Jack Plane Flattness. How flat should it be?

[djs]

I am looking for some advise on how close to flat a 14 inch jack plane should be. I picked up a plane yesterday and today I was checking it out. The first thing I checked was the flatness of the sole relative to the top of my table saw. There was a slight rock from corner to corner. I measured this to be about 0.008 of an inch using a feeler gage. The other thing I noticed is that the middle of the plane had about a 0.007 inch gap using the feeler gage technique.

Is this plane sole good enough to be used as a scrub plane? It would seem like it to me, but I am just guessing.

Is it flat enough to be used in less aggressive jack plane applications? If not, then how flat and how straight should a 14 inch jack plane's sole be?

I don't have experience using planes or tuning them, but I am willing to try it.

My options are: 1) Use the plane as is. 2) Return it and try to get one that has a flatter sole. 3) Try to flatten the sole.

So what do the experienced woodworkers think? I would appreciate what ever advice you may have.

Thanks In Advance,

DJS

[Tom Banes]

IMHO as a scrub lane it'll do OK to hog out wood. As a jointer or smoother, I'd want no twist and a flatter sole (

[kkfitzge]

Could be that the the plane is flat, and your TS isn't. Check against a known standard before you do anything. Grizzly sells 9x12" granite surface plates for about $30.

[AAvK]

I would manualy flatten it on 100 grit, then 220 grit, then 600 aluminum oxide wet dry paper made by Norton, the papers glued (3M super 77 spray) to a thick piece of float glass. The glass, you might find cheaply at a local junk shop like I did, new it is expensive, but mine is an awesome 3/4" thick. You could also use an old piece of marble counter top.

Mark the sole with a full length and width squiggle with a permanent marker and have at it, this is so you can see the details of the hills and valleys, and the progression of your work.

It takes hours and elbow grease to get it done. But, I have done it with a few Stanley hand planes, and if you're on a budget or prefer to be, it is well worth it.

Their are several websites that explain how to tune a handplane as well. But once done, it will work beautifully. "Tuning a --" being the key word idea for 'net searching.

can also have the plane refurbed by Mike_In_Katy (Texas). He does new baked- on japanning, and new totes and knobs in different woods... did an awesome bit of work on my #8, and new cherry. He does offer a warentee on the japanning.

this helps,

[extiger]

Using a straight edge, and holding 6 of my planes up against sunlight, the gaps were bad.

I sanded and sanded, going as low as 60 wt sandpaper. Then 120 wet dry. After two weeks of this, the soles still had hollow patches near the mouth and heel & toe dips. The guys on oldtools.org informed me that only my No. 3,4,4 1/2 and 5 plane need to be dead flat. I was getting nowhere, and had expended $25 on sandpaper.

So I asked my neighbor, a machinist by trade, if his workplace had a good surface grinder. He said they make MRI equipment for hospitals. I gave him about 50lbs of planes and he returned two days later with transformed tools.

The soles were within .0005" flat, with no hollows anywhere. And, the soles are at 90 square with the sides. I gave him $50 for his trouble and consider myself lucky. These are all Pre-WWII planes. Some are pre WW-1 planes.

I've heard of guys using a belt sander clamped in a vise to accomplish the same thing. By hand, you might be digging the proverbial tunnel to China.

Gary Curtis Los Angeles

[extiger]

Using a straight edge, and holding 6 of my planes up against sunlight, the gaps were bad.

I sanded and sanded, going as low as 60 wt sandpaper. Then 120 wet dry. After two weeks of this, the soles still had hollow patches near the mouth and heel & toe dips. The guys on oldtools.org informed me that only my No. 3,4,4 1/2 and 5 plane need to be dead flat. I was getting nowhere, and had expended $25 on sandpaper.

So I asked my neighbor, a machinist by trade, if his workplace had a good surface grinder. He said they make MRI equipment for hospitals. I gave him about 50lbs of planes and he returned two days later with transformed tools.

The soles were within .0005" flat, with no hollows anywhere. And, the soles are at 90 square with the sides. I gave him $50 for his trouble and consider myself lucky. These are all Pre-WWII planes. Some are pre WW-1 planes.

I've heard of guys using a belt sander clamped in a vise to accomplish the same thing. By hand, you might be digging the proverbial tunnel to China.

Gary Curtis Los Angeles

[David]

None of my LV plane's soles are perfectly FLAT. The aren't supposed to be. In order not to rock, they are deliberately machined ever so slightly "hollow", by design. I've spoken with them to confirm what I'd already suspected; if you run a new LV plane over 600+ paper, it will polish only the edges. The interior of the plane's sole is maybe a .001 recessed from the edges. My shoulder planes are dead flat, but the 22" jointer plane, LA smoother, and scraper plane all have identically machined soles and they work well. I just checked the LA block plane--same thing. I trust LV to design their planes well, so I have no issue with the planes never being truly, literally FLAT. They cringe on the phone if someone says they have lapped the soles of their LV planes.

Dave

[AAvK]

They don't need to be "entirely dead flat" at all. To be good enough for accurate flat planing, just enough flat areas where it doesn't rock at all. If the plane is to be used for chuting (or with a shooting board), the sides of the body need to be an exact 90 perpendicular to the sole... that's the hard one... as you had done.

