Thread: Plane Adjusting Mechanism

Stanley used this type of mechanism on their short-lived Gage series of planes. Sargent had a similar series called Auto-Set. Early Shelton planes also used a similar design.

Looks very cool, but I've never seen or used one personally. The Bailey design obviously won the war.

V

Yes - Sargent Auto Set planes used it.
The frog is fixed but adjustments of the chip-breaker/cap iron control the fineness of cut.
The lever cap doubles as the chip breaker and is adjustable for depth.
It is an ingenious and robust system and works very well
Tom

You've piqued my interest, Picko, but as it says on the web pages, the images are low-resolution. I think I have figured out how the two separate adjustments actually work by applying a little imagination. In view of the relatively recent revival of interest in the function of cap-irons, having a plane that has adjustable for setback seems like a good thing, thogh not sure how it would work in the real world. (Tom, have you used one of these sargants & do they have genuine advantages over the typical fixed blade/cap iron system? I'm particularly interested in how well the 'direct' screw adjuster works.)

My take is that direct screw adjusters require very fine threads to work well on a 45* blade angle. As a crude example, I've tended to use either M6 or M5 screws for "direct" adjusters on low angle planes like this:
Ebony infill chariot plane.jpg

Both M6 & M5 have a 1mm pitch which gives approximately 40 thou linear movement per revolution (apologies, I have to think in 'thous' when talking about blade adjustment, it's one conversion I've never managed to master in metric!). With a 15 degree bed, a full turn of the thumbwheel will move the blade 40 thou, but the actual change of depth is only ~10 thou (40 x sin 15). So a 10th of a turn gives you a 1 thou change in cut depth, which is just manageable for arthritic fingers. However, a full turn of a 1mm pitch adjuster on a 45* bed gives the same linear blade movement (40 thou) but a change of 28 thou in depth. A 10th of a turn now changes the depth by nearly 3 thou - fine adjustments become a bit more challenging!

The solution, of course, is to use a very fine thread, but that brings its own problems with rapid wear & backlash, as Mr. Norris discovered a hundred years back.

In my opinion, the reason the Bailey adjuster swept all before it is because it works so damned well. It uses a relatively coarse thread on the thumbwheel screw, but that's taken care of by the highly offset pivot point of the yoke. I haven't ever worked out how much blade movement you get from a full turn of the thumbwheel, but it's equivlent to using a very fine thread with a 'direct' system like the Norris & imitators. The crude cam-in-a-loose-slot coupling to the blade assembly does add backlash, but fine adjustment is still very easy. It has all the hallmarks of success, simple, reliable & durable....

I've tried adding screw adjusters to 45* planes I've made, with limited success. One works well enough & the counter-screw system I used makes for very fine adjustment, but it's not as easy as adjusting a Bailey on the fly because the screwed lever cap has to be backed off to move the blade. This can cause unwanted lateral movement & on a bad day it can take me several frustrating attempts to set this plane to both a fine & even cut. The cream on the Bailey mechanism is that cammed lever-cap which can be adjusted to apply just the right pressure to hold the blade in position, but still allow the adjuster to move it easily.

The only negative thing about the Bailey adjuster imo is that it's not very practical for the home-builder to copy (& obviously unsuitable for an infill).

Cheers,
Ian

I haven't seen that type, but there have been others like it (early on, a french type - maybe 100 years before - where the cap could be adjusted while in the plane).

What caused them to not ever be widespread? Probably two things
1) they're not functionally better in a way that's meaningful
2) part of 1 - once you use the cap iron for a while, the time to set it close is an extra 5-10 seconds in a bailey plane and it's a very reliable robust plane

Something that added a dollar or two of price back then would've doubled the price of the planes to people who were price conscious.

There isn't an adjuster that I'm aware of at this point that's more practical than a stanley type, though there are plenty that look more artful and cost more to make.

This is public domain stuff.

US Patent: 1,151,301 - Sargent Auto-Set Benchplane

Thanks raffo, much clearer images in the link on that page. You just saved me a couple of bucks .
No I don't intend trying to make one, just interested.