim, 35 degrees is the widely recommended bevel angle. Stanley, Record, etc ... even Paul Sellers ... recommend 35 degrees for the extra edge retention. You could get away with 30 degrees.

One addition is a 10-15 degree back bevel for beading blades, when used in a combination plane in interlocked wood.

Regards from Perth

Derek

[steven c newman]

Kind of hard to hold a cutter, and take a photo at the same time....plywood panel matched a #14 cutter..
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Then set up the stanley 45...
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Cutter has a single flat bevel, at 30 degrees...corners of the iron go past the out side of the skates.
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I get the fence close...then micro-adjust to locate where the groove will be..
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Start at the far end, and work your way back....then a test fit..
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On to the next groove...:D

[James Pallas]

I flat grind on all small sizes, below 1/2” on chisels and irons. I try to keep them at 30 to 35 degrees. I will hollow grind the others and then hand sharpen. I don’t know if it makes much difference but on those small tools they are subject to a lot of pressure when put to work. A 35 degree hollow grind sounds reasonable to leave some back up for a narrow edge tool.

[steven c newman]

Hmmm..got to looking...have a couple cutters, still with the original Stanley factory grind....because I haven't needed them....and, other than cleaning off rust...
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Used my bevel angle checker ( from Veritas, no less)
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Slide a blade in, whichever degree setting fits best..
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Says 30 degrees. Factory grind.
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Sides angle just a slight bit, to provide clearance....When I place both bits side by side so one edge is touching...other faces have a paper thin gap between the two cutters..
As for setting up to do a groove...
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A #14 cutter..after ploughing 4 grooves at 3/8" depth....and hitting a few knots along the way....usually after I've got a good start and just getting halfway to depth...usual...
The #17 and the #24 haven't been used....yet. Been using a #12 a lot....same bevel set ups. No, the bead cutter does not have any "back bevel" and likely will never need one.

[Jim Matthews]

Jim M.: I understand that plow blades cut on three sides. How do you normally relieve the sides?

Tim

I use little diamond hone "paddles" after a quick grind on my coarse India stone.

As others mention, it needn't be sharp enough to cut paper.

FYI - if I'm plowing grooves, my bench knife is used to score the sides as I go. If I planned ahead, the groove is the same width as one of my mortice chisels.

I "drag" one backwards with the grain to clean up the sidewalls of the groove.

I use a dedicated Dado plane or saw/chisel combo cutting across grain.

See Derek Cohen's invaluable series on basic skills for a demonstration.

https://inthewoodshop.com/Furniture/HarlequinsidetableFine%20dados.html

[steven c newman]

I know of a couple better videos out there.....


Keep in mind...when you "sharpen the sides" you will also be CHANGING the cutter's width.....There is one cutter in the set I got with the Type 20, that will not sit into the groove on the plane, without tacking side to side. Someone had taken the sides and tried to remove the side bevel through "sharpening". It will either contact the pin at the top, or, will sit where it needs to at the skate.


Some like to "sharpen" the inside of a profile on the bead cutters....then wonder or complain the bead cutter either no longer cuts the desired shape of the bead, or it now cuts too deep.

Sides on the OEM Stanley cutters are already "relieved" on the sides, comes with the side bevels from the factory. IF you get any without the side bevels, they were sharpened..wrong. Just act like the cutter is a chisel, and just flatten the "back" of the cutter. And leave the side bevels alone.

There is a fellow named Mitch Peacock ( "easy-peasey") and one named Chris (aka Mosquito) on youtube the OP might look at. Both for sharpening, and set up, and using the Stanley 45.

These planes are a bit different than a regular plane. The cutter sits in a fixed "groove", milled into the frame, and has no adjustment like moving a frog for a tighter mouth....also, that groove matches the side bevel of the cutter, so the cutter will sit all the way into the groove. Change the side bevel on the cutter, and the cutter will not sit securely down in the groove, and will twist a bit, enough to cause a bit of chatter.

The only time I've had to use a chisel in a groove..
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Is when I find a knot in the groove. Then I cut/chop it out, until it is deep enough for the bottom of the groove
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So the groove can be completed. I size the width of a groove to match what will be going in it, and do a test fit as I go..
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5/16" thick plywood.....as opposed to the 1/4"/5mm stuff I normally use . Went from using the #12 cutter up to the #14 cutter. I held the cutter to the edge of the board, to make sure it was the right size, before I installed it in the plane.....is very hard to "widen" the groove, AND keep it centered.

Getting a bit wordy...anyway....take all the info in this post, throw it into a "blender" and see what the mix is like.....be sure to install a bs filter, and throw out any sales pitches....

