Seneca Falls Lathe Parts

[Pease]

I’m looking for 3 Seneca metal lathe gears:

1. Gear has number 31 printed on it; 2 1/8 inch OD; 1 inch ID; 33 or 34 teeth (gear is damaged and can’t be sure)

2. Gear as no number printed on it; 2 1/8 inch OD; 5/8 inch ID; 33 teeth?

3. Gear has no number printed on it. 1 ¼ inch OD; .045 ID; 18 teeth.

Can you help or suggest someone who can?

Much appreciated

Al

 

[Joe Michaels]

Al:

A bit of quick math shows your lathe has what are known as "16 pitch" gears (16 pitch refers to the diametral pitch). Finding actual Seneca Falls lathe parts is a very long shot, if you can find someone parting out a Seneca Falls lathe. 16 pitch gearing is quite common. I cannot say what the price would be, but if you look at stock gearing (known as "spur gears) as made by Boston Gear or Martin Gear, you may be able to find replacement gears. Often, these stock gears are sold with a smaller 'pilot bore' thru them. It is then up to the purchaser of the gears to bore them to final size and put in any keyways or set screw tappings required.

You can also check on eBay, making sure to note "16 pitch spur gears". I suspect the Seneca Falls lathes used gearing with a 14 1/2 degree pressure angle, which was more common back when your lathe was built. There are two common pressure angles: 14 1/2 degrees and 20 degrees, so be sure of what you are buying.

Boston Gear used to (and may still) offer 'lathe change gears". These were cast iron spur gears in various pitches/tooth counts.

The other alternative is to have new gears made. The traditional 'one off' method of making spur gears was to use a milling machine, gear tooth milling cutter, and a dividing head. Not the world's most accurate means of making a gear, but OK for an old lathe's change gears or quadrant gears. A more modern method is to find a shop with CNC Wire EDM. They can cut the gears quite accurately from steel plate using CNC wire EDM (CNC = computer numerical control, EDM = Electro Discharge Machining). Another option is CNC waterjet cutting if the right person is programming, setting up and running the waterjet.

The other option is to find an industrial surplus store where all sorts of machinery and equipment and other stuff like fasteners, pipe fittings, odd cutoffs of metal stock, motors, pumps, kitchen sinks, old medical apparatus and anything else is sold. These places have anything and everything at one time or another, no knowing what they have or when. There is an industrial surplus place near me, and they had bins of spur gears for some time (all gone now), and they have bins of tangled together springs, tons of nuts, bolts, socket head screws, random heaps of bearings, old medical equipment, and on it goes. Find a place like that and bring a mating gear to compare and 'roll into' any gears you find in this kind of store.

Other suggestion: get a used/older edition of "Machinery's Handbook" if you want to work with old machinery. A newer edition of Machinery's Handbook is pricier. For basic gear formulas and much else, an older edition will do you just fine. There are empirical or 'cook book' formulas to walk you thru gear design and figuring out what pitch gearing you are working with if confronted with existing/unknown gearing.

 

[Joe Michaels]

On edit:

Al:
If you Google "Boston Gear", you will be able to access their catalog. They still offer "change gears", and offer them in 16 pitch. If you have an industrial supply firm in your area such as Kaman Industrial Technologies (used to be Kaman Bearing), or similar, they should be able to at least give you a price quote on the gears you need. Boston Gear makes the change gears in either cast iron or steel (I suspect Seneca Falls used cast iron, so stick with it). Hub bores and hub bushings are something you may have to work with, either bushing an oversized stock gear's hub bore to reduce it to the size you need, or boring the gear to open up a small hub bore.

Again, I have no idea of what prices are going to be for these gears. Maybe you'd better be sitting down when you get the price quote.

 

[dalmatiangirl61]

If you find the part# in the Boston Gear catalog, do a search for that number on ebay. I've found a few nos gears for projects there for considerably less than new cost.

 

[99Panhard]

Also...look at the threading chart attached to the lathe and see if it has a 33 or 34 tooth gear. It isn't likely to have both and the odd number is very unlikely. You need the gears listed on that chart.

 

[Pease]

Al:

A bit of quick math shows your lathe has what are known as "16 pitch" gears (16 pitch refers to the diametral pitch). Finding actual Seneca Falls lathe parts is a very long shot, if you can find someone parting out a Seneca Falls lathe. 16 pitch gearing is quite common. I cannot say what the price would be, but if you look at stock gearing (known as "spur gears) as made by Boston Gear or Martin Gear, you may be able to find replacement gears. Often, these stock gears are sold with a smaller 'pilot bore' thru them. It is then up to the purchaser of the gears to bore them to final size and put in any keyways or set screw tappings required.

