Author Topic: Top Jaws  (Read 997 times)

Offline Alston

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Top Jaws
« on: January 27, 2023, 10:44:51 AM »
Do any of you know when two part chuck jaws were in invented/patented for the scroll chuck? Iíve seen the patent online for the first scroll chuck from 1840 so it seems highly likely that two part chuck and top jaws were also invented that century? Any links appreciated if you have them.  ;)

Offline Overbuilt and Overkill

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Re: Top Jaws
« Reply #1 on: February 15, 2023, 05:15:15 AM »
No links with any definitive historical information, so this is just some logic being used. The first "chucks" would have been separate bolt on screw adjustable jaws for use on what was at the time the usual standard and slotted face plates. Likely and not much later, today's independent 4 jaw would have been invented with additional improvements for higher precision jaw guidance etc. would have evolved into much like we have today. The invention date of precision surface grinding could likely be linked to that as well. 3 jaw scroll chucks would have been a logical later development, your 1840 date for example. Highly refined heat treatable steel alloys were expensive and about impossible to find before the Bessemer process was invented in 1856. So that date coincides somewhat with your dates for the invention of the scroll chuck. Invented and in common general use are two different things obviously. At best and prior to that date, then cast iron would have been used. Not impossible that iron was purposely hardened just by rapid cooling. Overall I'd think but don't know for sure given the high carbon cutting tools prior to the invention of HSS around 1900, those chuck jaws were probably unhardened anyway and meant to be trued after wear became a factor.

Again and only my best guess, but hardened jaws to resist wear and added soft top jaws would have been developed once that steel refining process made proper and dependable heat treatable steel alloys a lot cheaper. Roughly that would have been after 1862. Not illogical to assume two piece and soft top jaws might have been introduced prior to 1900. But nailing down an exact date might be as difficult as finding out if the Morse Tool Company really invented the Morse Taper, when they did, and why or if they did, then why they chose those varying and irrational uneven taper angles that aren't consistent between sizes. The precise information about the invention date and use of those two piece jaws is I would think very likely unknown today. And patent dates don't always coincide with what was already in known general use. Someone frustrated enough and who didn't have an available tool post grinder was probably the inventor of that soft jaw idea. :-)

Offline vtsteam

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Re: Top Jaws
« Reply #2 on: February 15, 2023, 01:39:19 PM »
For a lathe, I think bell chucks were the first true chuck. But I can't prove that.

To me a chuck is different than a vise, in that a vise has a stationary component and a chuck has all moving grippers. That's pretty arbitrary, and not necessarily how others think of it, or in line with current naming conventions. But having made various faceplate "two jaw chucks" from scratch (eg an attached angle iron with a bolted on plate, and the Vee version or so-called keats type) I think they were really technically faceplate vises, when I compare them to the bell chucks that I've made.

There are also true 2 jaw chucks made now, with 2 moveable jaws, and I also think bit brace has a true 2-jaw chuck. But I think the bell chuck probably goes way back. It is just one step more complicated than a single set screw in a fixed size arbor journal.
Steve

Offline vtsteam

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Re: Top Jaws
« Reply #3 on: February 15, 2023, 02:27:35 PM »
A homemade faceplate "2-jaw chuck" after Gingery:

Steve

Offline steamer

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Re: Top Jaws
« Reply #4 on: February 15, 2023, 02:43:55 PM »
I have a chuck at home.with a late 1800s patent date with renewable top jaws....I'll see if I can grab some pictures
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