Hand Tools

Subject:
Re: Questions on sole flattening

TomD
>"It seems common to buy a Stanley plane that someone may have been using successfully and flatten its sole as a step in refurbishing it. The question relates to if, or when, this step provides value in performance.

Never. I did a lot of that when I started out in the 70s, and it was a huge time hole. Back then I got new planes from LV by either stanley or record, and they were terrible. I mention LV because we know they were selling the best they could find. I had major sources of unflatness ahead of the mouth on one plane, so the whole sole required flattening before one could get to the mouth. Even worse was a record block plane with an adjustable mouth where the whole sole was flat but the mouth plate was hanging in air and had zero effective surface below it. We had to deal with this crap back in the day, but today it is completely unnecessary with the quality of new tools we have. Or one can make a whole wooden plane in 45 minutes, so I see no utility to the sow's ear approach.

>1. So, how flat is essential for peak, or acceptable, performance?

Flat is flat, but with planes you need it to be flat relative to the cut and intended use. So in the 70s period I related above, my dad bought me a Record jointer, and I still use it today. It was perfect out of the box. So the projection of the blade, relative to the accuracy of the sole, relative to the kind of work to be done are all important. A jack does not need as good a sole as a jointer, or a polishing plane.

I used to have a list of different plane functions. These can dictate the plane accuracy, or one can use a good plane in a less demanding function. I am not sure, but it goes a bit like this:

1) Knocking off chips. Sorta like a hatchet. You have a handle with a blade, and a lot of mouth. But it can be refined as with a router plane.

2) Transverse cuts. So you get something like a molding plane where the main function is to transfer the shape of the blade projection to the surface

3) Transverse and longitudinal, which is most things we think of as planes, but there are huge differences in required accuracy.

There are about 6 type, but you get the point. Sole accuracy depends a lot on what you want.

>2. Related, if a novice planer is using an unacceptably unflat plane what would they experience that would tell them they need to flatten it?

3. If an experineced planer is using an unacceptably unflat plane what would they experience that would tell them they need to flatten it?

I think it is basically the same for both. I think on the second or third plane I made I got shavings of 4/10000th of an inch. I don't think plane setup is all that big a deal, or why anyone would settle for less than they need. It is a lot like sharpening. There is not an amateur or professional standard for razor sharp. At least not at the low end threshold, which is basically all one needs + a grit.

The most obvious tip off is that you have blade projection, but you can't get a shaving. But generally you can see the problems, or measure them.

4. How do you flatten a plane on sandpaper glued to something flat without overcutting the leading or trailing edges?

I think the usual suggestions are to load a blade under regular tension, but not projecting, and concentrate your weight over the mouth, not on the handles.

A simpler method is to hollow grind the sole. You don't need flat, you need contact points in plane with a fully flattened pad ahead of the mouth. You can belt sand, or hand scrape.

If you use a surface plate and scrape, then you are not weighting the sole. And you don't have to use a scraper, which is not a shaping tool, you can attack the sole with anything that will take metal away from areas it is not needed.

Of course, if you are not thinking mechanically, but rather as to the surface you need to sell or present a polished plane to your friends, you have an objective beyond the functional.

A belt sander with a good platen will work. Also a milling machine, or surface grinder.

I have had two surface grinders, really KO LEE sharpeners, but they can do surface grinding, and they cost me around 150 each. Take that Shapton stones. I think that milling machines are all one really needs, but sometime you may not want that heavy a cut. On a milling machine a block plane would only take maybe 5 minutes to surface, once it is indicated in. I haven't done a really large plane yet on the milling machine.

Some of the most accurately set up planes are Japanese planes, they are set up to take cuts in the tens, on the polishing planes, and they are wooden planes. They are also very fast to set up. I have the specialty planes for relieving the sole, but in practice I have used everything from routers to belt sanders, and often set the final phase in with PSA sandpaper on granite. So it is simple to have perfect, sometimes all that metal gets in the way.

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