New to the board, new to me 9 junior and new to machining

[bigblock61]

Hi all,

I recently picked up a south bend 9 junior lathe for a great price. I'm cleaning it up and making it work again. I'm new to this so there is a lot lo learning for me. That's one of the reasons I joined this site. I'm hoping to learn about my lathe and how to make things.

A little about myself. I was a Master Mechanic for 25 years before deciding to become a Network Engineer. I am currently restoring and modifying a 1969 Dodge Coronet. when it's done it will have a Dana 60 rear end, 6 speed manual trans out of a Viper, and a 512 cubic inch engine with a six pack intake. I say all of this to let you know that I am comfortable as a fabricator and builder. My ex father in law was a machinist for a steel mill and first got me interested in creating parts.

The one thing Id like to be able to do is cut threads with this lathe. Unfortunately it didn't come with the change gears. I've been looking online for the gears but not sure what I need. The chart on the gear cover references a stud gear and a screw gear. I figure that the screw gear is the one attached to the lead screw. The stud gear must be the one mounted on a stud attached to the banjo. This is a double gear at 81/18. Do I need to look for other double gears and in what sizes? Like a 32/ 18 or maybe an 81/32. I cant seem to find any information on the change gears for this particular lathe. Can anyone here help?

John

 

[iwananew10K]

stud gear is the one on the reverser lever...it's the first gear going from the spindle down that has a nut holding it on.

 

[Doc Hoy]

John,

Welcome to the group. I was just wondering if you had bought some stock in BP or Shell. ;o)

You and I are in the same boat WRT lathes. I just finished the paint job on mine and posted photos.

A very kind gentleman on the forum sold his set of thread gears to me and you may find others who have the set.

I have worked Grizzly tools for about 25 years and like them for the price and the general quality. But now that I am using this South Bend, I see there is no comparison.

The tool post I bought from eBay for just over a hundred bucks, works great. You have to make a smaller base plate than comes with the set but it is no problem. Also bought a MT2 Jacobs chuck from an eBay seller. It works great as well.

Best of luck with the Super Bee and the South Bend.

 

[iwananew10K]

Kitno455 is really the guy for the jrs, but IIRC it takes standard off the shelf 16DP change gears.

Do you need the change gears?

 

[kitno455]

right, the 9Jr uses 16DP, 14.5PA, .5 face width, 5/8 bore gears. These are a standard item for makers like Boston Gear, but it would cost a small fortune to assemble a complete set that way. You are better off if you can find an original SB set, it will typically cost less.

allan

 

[bigblock61]

Ok After reading I'm a little more confused. From the top there is the spindle gear then the 2 forward and reverse gears a small double gear below that then another double gear that is attached to the banjo that I am calling the stud gear and is a double gear then finally the screw gear that attaches to the carriage screw. which gear is which for chance gears?

There is this part of me that just thinks I should make them. I'm already working on a vertical cross slide so I could mount the gear blank vertically and put the cutter in the lathe chuck. I'm still working out a reliable degree wheel that could be mounted on top. a 32 tooth gear that is 16 pitch is 2 1/8th around and the teeth would be spaced out at 11.5 degrees. It's that 11.5 that is tripping me up right now.

 

[bigblock61]

Kitno455 is really the guy for the jrs, but IIRC it takes standard off the shelf 16DP change gears.

Do you need the change gears?

Yes I'm looking for change gears. At least the 16, 32, and 64 stud gears then one or two to start me off cutting a screw pattern. It would be nice to have the 32 screw gear so I can do 8tpi threads to make a chuck backing plate.

 

[bigblock61]

John,

Welcome to the group. I was just wondering if you had bought some stock in BP or Shell. ;o)

You and I are in the same boat WRT lathes. I just finished the paint job on mine and posted photos.

A very kind gentleman on the forum sold his set of thread gears to me and you may find others who have the set.

I have worked Grizzly tools for about 25 years and like them for the price and the general quality. But now that I am using this South Bend, I see there is no comparison.

