All you might want to know about sole "flatness"

[Timberwolf]

Excellent video.  The degree to which that plane's sole was out of flat is a good indication of how poor the manufacturing process was when it was made.  My father had a No. 4 made in the 80's and you couldn't get a decent shaving out of it to save your life because the sole was so far out of flat. 

He covers a lot of important things about getting a plane sole flat like making sure the frog is installed.  One might ask why not just use sandpaper on a flat surface?  It's very easy to put uneven pressure if lapping  on sandpaper to the point where you do more damage than help.  The technique of continually checking progress helps to mitigate over lapping (or scraping in his case).

Interestingly enough, I use a carbide scraper to sharpen my pruning tools.  It's much more convenient for curved surfaces.

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Gray cast iron "can" warp. We used to manufacture machines for making concrete blocks.. Two major parts for the machines were heavy castings..We staged them for machining based on their age, and used the oldest ones first. We stored the castings in the back of the lot outside and laying on the soil....The plan was to allow the newly cast parts to "rest" or acclimatize for about a year before being machined..Auto engine cylinder heads used to be very prone to warping and we machined a lot of them in our jobshop...Their exposure to radical temperature swings were probably the most common cause of it.

https://www.finewoodworking.com/forum/wa...t%2C%20etc.

[Tony Z]

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Gray cast iron "can" warp. We used to manufacture machines for making concrete blocks.. Two major parts for the machines were heavy castings..We staged them for machining based on their age, and used the oldest ones first. We stored the castings in the back of the lot outside and laying on the soil....The plan was to allow the newly cast parts to "rest" or acclimatize for about a year before being machined..Auto engine cylinder heads used to be very prone to warping and we machined a lot of them in our jobshop...Their exposure to radical temperature swings were probably the most common cause of it.

https://www.finewoodworking.com/forum/wa...t%2C%20etc.

Jack,

Did you also do the casting or were the blanks purchased? There was a foundry (no longer in business) about a 1/2 mile from a building I own in a nearby town and their fresh castings were stored outdoors. There is a foundry in a town about 20 miles from me, still in business and their fresh castings are also stored outside. When I was in college, one of my summer jobs was working for a guy that was scrapping out industrial buildings and I would haul scrap to the first foundry. There, I was instructed that a casting needs seasoning and the best way is at least a year outside in the elements, with longer time even better.

As you said, temperature changes can cause warpage, as can castings finished before proper seasoning. I have no idea how LN or LV do their modern castings, but there has to be some sort of normalization done.

[Tony Z]

Excellent video.  The degree to which that plane's sole was out of flat is a good indication of how poor the manufacturing process was when it was made.  My father had a No. 4 made in the 80's and you couldn't get a decent shaving out of it to save your life because the sole was so far out of flat. 

He covers a lot of important things about getting a plane sole flat like making sure the frog is installed.  One might ask why not just use sandpaper on a flat surface?  It's very easy to put uneven pressure if lapping  on sandpaper to the point where you do more damage than help.  The technique of continually checking progress helps to mitigate over lapping (or scraping in his case).

Interestingly enough, I use a carbide scraper to sharpen my pruning tools.  It's much more convenient for curved surfaces.

A guy like Tablesaw Tom, that knows how to fixture a plane, will do a far better job than any Saturday morning "ham and egger" taking a plane to sandpaper. The same goes for a tradesman that know how to scrape or even one that knows how to fixture and use a flycutter on a mill.

You can't beat a man at his trade!

[Timberwolf]

Jack,

Did you also do the casting or were the blanks purchased?  There was a foundry (no longer in business) about a 1/2 mile from a building I own in a nearby town and their fresh castings were stored outdoors.  There is a foundry in a town about 20 miles from me, still in business and their fresh castings are also stored outside.  When I was in college, one of my summer jobs was working for a guy that was scrapping out industrial buildings and I would haul scrap to the first foundry.  There, I was instructed that a casting needs seasoning and the best way is at least a year outside in the elements, with longer time even better.

As you said, temperature changes can cause warpage, as can castings finished before proper seasoning.  I have no idea how LN or LV do their modern castings, but there has to be some sort of normalization done.

