Practical lapping advice needed

[Ken Cohen]

Hi-

I'm trying to fix up two older planes and need help on the amount of lapping required. For background, I had good luck bringing an old Stanley #4 back to life, but help from an instructor.

This time I'm on my own with a Union #5 and a Stanley (Baily) #6. The #5 was a local consignment shop find, the #6 purchased at Liberty Tools in Maine on vacation.

My biggest issue is with the #5 (see photo below). I have a good hour into it with 80 grit -- and am making little progress against a big low spot in the back and a somewhat smaller low spot in the front. Also, dip behind the blade is also evident. I've given it a rough run, and it seems to take a noticeably thicker shaving at the end of a board. My goal is a good user, not perfection. Thoughts? (Maybe it's simply a few more hours of elbow grease. Maybe I got a clunker -- luckily it cost next to nothing)

By contrast, the #6 looks pretty good (right pix, sorry about upside down) after several light passes over the 80 grit. (Probably consistent with its much higher price). I think it needs a bit more work to level out the opening -- and then call it quits. Again, thoughts?

As always, advice and counsel much appreciated.

Ken.

[Andrew Gibson]

What Kind of 80 grit paper are you using.
I found that a belt sander belt, cut open, cuts a lot faster and lasts a lot longer then regular paper.
I found this out with a worn out belt I had laying around.

That #5 looks like it is just going to take some time.
This is also why I like Corrugated soles, that and my inherited #7 is Corrugated and I looked for planes to match when I was starting out. Sad thing is I only have a #3 and #5 at the moment to match my #7. I still want to find a #4.5 and a #5.25. just need $ and to need other tools less.

[Richard Niemiec]

Frankly, a jack plane is generally used for rougher work, and the sole does not have to be perfectly flat. so long as the toe, the area immediately in front of and behind the mouth, and somewhere in the back are coplanar, declare victory and start using the plane.

I'd sooner spend my time perfecting my iron sharpening rather than lapping a #5. Smoothers, on the other hand, could benefit from the work.

[Kemil Pepin]

+1 on what Richard said. What is your set-up for lapping? How often are you refreshing your sandpaper? In an hour of lapping, I would have changed paper several times. It is really only sharp for a few hundred passes, then it really starts to cut a lot slower. Also, use a vac, a brush or magnet to clean the paper frequently.

[David Weaver]

Planes are fine. The 6 looks like it'd be done for my taste, even if you wanted to use it as a long smoother.

I'd work the five until you've got fresh metal around the mouth and then stop. It'll probably have fresh metal at both ends and the mouth at that point, too.

Best and fastest setup to lap is a long glass shelf with psa roll aluminum oxide paper. You would be able to do each of those in ten minutes.

Don't know what folks have to pay for the shelf, but mine from a local glass shop (8x42 inches and 3/8ths thick - thicker would be better) was $20.

Add a sandflex block to go after that 80 grit and you don't need to go higher on grits, either, especially if the paper has a little wear and isn't cutting as deep.

Lapping is about doing as little as you need to, because doing more than that likely is creating a problem rather than solving it.

[Ken Cohen]

Thanks for the responses.

FYI, I'm using a zirconium aluminum sanding belt spray glued to a long left over granite block from a kitchen remodel. I brush it after each 10-15 strokes. Still, probably time to replace.

I share the general view -- lap as little as possible to get the plane performing. Seems like the #6 is fine. No work required.

I'll keep at the #5 until I have fresh metal fore and aft of the mouth (I'm almost there). My guess is that the rest of the plane will remain much as shown in the pix. Please let me know if anyone would recommend a different approach.

Finally, any thoughts on the thicker shaving at the end of the board with the #5? Plane?Technique?

Thanks.

Ken

[Jim Koepke]

The paper will wear fast and depending on how you lap, it can wear more in the center.

How flat the sole for a #5 really depends on how you are going to use it. For a scrub plane, forget it. It could look like a banana and still do the job. Same for rough work.

If you are going to use it like a smoother of for a lot of shooting board work, then you might want it a little flatter.

Perfection is nice, but it is often not worth the cost in sore muscles and backs.

For my lapping set up, I bought a 4' piece of scrap granite from a monument shop for about $25. It works great for not only lapping planes, but it helps to speed up back flattening on old chisels and blades. It is also good for putting on a new bevel.

Here is a shot of it:

Picture 3.jpg

jim

[Jim Koepke]

Finally, any thoughts on the thicker shaving at the end of the board with the #5? Plane?Technique?

Have you tried pushing the plane over the work without down ward pressure? I had a plane once that flexed a bit. It was cured some what by lapping the sole.

It could also be caused by the shape of the surface on the board. Have you tried other boards?

jim

[Trevor Walsh]

Out of curiosity how flat should a #7 be? If I get blue-out on the toe, mouth and end should I be set? If I'm going to me edge jointing should I go for flatter?

[Steve Branam]

The way I set up my #5 is with a cambered iron, 8" radius (down to 7" or 6" for heavier shavings). This makes it take fairly aggressive shavings, especially when the iron is advanced to project by as much as 1/16"-1/8", so the flatness of the sole is almost irrelevant. Then take shavings more diagonally and across, even criss-cross, less lengthwise. This is midway between a scrub plane and a jointer.

Thick shavings at the end is probably just from keeping force on the front of the plane as you go off the end, cresting the board. I have to remind myself not to do that, ease up the hand pressure on the front just before that hand reaches the end. Diagonal shavings should help (just don't crest it on the far side of the diagonal).

[Prashun Patel]

I find it useful to work iteratively. Move to turning your blade now, install it, and shave away. If the results are to your liking, you've saved a lot of time. If not, then you'll have learned a lot about how much each variable matters - or not.

Do you own a Worksharp or a belt sander? They can be used to do a lot of the initial flattening of soles and blade backs.

[David Weaver]

Out of curiosity how flat should a #7 be? If I get blue-out on the toe, mouth and end should I be set? If I'm going to me edge jointing should I go for flatter?

Assuming you mean if you put dykem or marking fluid on the plane, and it gets rubbed off at the front of the mouth and at the two ends, then you are in good shape.

A picture always helps.

For practical purposes, I would stop there if my assumption is correct.

[Trevor Walsh]

Assuming you mean if you put dykem or marking fluid on the plane, and it gets rubbed off at the front of the mouth and at the two ends, then you are in good shape.

A picture always helps.

For practical purposes, I would stop there if my assumption is correct.

Yes, sorry, blue-out is an old machinist's term for the process you describe. I'm going to give Prashun's idea try and see how I do, before I start grinding anything.

[Robert Culver]

I just finished lapping and cleaning up a stanley #40 scrub plan I used *80 grit norton 3x belt sanding paper. I had an old paint brush handy and brushed off the paper every 30 passes or so. But you will need to change the paper a few times as said in the previous post as it will wear fast. The 3x did last a few hundred passes. The you can almost feel it slow cutting. when it does take of the old and glue a new to the lapping plate.