You can also check on eBay, making sure to note "16 pitch spur gears". I suspect the Seneca Falls lathes used gearing with a 14 1/2 degree pressure angle, which was more common back when your lathe was built. There are two common pressure angles: 14 1/2 degrees and 20 degrees, so be sure of what you are buying.

Boston Gear used to (and may still) offer 'lathe change gears". These were cast iron spur gears in various pitches/tooth counts.

The other alternative is to have new gears made. The traditional 'one off' method of making spur gears was to use a milling machine, gear tooth milling cutter, and a dividing head. Not the world's most accurate means of making a gear, but OK for an old lathe's change gears or quadrant gears. A more modern method is to find a shop with CNC Wire EDM. They can cut the gears quite accurately from steel plate using CNC wire EDM (CNC = computer numerical control, EDM = Electro Discharge Machining). Another option is CNC waterjet cutting if the right person is programming, setting up and running the waterjet.

The other option is to find an industrial surplus store where all sorts of machinery and equipment and other stuff like fasteners, pipe fittings, odd cutoffs of metal stock, motors, pumps, kitchen sinks, old medical apparatus and anything else is sold. These places have anything and everything at one time or another, no knowing what they have or when. There is an industrial surplus place near me, and they had bins of spur gears for some time (all gone now), and they have bins of tangled together springs, tons of nuts, bolts, socket head screws, random heaps of bearings, old medical equipment, and on it goes. Find a place like that and bring a mating gear to compare and 'roll into' any gears you find in this kind of store.

Other suggestion: get a used/older edition of "Machinery's Handbook" if you want to work with old machinery. A newer edition of Machinery's Handbook is pricier. For basic gear formulas and much else, an older edition will do you just fine. There are empirical or 'cook book' formulas to walk you thru gear design and figuring out what pitch gearing you are working with if confronted with existing/unknown gearing.

Thank you for your suggestions! Much appreciated!
Al

 

[Pease]

Also...look at the threading chart attached to the lathe and see if it has a 33 or 34 tooth gear. It isn't likely to have both and the odd number is very unlikely. You need the gears listed on that chart.

 

[Pease]

OK I will give it a try. Thank you.

 

[Pease]

On edit:

Al:
If you Google "Boston Gear", you will be able to access their catalog. They still offer "change gears", and offer them in 16 pitch. If you have an industrial supply firm in your area such as Kaman Industrial Technologies (used to be Kaman Bearing), or similar, they should be able to at least give you a price quote on the gears you need. Boston Gear makes the change gears in either cast iron or steel (I suspect Seneca Falls used cast iron, so stick with it). Hub bores and hub bushings are something you may have to work with, either bushing an oversized stock gear's hub bore to reduce it to the size you need, or boring the gear to open up a small hub bore.

Again, I have no idea of what prices are going to be for these gears. Maybe you'd better be sitting down when you get the price quote.

Great suggestion! Thanks.
Al

 

[jim rozen]

seneca falls gear - they can be fixed...:

 

[Pease]

seneca falls gear - they can be fixed...:

Thanks Jim. Any suggestions as to where they might be fixed?

 

[Pease]

These gears are auto feed gears,

 

[Joe Michaels]

Pease:

In response to your asking Jim Rozen as to where the gears might be fixed: Old machine tools like your Seneca Falls Lathe are owned and used (or brought back to operating condition) by people such as yourself and most of us. We keep the old machine tools as we enjoy using them, not too often do we use them for a going business or our livelihoods. As such, a part of owning and working with these old machine tools is being able to repair them or make parts for them. It is sometimes called 'reverse engineering'. This term applies particularly when a part is missing and we have to design a replacement part based on what the missing part must mesh with, engage with, fit into, etc.

If you were to walk into a modern machine shop and ask to have a spur gear like the ones on the Seneca Falls lathe repaired, unless you ran into a kindly and understanding shop, you'd be told: "We do not take on small jobs like repairing old lathe gears"
or: "We can design and make you a new one, but it's gonna cost you some big bucks..."

Machinists and shops doing these sorts of repairs for walk-in home shop people are almost extinct. Your hope is to find someone in your area who is also a home shop machinist or retiree with a home shop. Or, watch youtubes of Pakistani machinists and truck mechanics. Those guys repair truck transmission and rear end gears by building up busted teeth with stick welding and shaping the repaired teeth with angle grinders and a good eye. How long those repairs hold together in service in overloaded trucks on bad roads is never the subject of the youtubes.

