Jack Plane Flattness. How flat should it be?

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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
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<<<<<<<<<<<<<<< SNIP >>>>>>>>>>>>>>>>>>>>>>>>>>>
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 (<.005). There are those that will say <.001, but I'm just not that good with a plane yet.
If it's new, take it back because of the twist. That is not acceptable. Flattening the sole for the hollow is not a major job if you don't mind pushing it on sheets of 60, 120, 150, 240, 400 grit glued to a hunk of MDF. Probably an hour's work.
Regards.
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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.
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Heel, Toe, and Mouth should be flat and co-planer. And flat enough that you are satisfied with the output - no flatter.
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DJ:
I suspect (tho' can't prove) that the deflection of an 18" long hunk of 1/2 (or 3/4) MDF under any reasonable hand pressure is so minimal that it's not in the equation. Is MDF flat - well it sure seems to be. My 1/1000 DI doesn't wiggle when I pass it across a clean piece (actually passing the piece under the DI). You're not going to put a heck of a lot of weight on it when sanding, at least not if you want the paper to survive.
As I said in my original response, the twisting that causes the rocking is far more of a problem than the absolute flatness of the sole. And, as other posters have noted, good enough is good enough.
You can read Jeff's notes at
http://www.amgron.clara.net/planingpoints/planefettling/fettling.htm
He's kinda considered an authority on "fetting" a plane.
Anyone know the origin of "fetting"? I've assumed it was a translation from the Scots brogue, but maybe there's another reason for the term.
Regards.
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It is 'fettling'. Here's a good explanation:
<http://www.worldwidewords.org/qa/qa-fet1.htm
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Tom Banes wrote:

Oxford Concise:
"N. English make or repair. -- Origin ME (in the general sense 'to prepare'): from dial. fettle 'strip of material', from OE fetel, of Germanic origin.
I assumed it was divergent from 'fiddle' but that's a different word altogether, with its own origins.
er
--
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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.
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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?
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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.
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Charles Self wrote:

Listen, I got the 12x18 and wish I'd gotten the 18x24, and I'm sure I'd have still made wishes had I gotten that. :)
When I got them from enco (they have both grade B and A plates and the A plates are only a few dollars more) and enough other stuff to bring my total to $200 the shipping was free. BFG! Hey, is that a gloat?
er
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Get a piece of glass. It's flat within the size of the finest grit you'll be using to lap the sole. If you're using paper, which has no thickness standard for either the backing or the thickness of the abrasive, MDF on your TS will be fine.
Essence of lapping, after all is getting to an _average_ by keeping things moving.
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You can get surface plates certified to very very tight tolerances.
djs wrote:

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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.
http://www.amgron.clara.net/index.htm
You 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.
http://pages.sbcglobal.net/mike_in_katy/PlaneWood/Default.htm
...hope this helps,
--
Alex - "newbie_neander" woodworker
cravdraa_at-yahoo_dot-com
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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
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snipped-for-privacy@comcast.net wrote:

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
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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.
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Bruce Barnett wrote:

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
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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.
http://japanwoodworker.com/page.asp?content_id &59
You 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
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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
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