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Tony, we didn't do the castings...only the machining..I'm pretty sure LV and LN use Malleable iron for their tools...as did Stanley on some of their tools..I have spokeshaves and #80 scrapers that are marked with an "M" denoting malleable iron. As you know, the treatment makes tools less brittle and less prone to breakage, and of course, more expensive to make. The castings used to have to be kept at a red heat for quite a period of time to allow internal structural change. I'm not sure but I think keeping them red hot for a period of time eliminates the need for "seasoning" of the cast iron. Allan may be able to answer that question.

[Timberwolf]

Excellent video.  The degree to which that plane's sole was out of flat is a good indication of how poor the manufacturing process was when it was made.  My father had a No. 4 made in the 80's and you couldn't get a decent shaving out of it to save your life because the sole was so far out of flat. 

He covers a lot of important things about getting a plane sole flat like making sure the frog is installed.  One might ask why not just use sandpaper on a flat surface?  It's very easy to put uneven pressure if lapping  on sandpaper to the point where you do more damage than help.  The technique of continually checking progress helps to mitigate over lapping (or scraping in his case).

Interestingly enough, I use a carbide scraper to sharpen my pruning tools.  It's much more convenient for curved surfaces.

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One thing just occurred to me about glass....it bends...laying it on a surface that IS NOT flat can cause the glass to bend, making for a surface that is not truly flat. So we are laying the plane on an uneven surface and on sandpaper which is not intended to be perfect, using uneven pressure, expecting the results to be perfect. Not saying the plane won't be somewhat better, but it won't be in the same league as Tom's machine ground planes and the ones from LN or LV..

[AHill]

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One thing just occurred to me about glass....it bends...laying it on a surface that IS NOT flat can cause the glass to bend, making for a surface that is not truly flat. So we are laying the plane on an uneven surface and on sandpaper which is not intended to be perfect, using uneven pressure, expecting the results to be perfect. Not saying the plane won't be somewhat better, but it won't be in the same league as Tom's machine ground planes and the ones from LN or LV..

Jack, when I lap anything on sandpaper, I use a flat granite plate as the substrate.  I've seen others use a table saw or jointer top as well.  I'm not a fan of using glass as my "flat" surface.  I'd rather use something more stable.

[AHill]

Jack,

Did you also do the casting or were the blanks purchased?  There was a foundry (no longer in business) about a 1/2 mile from a building I own in a nearby town and their fresh castings were stored outdoors.  There is a foundry in a town about 20 miles from me, still in business and their fresh castings are also stored outside.  When I was in college, one of my summer jobs was working for a guy that was scrapping out industrial buildings and I would haul scrap to the first foundry.  There, I was instructed that a casting needs seasoning and the best way is at least a year outside in the elements, with longer time even better.

As you said, temperature changes can cause warpage, as can castings finished before proper seasoning.  I have no idea how LN or LV do their modern castings, but there has to be some sort of normalization done.

Tony, it's not necessary to season all cast iron, but the process for those that require it can be accelerated by the temperature cycles seen in outside storage.  I would not leave castings exposed to rain, ice, or snow, and I'd adequately protect them from corrosion.  Fresh cast iron is prone to warp because it's easy to build up internal stresses in the casting process.  Not so much with ductile iron like Lie Nielsen and other modern plane makers use.  Trying to release the internal stresses by heat treating risks premature cracking, because the stiffness of cast iron is such that heat treating causes dimensional changes too quickly that the iron can't tolerate.

[Tony Z]

Tony, it's not necessary to season all cast iron, but the process for those that require it can be accelerated by the temperature cycles seen in outside storage.  I would not leave castings exposed to rain, ice, or snow, and I'd adequately protect them from corrosion.  Fresh cast iron is prone to warp because it's easy to build up internal stresses in the casting process.  Not so much with ductile iron like Lie Nielsen and other modern plane makers use.  Trying to release the internal stresses by heat treating risks premature cracking, because the stiffness of cast iron is such that heat treating causes dimensional changes too quickly that the iron can't tolerate.

Thanks Alan,

My "exposure" to the seasoning was more than 50 years ago! Whether the raw castings were covered or not, slips my mind.

TZ

[Timberwolf]

Thanks Alan,

My "exposure" to the seasoning was more than 50 years ago!  Whether the raw castings were covered or not, slips my mind.

TZ

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I remember how our castings were just stored outside in the dirt exposed to mother nature

[EricU]

I remember seeing castings at Delta just sitting outside.  They get cleaned up later, no reason to fight the rust.
Melancholy thought.