Fellow woodworkers,

Recently, I bought a semi-professional #7 jointer plane, which doesn't mean much by my country standards, since we get Chinese rip-offs that are sold under famous brand names (and prices). Nevertheless, it was the best I could get and afford.

Naturally, this jointer needs a lot of work before it can be used. One of the sides is at a perfect 90° to the sole, however, the other one is at about 87° to the sole (meaning that the sides are not parallel). If I'll ever have to use it on shooting board, I'll use the good side.

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However, the big problem is that the sole is nowhere near flat. The shape is concave along the length, and somewhat across too. I have a calibrated granite block, so I placed some 60 grit sandpaper on it, crossed the sole with marker, and then started "planing". After 5 hours (not exaggerating) of sanding, I gave up, because I'm nowhere even close to flattening it - there's just way too much material to remove.

Here are the photos of the progress of flattening, taken about once every hour.

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As you can see, at first, the progress was good, but as I went on, the contact surface increased, meaning there's more and more steel to grind. By the end, I realized this is going to take forever, likely longer than that.

Even though the marker pattern indicates that the ends and the sides of the sole have been flattened, placing the jointer against flat granite revealed that the ends are still way too high. I have no idea why the sandpaper didn't fix the ends - maybe it isn't pressed against granite well enough, springs up, and follows the concave shape of the sole?

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Anyway, I'm looking for an alternative way to flatten that sole, because doing it traditionally is neither accurate, nor fast enough. My arms are killing me already from all that grinding. I would appreciate any suggestions you guys might have...

  • First off, bravo for what you've achieved so far! I don't want to add an Answer as @scanny has pretty much covered it as I would have, but I did want to address a couple of issues. Before anything else I think you might find it useful to see this previous Q&A. IF you decide to continue you can do it using abrasives (by localised sanding) but I highly, highly recommend you switch to filing or scraping, and to help decide on that I think what you should do now is check how the plane works as it stands. – Graphus Apr 23 '18 at 12:55
  • What brand is this by the way? – Graphus Apr 23 '18 at 12:57
  • Silverline, why? – J R Apr 23 '18 at 15:13
  • Re. the brand I wanted to know if it was one I was familiar with. Silverline don't have a great reputation as you know, but as with all cheaper tools there are better and worse examples. They're a little more expensive but I'm a fan of Faithfull as I have two and a friend has one and all three were great, needing at most basic fettling to be usable. – Graphus Apr 24 '18 at 14:50
  • Faithful are not imported in my country, unfortunately... We have just Silverline, Stanley and Irwin, but unfortunately, Stanleys and Irwins are just Chinese rip-offs sold under these brand names and prices, but they are little better than the Silverline. I checked... – J R Apr 24 '18 at 16:56

Filing and scraping are the traditional ways to flatten a cast iron surface by hand. These processes will be significantly faster than "sanding" on a surface plate.

Done well, a scraped surface can easily be within .001" flatness and even .0001". I also find scraping really satisfying, although I'm glad I don't need to do it to pay the bills (it takes time).

The rough idea is that you spread marking medium, like Dykem Hi-Spot Blue in a thin layer on the surface plate, rub the surface on that, and then scrape off all the areas that marked blue (the "high" spots). You do this over and over until it all marks blue.

There are a few excellent videos on this:
Restoration/Tuning of a block or hand plane to highest accuracy w. files, scrapers, edge & plate

Scraping basics - Scraping flat - Part 1

Hand Scraping - How I do it.

There are several others if you search on "metal scraping".

The process can be started on a budget, making marking medium from oil and pigment, or certain types of artist oil paint (clean off carefully each time if you choose this route :)

A scraper that kind of works can be fashioned from a file, but something with at least high-speed steel on the cutting edge is much more effective. The edge is sharpened at a 95 degree included angle (negative rake), which may seem a bit odd at first.

A file may be used for roughing. Alignment is a problem with filing and it's very, very easy to round over the part (sole in this case). So be careful if you choose this option.

By the way, assessing bottom flatness by tipping the sole onto an edge, as you do in the last picture, is only valid if that far side is perfectly flat. The bluing/transfer-marking approach will give you more reliable indication, or you can slip feeler gauges underneath while it's sitting on the surface plate.

  • Thank you for your answer. Very useful. I guess I will go this way. I searched and was unable to buy marking blue for steel anywhere in my country. You said I can make it myself from oil and pigment? Could you please tell more about it? What kind of oil, what pigment should I be looking for? – J R Apr 23 '18 at 22:02
  • The recipe is detailed at about 4:15 in the third video. Wes uses masonry pigment/coloring, powder mixed with concrete to give it color. The oil probably doesn't matter too much, I expect motor oil would work fine. Probably not vegetable oil though. – scanny Apr 23 '18 at 23:51
  • Oh, thanks, I was just halfway into the second video. Will check it out. Thank you again for your answer, this info is extremely useful. – J R Apr 24 '18 at 6:24
  • one more question, if I may. In several of the videos you posted, people say that oil based marking medium is a poor choice. Are there any other alternatives that I can get on a budget, since specifically formulated mediums for this application are not sold in my country? – J R Apr 24 '18 at 8:32
  • Can you give me mm:ss markers for where they say that? The most effective marking compounds are oil based, they just are hard to get off your hands. I have heard that this "fitting" compound is not great: amazon.com/Permatex-80038-Prussian-Fitting-Compound/dp/…, maybe that's what they mean. Or are they talking about oil-based artist paints? – scanny Apr 24 '18 at 8:38

Having a friend who previously owned a machine shop gave me a slightly different perspective on this question. I checked The Google and found that my thought isn't all that far "out there."

Someone in the above link has posted that he had a machine shop use a surface grinder on his plane to get to within 0.01" of flat, as well as squaring the sides.

There's some discussion about performing the grinding with or without the frog plate and blade in place, but that seems to be personal opinion with a bit of anecdotal evidence.

If you have a small job shop in your area, you may find a shop owner willing to take on your task for a reasonable fee. My friend would have been shooting for better than 0.01" as he typically managed 0.0005" for his CNC stuff.

  • I already asked around. Very few shops in my country have surface grinding machines, and most of them are 20-30 years old, so you can't expect any accuracy. Even if I could, the typical price for such service would exceed the value of the jointer several times over. – J R Apr 22 '18 at 20:05
  • A 20-30 year old surface grinder might give you better results than a newer model, considering that they were manufactured for long life. I would expect my friend's shop grinder to be that old. The pricing aspect would vary, but his rate would mean possibly a thirty dollar (US) or lower price on the job. – fred_dot_u Apr 22 '18 at 20:18
  • Well, when I called and asked around, explaining the situation, the cheapest quote I got was 110 euros ($135). I don't earn that much in half a month... – J R Apr 22 '18 at 20:24
  • Wow, that's rather expensive. It would pay for a lot of elbow grease, that's for sure. – fred_dot_u Apr 22 '18 at 21:07
  • It appears you have contact at the front, back and throat, that is enough to make the plane perform well. Perfect? no but certainly useable – Chuck S Apr 23 '18 at 2:11

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