Hand Plane Surface Grinding
#21
Curious after grinding all three sides of a plane, I measured the surfaces on a coordinate measuring machine (CMM).

The sole was flat to within 0.0012 inches. On one side, the angle to the sole was 90.023 degrees. On the other side, the angle to the sole was 89.988 degrees. I figured it was close enough for most purposes.

The downside is that results like this require 3-4 hours of shop time, most of which is consumed by fixturing and indicating.

[Image: 33449400164_d790a01da3_c.jpg]
Bob Page
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In da U.P. of Michigan
www.loonlaketoolworks.com
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#22
Having done a few green cast iron Stanleys. The trick is a good 6x48 belt sander. Once done there, lapping is short work.
A man of foolish pursuits
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#23
I had one machinist out of 4 or 5 that knew enough how to take the time to properly fixture a plane for grinding. The ones he cleaned up for me (minimal material removed) performed like a new LN, with a proper blade. The ones done by the other guys, not so much. Time needed for the one that knew his onions was roughly two hours for a #4 or 5 size plane. At shop time ghosts, this equates to about $100.
Waiting to grow up beyond being just a member
www.metaltech-pm.com
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#24
Can't seem to edit my post, but the machinists were my employees.
Waiting to grow up beyond being just a member
www.metaltech-pm.com
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#25
The casting thickness is fairly thin on a Stanley plane. That being the case the lever cap can in fact deflect the sole slightly when tightened. As mentioned in this post a proper fixture for those planes with iron and lever cap in place is time consuming to achieve. In other words impractical for just one plane.

Under the best circumstances it takes at least an hour to grind the sole of a plane and in some cases longer. Most of my plane soles are 5/16" thick so as you might imagine that's not an easy thing to deflect.

With a well dressed stone and proper amount of material removal the metal should not heat up to be more than just slightly warm to the touch, however at just warm the center of the sole just behind the mouth will rise slightly. Before the final passes the sole of the plane should be allowed to cool to completely to room temp cool. When I resume grinding I notice that the stone will only be hitting the toe and heel of the plane because the center of the sole has retracted to it's cool state. Very light passes, usually 2 to 3 tenths per pass will then get the sole truly flat with no hollow behind the mouth. 

As you see this is a finicky and time consuming process, thus the expense involved. 

This is all assuming that the grinder being used is still in spec and is producing a flat surface when all is said and done.

When a surface grinder needs maintenance it is a costly matter. Bearing replacement in the spindle can exceed the cost of a good used machine. Therefore a machine that is being used to service the needs of another industry is most likely going to be preserved for that need.

Ron

[Image: hhwp2.jpg]
"which plane should I use for this task?......the sharp one"

http://www.breseplane.blogspot.com/
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#26
I can't agree with Ron more. Farting around with any precision tool, even to do personal printing on a 50 - 60 thou printer in my industry, was grounds for a permanent vacation. Besides, Ron is the one justified in producing a tool so precise it is silly overkill for the work that it is intended. His item cost is absorbed in the total.  I kick furniture to rest on the imprecise floor because I don't have matchbook covers anymore.

Sometimes, the motivation for perfection fades after a while.
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#27
Most old cast iron planes are straight enough to work properly as they are though I have come across two that weren't.

The best way to make them flat is most likely by filing and scraping as that doesn't induce any clamping stresses. Scraping is a rather common technique among peope who rebuild old machinery.

Here is a picture from when I scraped an old straightedge flat.


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Part timer living on the western coast of Finland. Not a native speaker of English
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#28
TGW said, "Most old cast iron planes are straight enough to work properly as they are though I have come across two that weren't."

My experience as well. I had an early round-sided 604 that wouldn't take a shaving. I checked the sole and it was badly concaved - looked like a rainbow. I have no idea how it got so warped; never seen that before. I sent it to tablesawtom and he worked his magic on it. That was a couple of years ago. It's as flat today as it was the he returned it to me. It works as well as any plane I have.

[Image: image_zpsfe9767a5.jpg]
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#29
Sounds like the answer is no, nobody knows a guy.
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#30
Unless the sole is a banana, slight hollows in a sole don't matter if the toe, heel and areas before and after the mouth are co planar. This can be accomplished lapping with sandpaper on a flat surface. Less is sometimes more.
Credo Elvem ipsum etiam vivere
Non impediti ratione cogitationis
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