Decoding Hollows and Rounds

Re: Decoding Hollows and Rounds *LINK*

Ted Shuck, Centennial, CO

>Bill,

All your questions about hollows and rounds should be answered by this very informative article by Ken Greenberg. The upshot is that there is more than one standard.

Regards,

Ted


Sizing Hollows and Rounds

thanks, that was handy

bill tindall

>

Re: Decoding Hollows and Rounds

Feix B.

>Thanks Ted,

I just came here to post the same question as Bill did :)

- Felix

Purchasing a set

Jim Reed @ Tallahassee

>Some people think you need to purchase H&Rs in matched pairs. I do not agree with that myth. Here is what I think:

1) Purchase a new C&W set or purchase a matched set from a single mfg.

2) If you plan to use them on hardwood, make sure they are York pitch.

3) Half set is OK (even sizes from 2 to 18)

4) The most handy are 2-8

Good luck with your woodworking.

Why?

Adam Cherubini

>Some people think you need to purchase H&Rs in matched pairs. I do not agree with that myth.

Me neither.

Purchase a new C&W set or purchase a matched set from a single mfg.

So you don't think matched pairs are helpful, but you think a matching set is? Why?

Adam

Why set?

Jim Reed @ Tallahassee

>I think what really matters is having graduated rounds and graduated hollows. Moulding operations generally require variations in size that require a different sized plane of the same shape (round or hollow). In addition, York pitch can make a big difference. In my exerience, I have found 45 degree stray H&Rs to be pretty worthless.

The wonderful thing about standards...

Rob in Peoria

>is that there are so many to choose from...

Rob's prepping for vacation on Friday, and tapering all week...

The most common system is the British system

Larry Williams

>I explained it a few weeks ago on the main forum. I think it also gives the most useful range of sizes. I'll repost it here;

Here's an article that I wrote some time ago for our web site. I just haven't had time to get it put into tables and uploaded. One thing to remember is that, contrary to what you might see or read elsewhere, it's important the planes cut the full width of the soles.

The Sizing and Numbering of

Hollow and Round Planes

By Larry Williams

Clark & Williams

http://www.planemaker.com

In his book, Woodworking Planes, Al Sellens says; "The size numbering refers to iron width but the numbering schemes appear to have been established to confound the scholar and to confuse the collector." It’s not difficult to understand his confusion. There often seems to be no standard to the sizing of hollows and rounds.

W.L.Goodman, in British Planemakers from 1700 makes a pretty good case for there being two different British numbering systems. He offers little about the sizing of early hollows and rounds, and there appear to be few surviving sets from which to gather the information.

Hollows and rounds from before about 1750 were generally unmarked as to their size or number. Examples given by Goodman are some of the earliest recorded commercial plane makers--the succession of makers starting with Granford (1687-1713), then Wooding (1706-1739) and on to Jenion (1738-1778). Like most things about old planes, I’m not sure this should be a considered a rigid rule. We have a JENION plane with early features that is marked. It is possible the number was added at a later date but it seems to be original.

One standard appears to develop in British planes by the beginning of the 19th Century. Variations from this numbering and sizing information are common. The major British makers seem to have followed this emerging standard relatively closely. Under this system, numbers correspond to the number of 16ths of an inch in cutting width; except on those planes wider than ¾” the increment of change switches to 1/8”. For example, a number 11 would be 11/16” wide; number 12 would be ¾” wide, and a number 13 would be 7/8” wide rather than the expected 13/16ths. This change, I believe, was an attempt to offer planes which allowed for visual weight of the profiles cut. Visually, there’s little difference between a 1 ½” diameter cylinder and a 1 5/8” diameter circle.

The width of hollows and rounds directly relates to the radius of the arc they cut. Most planes cut 1/6th of a circle, or 60º of arc. This means the cutting width of these planes is equal to the radius of the arc -- a number 8 plane will have a ½” cutting width and cut an arc with a radius of ½”. It is convenient to judge the size of a circle by the width of the sole of the plane. My observation is that this too has some exceptions. Larger hollows and rounds tend to cut less than 60º and often cut a radius larger than the sole of the plane would indicate. For instance, a #18 from an unused set of GRIFFITHS, Norwich (c. 1860) planes we have cuts a cylinder with a 2” radius rather than the expected 1 ½”. This matches the #18 profile of a little used set of MOSELEY (c. 1810).

Another exception is that number 1 planes were listed as being 1/8” bare or less than 1/8” but probably larger than 1/16”

Many American plane making firms closely followed the British system. Some didn’t and used a variety of systems. Greenfield avoided the increment change found in the British system. Sargent offered only planes that represented the even numbers of the British system but numbered them sequentially. Those American makers who didn’t follow the British system appear to have had their own different systems and no alternative American system is apparent.

When selecting a numbering system to follow, we chose to follow this later British system except to stay with planes cutting 60º of arc. This way the plane’s width will be the radius of the arc cut. Woodworkers today and in the past found the smaller profiles the most useful. Often old sets don’t include the larger sizes, and today’s woodworkers generally seek the smaller sizes for their own use.

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I'd have to put the chart into some image format to post it here and would rather not take the time. It'd slow down responding too much.

The number 1 hollows and rounds we offer do have a 1/16" sole because we don't see the need for what is essentially two pair of number 2 planes.

Below are examples of 1/2 set of even numbered hollows and rounds.

Re: The most common system is the British system

Bill Houghton, Sebastopol, CA

>So you offer planes that will cut a 1/16" radius circle? Wow.

Re: The most common system is the British system

Larry Williams

>don't put a micrometer on 'em, they're not to those tolerances but they're very close.

I keep forgetting an image gets dropped if you preview a post. Here's the photo I intended to add:

Thanks for the info

Jim Reed @ Tallahassee

>Thanks for the info and the picture.

Are those the bodies for the bullnose version?

Bill Houghton, Sebastopol, CA

>