The tool post I bought from eBay for just over a hundred bucks, works great. You have to make a smaller base plate than comes with the set but it is no problem. Also bought a MT2 Jacobs chuck from an eBay seller. It works great as well.

Best of luck with the Super Bee and the South Bend.

No, no stock in BP or Shell but that would make things easier for the Coronet build. Thankfully I was able to find the rear end and trans fairly cheep. I build it when I am able to throw money at it, so I guess it will be done the day after I die lol.

 

[iwananew10K]

FYI- as noted, gears are 16DP with the specs as per kitno455.
good deals can pop up if you know what to look for.
you just need to know the formula for gears is-

tooth count + 2 divided by diameter = DP (diametral pitch)

so a 30 tooth gear with a diameter of 2.00" is 16DP

30+2=32
32 div by 2= 16

sometimes unidentifed gears pop up on ebay cheap(relatively), you can ask a few questions and come out good.

 

[kitno455]

The 'small double gear' you mention is two pieces. The inner gear stays attached to the reverse tumbler, and you'll note- has the same number of teeth as the spindle gear. The entire train is 1:1 at that point. The outer part is the removable stud gear. The gear below that is an idler or compound. You happen to have a compound there, for low speed turning. When threading, you'll use that gear as an idler, by moving the screw gear inboard. There is a spacer under it that you swap to the outside.

allan

 

[bigblock61]

The 'small double gear' you mention is two pieces. The inner gear stays attached to the reverse tumbler, and you'll note- has the same number of teeth as the spindle gear. The entire train is 1:1 at that point. The outer part is the removable stud gear. The gear below that is an idler or compound. You happen to have a compound there, for low speed turning. When threading, you'll use that gear as an idler, by moving the screw gear inboard. There is a spacer under it that you swap to the outside.

allan

Morning kitno455, not to beat a dead horse, I'd just like to get this straight in my head. I have attached a picture showing what I now believe to be the stud and screw gears for threading. Let me know if I got it or not. This would make some of the change gear sets I've been seeing online make more sense.

 

[kitno455]

Yes, that is correct- though note that when threading, you need to use the large side of the compound as an idler only.

allan

 

[bigblock61]

Yes, that is correct- though note that when threading, you need to use the large side of the compound as an idler only.

allan

Got it, thanks for all the help. I went out this morning after posting and took the gears apart to see how they worked. It all really makes sense now. Now I just need to find some SB change gears. I heard that a heavy 10 will have the same gears.

 

[iwananew10K]

did you get the PM i sent? it would be hard to beat that if they are correct.

 

[bigblock61]

did you get the PM i sent? it would be hard to beat that if they are correct.

Yes I got it and contacted the seller. I hope to hear back soon and thanks for sending me the link.

 

[iwananew10K]

re- back plates....,you have to really just want to make your own because it's actually cheaper to just buy them, nothing wrong with rolling yer own tho.

If you want to buy them I have found the Shars plates to be plenty decent.

 

[bigblock61]

did you get the PM i sent? it would be hard to beat that if they are correct.

just heard back from the seller and they are 3/8 thick. They wont work on mine.

 

[bigblock61]

re- back plates....,you have to really just want to make your own because it's actually cheaper to just buy them, nothing wrong with rolling yer own tho.

If you want to buy them I have found the Shars plates to be plenty decent.

I want to make everything right now. It's not about the cost, it's about being able to make something.

 

[iwananew10K]

I can certainly understand that.

It may be good to post a wanted to buy ad (in the WTB/For sale section)
for the gears- lots of guys have piles of them laying around and 16DP is about the most common of all.

 

[bigblock61]

It was a Christmas weekend here for the South Bend I got a quick change tool holder, a set of carbide bits, A 4 inch 4 jaw chuck used, and a bunch of HSS and carbide cutter blanks. The belt I ordered was too small. I goofed and measured the original belt from the short end and not what was wrapped around the pulleys. That one is on me so I need to order another one. 9 Junior is starting to become useful and I may actually be able to turn something soon.