All kidding aside: look at the repair done to the gears Jim Rozen posted pictures of. The busted teeth were filed down to the roots. Small holes were drilled and tapped into the rim of the gear on the centerline of each busted/missing tooth. Steel studs (possibly longer hex-head bolts) were driven into the tapped holes. The un-threaded shanks of the bolts were then filed to the shape of the tooth. No fancy machine shop, no specialized tools. A vise, a few files, square, scriber, prick punch and drills and taps... and some patience and care and a good eye and good hand with a knife-edge file to shape the tooth profiles. Put some Prussian Blue or even a thin coat of grease on a good gear and 'roll it in' against the repair. This will show tooth contact. File lightly and carefully until correct profile and good tooth contact is had. The beauty of this repair is that, if you screw up (sorry about the pun), you unscrew the 'tooth' made from the bolt, and screw in a new bolt to start over. I'd run the bolts in as tight as I could without stripping the threads I tapped, maybe use some Loctite, and then cut the excess bolt shank/head off with a hand hacksaw. The rest is done by filing.

The alternative repair method is to build up the areas of the busted teeth with bronze brazing using an oxyacetylene torch. When cooled, brazed area is shaped to create replacement teeth using a hacksaw to start the 'gullets' or 'valleys' between the teeth, and then filing.

These two methods are classic methods for repairing busted gear teeth. The beauty of the brazing method is that the bronze brazing metal will give you enough material to create 'full teeth'. The other beauty of it is that the bronze metal is relatively soft and will 'cold form' to final tooth profile when 'run in' against the iron teeth on the mating gears. This 'cold forming' will work harden the bronze and burnish the repaired teeth to a good finish. Cautionary note here: you have to file the teeth to something quite close to correct spacing and profile before attempting to 'run in' this sort of repaired gear teeth.

I'd suggest you get some familiarity with the basic parameters and equations for figuring 'spur gearing'. When you have learned a bit about gear tooth geometry and terminology, you then follow Dalmatian Girl's suggestion of browsing eBay for gears. In my post, I determined your lathe has '16 pitch' gears. You need to do some careful measuring of the actual outer diameters. On gears with missing teeth, if you know the actual outer diameter and the pitch, you can work the equations to get the number of teeth. No guesswork. It is unlikely you have a 31 tooth gear, as 31 is a prime number (divisible by itself and 1). Lathe change gears usually have some number of teeth which is evenly divisible to give ratios in 'whole numbers'. The exception to this is the change gears needed to cut metric thread pitches on a lathe with a lead screw having threads in a pitch based on inches.

Again, if you do find gears that are 'stock', you will likely have to modify them to fit your lathe's studs (where the feed gears mount). You may have to bore the hubs of the stock gears out to fit tour lathe's studs, or you may have to make bushings if the bores in the gears you find are too large. You use your lathe for this, hand feeding the tools. It's reverse engineering. You are equipped with the most incredible gifts for this sort of thing, to do the reverse engineering and to do the repairs by methods as shown by Jim Rozen. Those gifts are your mind, hands, and your eyes. Use them.

 

[99Panhard]

If you can, please post a photo of the threading chart...it should be a plate, probably brass, attached to the lathe head stock that lists the gear combinations for each thread.
A quick look at the Boston Gear catalog does not show any 16DP gears with 33 or 34 teeth...they skip from 32 to 36. That only means it might not be easy to find one but, as Joe has pointed out, you are not likely to find someone who can repair the gear and, if you did it would be very expensive. It's fussy, time consuming work and no one is doing it for $1.00 and hour.

It's clear you don't know much about gears...the tooth count and the DP (Diametrical Pitch) determine the size so any 16DP gear with the correct number of teeth will fit. Again, as Joe M has pointed out, the hole in the center may have to enlarged or reduced but this is relatively simple lathe work that can be done with the machine unless one of these broken gears is part of the drive train. If so, that is a job that you may well be able to get someone to do just to get operational. The change gears are only needed for threading.

I have some loose change gears...tomorrow I'll check the DP and see if they are 16...I think they are either 16 or 18 and came in a box of miscellaneous parts that I will likely never use.

 

[jim rozen]

This is not his threading chart, but it is *a* seneca falls threading chart:

As mentioned the gear I showed above is the pick-off gear for feeds, sits at the end of the spindle. I re-did this gear from scratch, also the smaller back gear as well. You can see the pins in that one, barely. All these pins were straight pins, pressed in, and filed to rough approximation of the tooth form. I saved all the repaired pieces as the worked well and are a bit of history. The lathe itself is a long term resoration project. Keeps me off the streets at night.