Sole flattening

[Timothy MacMurtrie]

Just looking for separate thoughts on regular tempered glass being used to flatten the soles of both metal and wooden planes

Thanks

[Jim Koepke]

Before any consideration of what works best for sole flattening one should really be sure the sole is in need of flattening.

It is easy to deform the sole of a plane when trying to flatten its sole. It is a tedious and demanding process.

For a wooden plane a jointer may be a better option for flattening.

Are your planes having problems that indicate the sole is at fault?

Tempered glass can still flex if resting on a non-flat surface.

jtk

[Bill Houghton]

Plate would be better, and the thicker the better (1/2" and up). Talk to a glass shop, preferably one that does a lot of commercial work, and see how often they get suitably sized scrap. But I'm with Jim: do you know your plane(s) is/are out of flat? I've owned multiple planes, and found only one or two on which the sole was enough out of flat to justify spending time on them - and I chose to bypass that by getting rid of them.

In theory, if you're using loose grit on tempered glass, you'd eventually reach the stage at which you broke through the tempered surface and released the tension - an exciting moment.

[Robert Hazelwood]

I have a granite surface plate that is about 5" wide and 18" long and 2" thick, was pretty inexpensive. It works very well for lapping smaller planes like #4s and #5s. I have also lapped a 22" wooden try plane on it, but you have to be careful with technique. It wouldn't work well for a long metal plane- you really want something much longer than the sole length, and granite surface plates start to get expensive quickly above a certain size and would be cumbersome. I've heard that asking a glass shop for a 4' glass shelf (more or less a stock item) is the best way to get a long lap relatively cheaply vs asking for a custom piece of glass.

[Timothy MacMurtrie]

Thanks guys for your answers
My planes are all flat and not in any need of flattening
I’m just thinking of grabbing a few older planes to play with and was just curious as to what experience has taught y’all that y’all have kindly shared and again thank you

[Warren Mickley]

I use a smoothing plane to dress the soles of wooden planes. You want to remove as little material as possible from the sole of the plane. The best way to do this is to check the sole with straightedge and winding sticks and only remove material from the high spots. A smoothing plane is good at taking short controlled shavings from specific areas. A jointer plane is more efficient for flattening when you have some material to burn and you can take full length or nearly full length shavings.

A plane also leaves a smoother surface, slicker and more durable, compared to sand paper or grit.

[Timothy MacMurtrie]

Was your piece of granite custom ordered or was 5”x18” a standard size
Also was it purchased online or locally

[Timothy MacMurtrie]

Agreed.... I was also thinking a scraper might even be ok for small touch ups on wooden bodies

[Doug Dawson]

Just looking for separate thoughts on regular tempered glass being used to flatten the soles of both metal and wooden planes

I wrote the book on plane sole flatness, so to speak, and the point was that you don't usually have to do that, on a functional plane from a reputable manufacturer.

[Robert Hazelwood]

Was your piece of granite custom ordered or was 5”x18” a standard size
Also was it purchased online or locally

I bought it at woodcraft several years ago.

[michael langman]

I found using glass and sand paper on a cast iron tablesaw top to flatten iron planes very difficult to accomplish. The front of the plane wants to remove the metal as you push the plane in a forward motion. Not good.
I got a straight edge, and a good flat mill file and removed the metal at the high spots as Warren has noted. Had the plane, a#6 flat in an hour or so.

[Matthew Springer]

I'm in the same boat as Robert, I got a 6" x 18" surface plate off of Amazon for not that much. I got the various sandpaper rolls from Klingspor. It's the same one woodcraft stocks and even came wrapped in woodcraft packing tape. IIRC grizzly has the same one in stock too. I've found for doing a lot of flattening, sandpaper on granite surface plate works well for me. I have not tried loose grit slurry over surface plate. I have an old 603, a 6 and a 4 that all need a bit of flattening but I'm waiting for the workshop to thaw out.

Note that for wood planes, all the old books talk about truing one plane off of another, so this clearly works good enough to produce working flat woodies.

[Phil Mueller]

Michael, try sanding forward for a number of strokes, and then turn the plane around and sand for the same number of strokes. I do this with anything that I sand on a solid surface to help minimize the natural uneven pressure pushing something back and forth.

[michael langman]

Thanks for the advice Phil. I'll remember that next time I flatten a plane.

[Rob Luter]

Tempered glass can have roller wave distortion. Annealed glass (float glass) will be flatter. That said, it's probably insignificant as it's measured in the low thousands of an inch. It takes a pretty expensive gauge to even measure it.

I use 1/4" float glass mounted on MDF blocks as a base for abrasive films. It is very flat. When I need a larger flat surface to lap a plane sole I use my table saw top or a granite plate. Counter and kitchen shops are a great resource for granite sink cutouts and other scraps of suitable size.