14" Reed prentice model b lathe broken drive gear questions.

[fastguyjosh]

Hi all,
I've followed many of these threads and have turned to this site on countless occasions for all kinds of things. It's amazing what networking can do. I want to start off by saying thanks. Now onto the real topic. I have a early 40's Reed prentice 14" model b lathe and its missing three teeth in the smaller gear. The best i can tell is that it's part H65 in the microfiche or parts breakdown from the manual. I'm hoping to gain knowledge of where to possibly look to get a replacement and if there's such a thing as a machinery "salvage yard" that may have one. I know a bunch of them were made so i feel like the possibility of coming up with what I need is possible. Lever c is the actuating lever that engages either of the two.. It's the small gear that lost the the teeth. I want to say there's only 12 teeth on it. It's been a bit since I had it opened up. Thanks for your help. Josh.

 

[johnoder]

Hi all,
I've followed many of these threads and have turned to this site on countless occasions for all kinds of things. It's amazing what networking can do. I want to start off by saying thanks. Now onto the real topic. I have a early 40's Reed prentice 14" model b lathe and its missing three teeth in the smaller gear. The best i can tell is that it's part H65 in the microfiche or parts breakdown from the manual. I'm hoping to gain knowledge of where to possibly look to get a replacement and if there's such a thing as a machinery "salvage yard" that may have one. I know a bunch of them were made so i feel like the possibility of coming up with what I need is possible. Lever c is the actuating lever that engages either of the two.. It's the small gear that lost the the teeth. I want to say there's only 12 teeth on it. It's been a bit since I had it opened up. Thanks for your help. Josh.

Yep - shaft with gears as part of shaft. Either exact right replacement part or make from scratch - with all the attendant heat treat. A start would be to have it out and make a drawing with each and every double checked dimension - including exact gear tooth detail. The piece itself has three bearing fits and a thread and its "key way" for the lock nut and its tooth type locking washer.
I see both sets of gear teeth are marked 10P with the big one saying 31 T as a guess. Can't read number of teeth on the small one. 10 P really means 10 Diametral Pitch

 

[fastguyjosh]

Yep - shaft with gears as part of shaft. Either exact right replacement part or make from scratch - with all the attendant heat treat. A start would be to have it out and make a drawing with each and every double checked dimension - including exact gear tooth detail. The piece itself has three bearing fits and a thread and its "key way" for the lock nut and its tooth type locking washer.
I see both sets of gear teeth are marked 10P with the big one saying 31 T as a guess. Can't read number of teeth on the small one. 10 P really means 10 Diametral Pitch

Thank you. I was hoping to not take it down twice but i may have to. Even having the capability of making it, and heat treating it I'd still have to source the grinding for the bearing fits. Which isn't the end of the world but if i can have a good used one in my hands my down time and labor would be tremendously less. The lathe runs exceptionally well for it's age i just don't have half the speed's. Which isn't the end of the world either. Thanks for the info. Josh.

 

[johansen]

Hard turn the teeth off, Find a gear sufficiently wide, bore it out, press it on, followed by a sleeve for the bearing to ride on. Loctite and or pin the sleeve, then thread the sleeve. If you get lucky then you can save the stock threads at the end. (Looks like it's just a bearing retainer). You could also drill and thread the end and use a bolt and a washer.

If you don't trust loctite to hold the gear, drill a keyway with a 1/8 or 3/16" carbide drill bit (assuming it's too hard for hhs) and tap in a roll pin, or two, or 4...


Regarding concentricity. If you want to get better than .001".. hard turn off the gear teeth very carefully, while holding the existing bearing bore in a steady rest. Then drill and bore the shaft so you can hold it in your tailstock, remove the steady rest and turn the shaft down so the new gear can be pressed on.

Find 6 dowel pins of a diameter that can fit in the teeth. Measure across the pins, turn and bore a ring that can be lightly pressed over all 6 pins. Then hold that ring in a steady rest while you touch up the sleeve you pressed on, then turn threads on the end of the sleeve to hold the new (or old) lock nut.

You may get lucky and if you are off by half a thousandth in one direction, pull the gear, rotate it quarter turn and press it back on, this would remove the need for any touchup operations.


I'm assuming you would hold the left end of the shaft in johnoders post by the inside in a 4 jaw chuck, while using a pin set in the gear teeth to measure concentricity. This can be a pain in the ass. I recommend 4 identical pins held in the teeth with rubber bands.

If it's a helical gear you will have to find some other way to hold the shaft on the pitch circle. Perhaps trusting that the outer edge of the gear teeth is concentric to the pitch circle is good enough...

 

[johnoder]

Thank you. I was hoping to not take it down twice but i may have to. Even having the capability of making it, and heat treating it I'd still have to source the grinding for the bearing fits. Which isn't the end of the world but if i can have a good used one in my hands my down time and labor would be tremendously less. The lathe runs exceptionally well for it's age i just don't have half the speed's. Which isn't the end of the world either. Thanks for the info. Josh.

Here are the Timkens and their cone bores (that fit the shaft)
17118 / 1714
cone bore 1.1806"

368 / 362A
cone bore 2.000"

3190 / 3120
cone bore 1.1811"