You got the great deal! ... hhhmmmm ... I know a couple of machinists!

The method I used worked, it took too long, but no rocking.

[Bruce Barnett]

BTW - This style is described in my book that describes how to tune a Japanese wooden-soled planes.

They sell a special plane (like a scraper plane) just for this purpose.

[David]

Bruce, I don't own, nor have I ever used, a wooden plane. What advantages and disadvantages do they possess? Except for one tiny cheapy, all have are the LV planes ductile cast iron planes. (I think that's the correct description)

The scraper is a bit convex?

Dave

[Bruce Barnett]

I'm not an expert, but I have one (1) wooden/Japanese plane I bought about 20 years ago, and the Toshio Odate book on planes.

The slight concavity of the sole I described is to reduce friction.

No. You scrape fron one side to the other side - across the grain.

If you look at the side of the plane, it touches the surface at the front edge, near the throat, and at the end.

I think the LV planes have sides that touch the surface. This is different from the Japanese style of reducing friction, where the sides do not touch the surface.

A long Japanese joiner can have several "points" of contact, so the bottom is like a "wave" if you understand what I mean.

As to advantages - Wooden planes can be cheaper, and you can modify it easier, and you can make your own wooden plane easier than making an all-metal plane.

IMHO the biggest difference is that you pull the Japanese plane towards you, instead of pushing. The blades tend to be made from two kinds of metal, and are thicker. These bi-metal blades allow a harder edge, while retaining flexibility. You can now get bi-metal blades for metal planes, and thicker blades.

A second difference, given my limited experience of one, is that the budget Japanese plane REQUIRED tuning. One can use a cheap metal plane without tuning (if one is woefully ignorant), but until I tuned my Japanese plane, I couldn't even get the blade to approach the throat.

Here's a short article on tuning a Japanese plane. The Odate book gives more detail.

have to remove the blade when you are not using it. Moisture changes etc. Metal planes are indifferent to humidity.

I can't compare a western style wooden plane to a Japanese style, and I don't know if I have covered everything. Perhaps Mr. Knight and others will elaborate and correct my mis-understandings?

I think the biggest and more important thing is how well the plane is tuned. A well-tuned metal plane will out-perform a poorly tuned wooden plane, and vice versa.

HTH

[CW]

[djs]

CW, No I don't know how flat my table saw is, but I did move the plane around in a quite a few positions on the table saw top and also on the extension table top and every place I put it the result was about the same. So I am pretty sure the plane isn't flat by approximately the amount stated.

I considered testing it on a flat piece of glass, but how flat is that? Especially if it is sitting on a non-flat table. Flat is a hard thing to be absolutely sure about.

DJS

[djs]

It sounds like flattening it down to less than 0.005 should be pretty easy as you suggesty, but is that good enough? Flattening it down to

0.001 would require a better flat reference than my table saw top.

I would question how flat a piece of MDF is. It seems like it would depend on how flat the tabel top the MDF is resting on. A little pressure down on the MDF or any other flat plate of glass or marble, while pushing down on the sand paper, would also force the MDF to conform to the supporting table, which is probably not all that flat.

On the other hand this plan has two high spots, one at the toe and one at the heal, and both are limited to about 1 to 1.5 inch from the end. It seems like all I would have to do is work on one end of the plane on the sand paper at a time.

[djs]

This sounds like a good idea. However, I would like to get a flat reference surface a little larger than this. The 9x12 could handle my

14 inch number 5 Jack plane, but I will needs something a little larger for the longer planes. Do you know if these granite surface plates are actually certified flat to a certain tolerance?

[djs]

How do you know how flat your piece of glass is? How do you support it so that it maintains its flatness when you are working a plane on top of it? I would think that any pressure down on the glass while working the plane's sole would deform the glass plate to a non-flat surface.

[djs]

Wow, 6 planes flattened to 5 tenths, for only 50 bucks. I don't have that option. And I may not need it either. I was talking to my brother-in-law a little while ago, and he is a big hand plane guy, and he advised me that smoothing planes don't really need to be as flat as a jointing plane. This is just the opposite what you say the folks at oldtools.org tell you. Now I wonder who I should listen to. I'll have to visit oldtools.org to see what they are all about. Thanks for the reference.

[djs]

Well, this make some sense, a flat surface around the entire edge of the sole, and hollowed out in the middle by about 0.001. Are you sure that the slightly hollow is 0.001 inch. How did you measure that? I am wondering how I might put such a feature on my plane.

[djs]

I didn't mention it above but my plane is metal. I have a couple old wooden planes, but they don't get me to excited. They need more tuning than the one I picked up yesterday.

DJS

[Charles Self]

Check the Grizzly catalog. According to the copy, these are flat to plus or minus .0001". Certified? I don't know. I've got the 9x12 and wish I'd gotten the 12x18 or 18x24, but the shipping charges are ROUGH! No ledge 18x24 costs $44.95, with $58 shipping. Add an 18x24 stand, at $49.95, and you add $38 to shipping.