What is this?

[Carl Miller]

It looks like a small core box plane. The metal is 6-3/4 long and each side is 2-3/8" wide. The only marking on it is W L THATCHER which I pressume is the manufactuer. It may also be a shooting board plane since the blade is only sharp on the long side (it would only be good for boards up to 1/2" thick). The body is brass with nickle plating and has a hang hole drilled in it (not done at the factory). I saw it and it was only $5 so I bought it (whattayagonnado). Any help is appreciated.

[george wilson]

That is a core box plane.

[lowell holmes]

What do you do with a core box plane?

[Jason King]

core boxes of course :)

[Bill Houghton]

What do you do with a core box plane?

See http://www.supertool.com/StanleyBG/stan8.htm#num56 and http://www.woodmagazine.com/woodworking-tools/hand/the-stanley-57-core-box-plane/

[Bob Glenn]

Used mostly be pattern makers, I think.

[Jeff Burks]

A core box plane is used to cut the recess shapes in a core box. This is almost exclusive to patternmaking for foundry work so the planes are not very common. The core box is used to mold the disposable cores that are placed in a sand mold to prevent the molten metal from filling the area that will house a cylinder or hole of some specification. The core is broken out of the cast part after the metal has cooled. The core box is a reusable mold, usually split into 2 halves. The core material is usually some kind of silica that is hardened in the core box. Obviously the core has to stand up to the heat of the molten metal, and also be easily removed from the finished part. It is much easier to understand if you watch a few videos on foundry sand casting.

This video (http://www.youtube.com/watch?v=hCBRfrPV8BY&feature=related) shows a set of small engines with the patterns (with core prints) and cores used to make them. He also shows the core box that was used to mold the cores that prevent the metal from filling the cylinder during casting. The core box shown is a modern aluminum split box. In the old days they were made from wood and formed with various tools including the core box plane. He also shows the binder that is mixed with the core sand to harden the core in his oven.

This video (http://www.youtube.com/watch?v=wG9JzeZYPi4&feature=related) shows the the core being set in the core print recess in the sand mold.

This video (http://www.youtube.com/watch?v=UVqvgPn4jIE&feature=related) shows the making of a complex core for an intake manifold casting.

This video (http://www.youtube.com/watch?v=h-c4_Ukqgx4) might help explain some things about metal shrinkage and why you don't want to cast parts with thick solid areas. Thus it should be evident why you would want to use a core in the first place. The whole video series is well done and worth watching.

The core box planes were replaced in the early 20th century by shop machinery that could make the same cuts. You may have noticed that there are router bits called core box bits (http://ecx.images-amazon.com/images/I/51HJGCE7JYL.jpg) that perform the same function as well.

The shape of the core box plane should be self explanatory. The right angle design prevents the plane from cutting beyond the depth of a half cylinder as shown in this diagram (http://images.meredith.com/wood/images/p_corebox5.gif).

There are only a handful of US patents for Core Box Planes:
13,957 (http://www.google.com/patents?id=5G9RAAAAEBAJ&zoom=4&dq=patent%3A13957&as_drrb_ap=q&as_minm_ap=0&as_miny_ap&as_maxm_ap=0&as_maxy_ap&as_drrb_is=q&as_minm_is=0&as_miny_is&as_maxm_is=0&as_maxy_is&pg=PA1#v=onepage&q&f=false)
307,223 (http://www.google.com/patents?id=qbJFAAAAEBAJ&zoom=4&dq=patent%3A307223&pg=PA1#v=onepage&q&f=false)
345,278 (http://www.google.com/patents?id=DVZTAAAAEBAJ&zoom=4&dq=patent%3A345278&pg=PA1#v=onepage&q&f=false)
554,466 (http://www.google.com/patents?id=KUhNAAAAEBAJ&zoom=4&dq=patent%3A554466&pg=PA1#v=onepage&q&f=false)
556,114 (http://www.google.com/patents?id=p7xQAAAAEBAJ&zoom=4&dq=patent%3A556114&pg=PA1#v=onepage&q&f=false) - The Stanley #57 Plane (http://img.photobucket.com/albums/v80/harnett65/Album%206/pic1027.jpg) & with all 3 sets of wings (http://www.patented-antiques.com/images/cyntools/XX-c-tools-on/c-planes-d/Stanley/SSU-plns/57/PIC00014.JPG) for making very large core boxes.
695,668 (http://www.google.com/patents?id=xCNJAAAAEBAJ&zoom=4&dq=patent%3A695668&pg=PA1#v=onepage&q&f=false)
751,671 (http://www.google.com/patents?id=XjgtAAAAEBAJ&zoom=4&dq=patent%3A751671&pg=PA1#v=onepage&q&f=false)
916,344 (http://www.google.com/patents?id=iEBXAAAAEBAJ&zoom=4&dq=patent%3A916%2C344&pg=PA1#v=onepage&q&f=false) - The Stanley #56 Plane (http://www.patented-antiques.com/images/cyntools/XX-c-tools-on/c-planes-d/Stanley/56/P4160122.JPG)
1,269,569 (http://www.google.com/patents?id=MLtGAAAAEBAJ&zoom=4&dq=patent%3A1%2C269%2C569&pg=PA1#v=onepage&q&f=false)

As for the original post: I have no information and could find nothing on WL Thatcher. It certainly looks like a core box plane, and may be a European variety of some sort. But then again it may be modeled after a core box plane and intended for some obscure use in another industry.

[Jeff Burks]

Some additional information about the above listed 751,671 Bayley plane (http://books.google.com/books?id=L5Fwt1ouu5QC&lpg=PA80&ots=J1wtUqMBtq&dq=Bayley%20Core%20Box%20Plane&pg=PA80#v=onepage&q&f=false%3Cbr%20/%3E).

Lee Valley has a short article about the plane in their newsletter (http://www.leevalley.com/newsletters/Woodworking/2/1/collection.htm).

Bill Monroe (http://www.stinsonvoyager.com/HomeFoundry.htm) has a nice website for his hobby foundry with many pictures of pattern making (including core boxes and silica sand cores). There is a link (http://www.stinsonvoyager.com/BayleyCoreBoxPlane.htm) at the top of the page for a gallery of the Bayley plane cutting a core box.

[Carl Miller]

I agree with you Jeff. It must be a core box plane - I'd never looked at a #56 before these postings. This one looks like a #56 in the cutting area. Lots of good posts from you guys. I should not have looked at the casting videos - I've got a feeling I may have to side track my wood working hobby and try making some castings.