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Planer Tool Holder Sizing

M.B. Naegle

Feb 7, 2011
Conroe, TX USA
I was doing some QC tool holder sizing for a couple of our lathes and while updating some information on our machines post dimensions, was looking at the old list of Lantern style holders by Armstrong and Williams showing which holder systems go well which which swings of lathe, and got to wondering if there is a similar sizing reference for planers and shapers? Looking at the old Armstrong/Williams catalogs, they size the tool holders made specifically for shapers/planers (gang holders and indexable holders) by the size of the bit, but there's nothing to tell you which holder works best with which machine (that I see). Is it purely job specific?

For my Whitcomb Planer (30"x30"x10' belt drive), I've been rounding up holders that are roughly a #5 holder (in lathe terms), which can hold a 5/8" bit, but the clapper has lots more room. In terms of broad nose single point cutters, I'd think you could do a pretty wide swath with a 5/8" bit, even when it's ground with a radius. With hand ground lathe bits I typically go for the smallest bit I need for whatever form I'm grinding, but often find that 1/4" or smaller go to the 9" lathe, 3/8" to the 10", and 1/2-5/8" for the 14" or bigger. Is there any similar sizing protocols to consider for shaping and planing? On my plainer there isn't a way to change speed/feed**** other than how you initially set up the overhead pulleys, but do material and horsepower play into it like they do on other machine tools?

****On edit: There's no speed variation, but you can change the step-over, IE feed rate via adjusting the ratchet mechanism.
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Since nobody seems to know, I'd guess you've asked this question about 90 years too late.... Unfortunately.

On the oldest lathes I've seen there's always just a mixed pile, and although a size specification may have existed, just like now, companies likely just opted for the cheapest tooling they could get away with for the job at hand. And I'm sure just like these days, the machinists grumbled about management making boneheaded cheapo purchases on undersized tooling and expected the same high output of larger more expensive tools.

Aaaah, the good ole days.......
The clapper clamps on my planer are big enough that trying to hold onto a smaller tool feels like throwing a hotdog down a hallway, but I've thought about making some U-shaped channel adapters that I could more easily hold onto smaller holders if it was needed. OTOH, I also have some lantern holders that someone in the past milled and ground down to fit in smaller lanterns and into QC tool post holders. While it would be more economical to replace them, I've thought about welding them up and milling them back to their nominal sizes again.
I've done some.. interesting setups to get smaller tooling in my shaper lantern tool post. Fortunately it's pretty much limited only to one's imagination as far as tooling setups go. If it hold and cuts, it must be a good setup.

Although pictures of some of those setups are necessary or they clearly didn't happen!

When it comes to modifying or restoring tooling back to original, once you start you will have entered the Twilight Zone. A haunting circle of unrelenting monotony wrapped up in a recurring circle of neverending welding and machining. Job after job, day after day.
My old Cincinnati planer I had years ago came with a tool holder with a built in clapper block. Tool shank was about 1-1/2 square from what I remember from then. Tool bit size was 1/2" square. I also had a set of old Clark tool holders that would hold 5/8" sq tool bits. They had 1 x 2" shank on them. The planer was a 22" x 22" x 72" stroke.
The big Rockford dad had at work used tool holders with 1 x 2 shanks with 5/8" sq tool bits. Of course it was much newer than the one you have. Seem like I recall reading in one of the machinery hand books from the 1930's - 1940's about mentioning tool sizes for various size machine tools of the time. Want to say, it was from the American Machinists handbook I think it was called.