[steven c newman]

Any of the above answer the question?

Just wait, there is also Match Plane cutters, to make a Tongue & Groove joint. There are another pair of cutters (mirror images of each other) that allow window sashes to be made...

Straight edge cutters, not just for grooves, but can be set up to make a dado of any width you might want to cut, or, cut a rebate along the edge of a board...up to just over an inch wide.

I haven't tried it out, yet..but there is a slitter on the side. I use its depth stop to support the back end of the plane, once the front one is beyond the front depth stop's reach on the board, like at the end of the board. The slitter can be used to slice off thin strips from the edge of a board.

Fun part, is when you "need" to sharpen the spurs....I've been using a Dremel on the bevel....either a sanding drum, or a stone cutter/grinding cutter. Pair of visegrips needle nosed pliers to hold the spurs. then a light rub on the back to remove any burrs. Not too much, as the cutting edge of the spur needs to be flush with the edge of the skate...

[Tim Best]

HI Steven,

Thanks for sticking with the thread and thanks to everyone who chimed in with the advice. I did not get as much shop time as I hope for at the start of the weekend. (My wife was promised a new potting bench about year ago and I had to make good on that promise.)Then I was distracted by some dovetails. (That is a completely different story.) Alas, I did steal a couple hours this evening and I made a little progress. Several of the cutters had been sharpened by previous owners with the 1/4" and 5/16" the most heavily used and sharpened. The 1/4" was skewed well out square and honed to something in in between 20 and 25 degrees. The skewed cutter made life very unpleasant during the test run. The 5/16" was in similar shape but it had been honed to ~30*. Those are the two I worked with this evening. They were both quite dull (although I am still trying to figure out what sharp is, even I could tell they were not sharp. I put them in some clear SYP (yes I know pine is not an ideal material, but it is inexpensive here and it makes me cringe less when I mess up a piece of SYP instead of a piece of Maple or White Oak. Since both cutters were in a similar state, I decided to hollow grind one and flat grind the other with PSA on a granite block using an eclipse-style guide. Even though I had previously modify the jig, the small 1/4"cutter did not want to stay firmly seated in the guide. Also, it was a bear to regrind the bevel to 35* on that cutter. Long story short, the flat grind at 35* worked well. I did notice that cutter wanted to occasionally lift up as it was cutting. For some reason it just would not seat properly in the groove. (I will address that issue in the coming days.)

I hollow ground the 5/16* and freehand honed it to 35*. It also worked well, really well in fact. While both methods certainly worked, I think I will stick with the hollow grind because it sped up the process and the resulting hollow gave me a nice platform to freehand hone of off and I much prefer the simplicity of freehand honing.

I also took a few minutes to tinker with the beading irons. (Truth be told, I bought the Record 050 because it gave me the ability to cut a wide range of beads and I like using beads whenever I can work them into a project. I notice in one of your previous posts that you do not hone the inside of the bead and work on the back. Is that correct? How to you address the leading edge of the bead cutter. Surely it will dull over time or, more likely, hit an unknown knot. I will post some before and after pics in the next day or so about the straight cutters I have hollow grand and honed to 35*

Thanks again to everyone

[steven c newman]

The "back" of the cutters do the cutting, the bevel is more for clearance, as these are used bevel down. I flatten the backs of the bead cutters, and hone just the quirks on either side of the profile....trying to keep them even with each other, and the edges straight...no skew, no back bevel. I tend to keep the factory bevel on mine. Plane is a Stanley #45, Type 20. Made at Roxton Pond, QUE. CAN. and is stamped with the SW logo.

Have yet to need a grinder on any of the 24 cutters that came with the plane. Hard to do a hollow grind without that grinder.

[Jim Koepke]

How to you address the leading edge of the bead cutter. Surely it will dull over time or, more likely, hit an unknown knot.

There are slipstones in oilstones, diamond stones and in water stones. Some folks wrap abrasive paper around a dowel.

Here is a good tutorial on sharpening beading and other molding blades > https://blog.lostartpress.com/2017/02/16/how-to-sharpen-moulding-plane-cutters/

An old post of mine also provides some information on complex shaped blades > https://sawmillcreek.org/showthread.php?242156

jtk

[Tim Best]

Thanks for the reply, Jim. On the few bead cutters that I’ve touched up, I’ve used sandpaper and dowel rods (mostly because I already have both in the shop.) My curiosity is that Steven never touches the bead cutter bevel while sharpening.

[steven c newman]

I hone the flat back of the bead cutters, AND the quirk cutters on each side of the bead profile....no need to mess with the bead's profile area....do that enough, and you will change the shape of it....