Scrub iron radius / use questions

Re: Scrub iron radius / use questions

Jack Guzman from Maine

>Moses,my ECE leaves a 1/2" furrow also.I haven't changed the angle from the factory setting.I think this makes it easier to take deeper cuts.To even out the ridges I just follow with a 5.It works very well this way,especially if I have to remove alot of material to even out a twisted board.I think a wider swath would increase the power needed to push the plane.I'm really new to this though so I could be wrong in my thinking.---Jack

Re: Scrub iron radius / use questions

Michael Stadulis, in Gloucester County, NJ

>Hi Moses,

Trust me, you really do want that narrow furrow. Get rid of the longer radius arc on that iron. Scrubbing goes much faster when you can take a pretty deep cut, but narrow cut, and then criss-cross from 90 degrees. This gives you good control of depth til you want to get out a jack.

Mike....who face joints all his boards with a 40 before I surface plane

Re: Scrub iron radius / use questions

Jim Crammond in Monroe, Mi

>Moses,

I agree with Jack, my scrub plane takes a shaving (actually a chip) about 1/2' wide and 1/16" to 1/8" thick. I'm not sure what the radius of the edge is. I think that the narrow, deeper cut allows you to remove wood more quickly with less effort. It usually takes 2-3 passes at 45 dgrees in both directions to get rid of all signs of the rough cut wood.

The scrub leaves a very rough surface that I next use a jack plane on. This blade also is radiused quite a bit. I asked Bill Clark of Clark and Williams what radius he uses on his jack planes and he told me that he wasn't sure of the measurement. He said he places the blade blank on a five gallon bucket and scribes a line using the outside of the bucket as a guide, then grinds to that line. I ground an iron of a wooden jack to that radius and it seems to work great for this step. Two or three passes with this plane, then I use a another jack with an iron with very little radius.

Jim Crammond

It depends

jim reed @ Tallahassee

>The radius should vary according to the degree of hardness of your stock. Set a broad radius for soft woods so that you can get a wide chunk. Set a tight radius for harder woods and reduce the width for hard, tough woods. It should be matched to your arm/leg strength and endurance. Scrubbing is a place where less is more, ie, it is easier to make a few light passes. Good luck.

All I can say is...

Dan Donaldson

>If you can put a radius on a plane iron to that level of accuracey I want to see the setup that does it ;-)

Re: Scrub iron radius / use questions

Jerry Nicholson

>I assume that you don't spend much time trying to assure that the sole of a scrub plane is flat. I just got a #40 and the blade has some major nicks so I am going to have to ground off quite a bit of metal. I also assume that sharpness of the blade is much more important than the actual radius and smoothness of the curve. Please tell me if I am wrong there.

Jerry

Here you are Dan, the perfect scrub blade. *LINK*

Derek Cohen (in Perth, Australia)

>I posted this jig a short while ago (see Link below). It is used here on my belt sander, but I have also used it on a vertical grinder.

Regards from Perth

Derek


Grinding a perfect scrub blade

Re: Here you are Dan, the perfect scrub blade.

Dan Donaldson

>I remember that one and it is great. What I was referring to is the statement of a 9.0156 in radius. I think that even your jig wold have a problem giving me repeatable radii at that level of precision ;-))

Re: accuracy

Moses Yoder in White Pigeon, MI

>I figured I might get some comments on that. Actually, that figure is only accurate to the four decimal points, so it is not an exact radius. I just put the arc in on autocad using 1/32" offsets and copied the radius calculation off of the properties. In reality, I would set up to grind a 9" radius and wouldn't really care to what point it was accurate so long as it worked.

In spite of the comments that a narrower cut is better, I am going to have to try for a wider cut so it doesn't take as long to plane the board. I'll report back on how this works. What I have found fron the little bit of scrub planing I have done is that there is very little resistance to the plane when planign at a 45° angle to the grain. The shavings break apart ahead of the iron very easily, so it is very different from planing with the grain.

accuracy for scrubbing??? *LINK*

HC Sakman

>Hi Moses,

I'd suggest the same thing. Wider radius (10~to~12 inches) and lighter/shallower cut. It does make sense to start with narrower radiused blade though, and wider radiused plane should come right after the most of the roughness of the board is taken away first. Only thing I can forsee that following jack may be harder to push due to shallower valleys and flatter ridges left by the wider radiused scrub plane blade. I guess that's yet to be experienced to be confirmed.

Good luck.

Chico...


My site

Easy scrubbing???

jim reed @ Tallahassee

>My experience is that it totally depends on the wood. I scrubbed some rough walnut and it cut like soft butter. Then I scrubbed some HARD maple and almost ripped my spine off its hinges!!! It took many 15 minute sessions over a two week period to scrub and flatten a little board that was 8" x 36". I ended the sessions when I was covered with sweat and had it dripping down onto my glasses. ps--the shop AC was on. Some boards will bring you to your knees.

Re: Easy scrubbing???

Pam Niedermayer - Austin, TX

>That's what headbands are for, Jim. Also helps avoid big blobs of sweat on the board.

Pam

3" for 40-1/2

Todd Stock

>3" radius is what I use, which is close to what my scrub came with, as well as the #3 that I used in the old days before the 40-1/2. A full width cut in some woods would be a good workout - the 3" radius gives about a 3/4" or so cut to a sixteenth or so, and the narrower chip makes the plane easier to guide. I think the wide blade on some scrubs must have been there for taking white pine or other soft woods down a bit faster.

I thought

Jim Reed @ Tallahassee

>the sweat added a nice natural stain to the board.

Re: I thought

Dan Donaldson

>No, it is blood that makes the natural stain;-)

Re: Stanley's idea

paul womack

> some careful measuring

BugBear

Way too flat

Roger Nixon

>Scrubs work better cutting narrow and deep. I don't measure radius, I just put about 1/8" camber in the blade (#40 1 1/4" blade) which would roughly be 1.5" radius. This sound similar to what Jim Crammond mentioned above. I do not try for full width "shavings", I just go with the depth the hardness of the wood allows.

"radius??"

John Truxell-Svenson (jvs)

>When I got my 40 1/2, I though that the curve was too tight. Depth-adjusted for consistent effort, on hard stuff, it was digging a narrow channel, and on soft stuff, going too deep. I just jigged it and put a ~1/2" flat on the front, and have reshaped it freehand since then when it is time to go back to coarse stones. At this point, it is a fairly even thumbnail, tighter in the corners than in the middle, and can be set for even effort at a range of depths with a fairly consistent chip width--exactly what I was looking for. I'm basically not sure why a mathematical radius is even a goal.




/jvs

Radius is a compromise

Jim Reed @ Tallahassee

>I agree. The radius is probably just a compromise. Best situation is probably to have several irons ground specifically for certain types of wood. Should not take too much time to load up the proper blade--scrub blades are easy to set and lock in place.