Going through an old box and haven't a clue

I measured (with my "hi-tech" jig) So pardon the glaring problems here- everything is measured to the 1/8 inch- here is a shot of my measuring jig:
Measure jig.jpg Just 2 framing squares- line up the same measure on each leg and "poof"... Now THATS science...ish

Went through ALL the gears in the box and found/grouped the ones that meshed together first- Then did tooth counts and major diameter measures.

There is more here than initially thought. there are several different "groups" of gearing- I divided them by which ones meshed together (But I have no ideas on pressure angles or PD as of yet- so bear with me...

Here are the "original" gears (Double keyed) laid out- measurements to follow
IMG_20200531_103634324.jpg (GOING RIGHT TO LEFT)
ToothMajor DIA (inches)Thicknessmaterial/markings
362 3/45/16Zamak
362 3/41/2Aluminum home-made
442 7/85/16Zamak
4631/2Boston Gear marked GB46
4635/16Zamak
483 1/85/16Zamak
523 3/81/2Bost Gear GB52
543 1/25/16Zamak
563 5/85/16Zamak
603 7/81/2Bost Gear GB60B (gear has offset stamp area)
644 1/85/16Zamak

More to come-
 
Awesome!

The first one you pictured (looks like a 45-tooth compound), has an approximate diameter just under 3". A 45 tooth, 16 pitch gear has a diameter of 2.9375", so that matches a 16 pitch gear. The 46-tooth, 3" gears are 16 pitch. The 44-tooth gear (2.875") is a 16 pitch gear. It looks like most are 16 pitch gears. The 44, 46, 48, 52, 54, 56, 60, and 64 tooth gears are at least.

The exceptions are the two 36-tooth gears. A 14 pitch gear that has 36 teeth is 2.714" (just under 2.75"). I'd suggest seeing how well they mesh with the 16 pitch, just to check, but they are likely out of place.

Here's the formula if you'd like :

Diametral Pitch =​
(Number of Teeth + 2)
Diameter of gear in inches​
 
The Boston gears are aftermarkets, but the look of those is explicitly a Craftsman 101-style lathe. Not sure about those two 36 tooth gears, unless the diameter is 2 3/8 - that 2 3/8 would be closer to a 16 pitch. They do look like they mesh okay with the others, but my brain doesn't work well if the math doesn't check out.
 
OK so on to Grouping number TWO... Double keyed but these do NOT mesh with the first/original group

These are gear+pinion configuration- One having a spacer between the main gear and the other no spacer-

Group 2 pic two.jpg Group 2 pic one.jpg

BOTH PINIONS are 20T and same size (1 3/8 Dia and 1/2 in thick)

34T2 1/2 Dia1/2 in Thicklabeled GB34 NO SPACER
45T2 15/16 Dia1/2 in ThickLabeled GB45 w 5/8 in spacer

The Double Key Bushing is 3/4 inch OD and 1/2 inch ID

According to Amazon this is a 16DP 14.5 deg PA
 
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The Boston gears are aftermarkets, but the look of those is explicitly a Craftsman 101-style lathe. Not sure about those two 36 tooth gears, unless the diameter is 2 3/8 - that 2 3/8 would be closer to a 16 pitch. They do look like they mesh okay with the others, but my brain doesn't work well if the math doesn't check out.

Thank you for the formula- I had downloaded/printed a sheet for DP and PA calculations this afternoon- Looks like I will be getting friendly with the math soon!

So my mind just says use calipers and measure the root and the major diameters and split the difference for the proper diameter for calculations- How exacting do I need to be... 0.01 inch?
 
Now on to Randy's possibility-
My needed 127 would be nearly 11" in diameter.

Sorry to report the 127T is only 7 1/8 in Diameter!

BUT- this brings me to another question- it has pin holes at an angle through the hub- locating or locking pins as the 100T is secured w one (See Pic)

Dual Gear Rear Detail.jpg This is the rear of the 127T plate

Dual Gear Hub Hole a.jpg Here is a hub shot of the 100T gear with empty pin hole in hub

Dual Gear 100 127.jpg And the pic of the happy couple...

127T7 1/8 dia3/8 thicksteel
100T5 5/83/8 steel
64T NOT PICTURED3 5/83/8steel

No stamps, marks or otherwise identifying markings- painted in grey epoxy though...
 
The Double Keyway gears look like Atlas/Craftsman gears.
Many of those were used with the Double Keyway and paired up together.
 
The 7 1/8" diameter , 127-tooth indicate it is an 18-pitch gear, and could be suitable for a South Bend 9/10k lathe. The same applies for the 100 tooth. There are definitely going to be other applications, but the only real intended application for a 127 tooth gear is full conversion for metric thread pitches. For example, you could use that gear as an index to machine something else with 127 holes (or similar).

The previous batch, the 34 tooth is a 14 pitch, and the 45 tooth is a 16 pitch. It looks like a very eclectic assortment of gears. 14 pitch for the small ones, 16 pitch for most, and an 18 pitch metric conversion.
 
Just a comment; if the 100/127 pair will mesh with what you have, I would say to hang onto them. They'll come in handy some day soon.

They look to be 16 DP though, and I would like to get in line for them. Just say the word and they're taken. I have a 100/127 pair but in aluminium(homemade). I'd like iron much better.

.
 
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