Barnes 4 1/2 Spindle (Gear End) Threading

All, as title suggests, I'm looking to replace the nut that holds the gear(s) on the back of the spindle and cannot find my thread gauges. Diameter at threads is .589.

Thanks very kindly!

Philosophy Guy said:

All, as title suggests, I'm looking to replace the nut that holds the gear(s) on the back of the spindle and cannot find my thread gauges. Diameter at threads is .589.

Thanks very kindly!

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Reading 0.579 over the thread tops, the actual shaft may indeed be 0.589.

The TPI is 16. You can confirm this like I did by holding a 3/8-16NC bolt alongside.

You'll be making the nut to fit, of course. If you're using the lathe, a tie-wrap could fill in this spot and hold the gear nicely

Good luck.

Joe in NH

In other words, not something you can buy.

Victor Machinery Exchange may be able to make the required tap without taking out a loan

The closest they get in their Special Taps list is 19/32 - 20

Thanks, gents!

I measured/guestimated 16 tpi since my post, and figured it would be a custom make.

The tie wrap is a great idea. I was thinking maybe a stiff stretched o-ring, as I've tested it and there's not a lot of walk or wobble, even without a nut there.

Guess I've got one of my first projects!

Thanks again,

Dan

Spindle nut

I took some photos of the spindle nut on my 4-1/2 to give you an idea what you might want to do. It should not be too difficult of a project.

stef. said:

I took some photos of the spindle nut on my 4-1/2 to give you an idea what you might want to do. It should not be too difficult of a project.View attachment 309643View attachment 309642View attachment 309641

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On my 4-1/2, the nut is an actual hex nut. 15/16 on the hex, 0.320 thick.

There also is a keyed spacer to fit the 0.590ish main spindle - and used for setting up/managing "compound" gearing. Bushing to be put on alongside the gear and simply occupies the position not used.

Also below this the "stud" which includes a bushing that the gear and spacer or two gears can mount on. These held by a different looking large headed hex bolt. (seen as a "knurl/thumb-nut" on the pix above.)

Another of the same large headed hex (Knurl?) bolt is used on the lead-screw position to hold the lowermost gear, but no bushing/spacer, and no place provided for one.

I see in the pix above, the gear train IS set up for compound gearing. I don't think I've ever used compound gearing myself.

I think actual parts "varied" in Barnes lathes. "Made to fit" was used a lot. The large hex nut mentioned is not from this lathe but from a "donor" 4-1/2 lathe, and on this lathe the thread is a little "sloppy" compared to what I might make myself. Interchange of Barnes parts does open the possibility that the fit is not "original." Still, for me the hex nut "works."

Joe in NH

Compound gearing

The compound gearing started when I needed a 3/16-30 thread on a turn of the century knurled thumb screw. The thread chart on my Logan would not offer that thread size. In looking over the thread chart on the Barnes 4-1/2 it showed that it would allow me cut 30 tpi. If you follow the chart correctly and have a very sharp tool, the 4-1/2 will give excellent results in cutting the thread. Also in compound gearing, the large 88 tooth gear holds the leadscrew in place without a screw or bushing . Sorry, I didn't mean to highjack the post.

George

stef. said:

Sorry, I didn't mean to highjack the post.

George

Click to expand...

No hijack. Just describing "experiential use" - which we're all eager to hear.

I can see how the gear positioning might "pin" the 88 gear in place. Your lead screw IS drilled for the keeper bolt is it not? But its use might not be mandatory for this particular setup.

Joe in NH

Keeper screw

The keeper screw has to be removed from the leadscrew for this gear train setup (30 tpi) to function. (Make sure you put the keeper screw in a safe place they would not be fun to reproduce.) Since the 88 tooth gear overlaps the leadscrew gear it would not let the 88 tooth gear mesh with spindle gear with the keeper screw in place. It was a real head scratcher when first experimenting and trying to compound the train of gears. I have included a photo of the keeper screw .297-18. All of the screws holding the gears in place have knurls on the heads probably for convenience with no need for wrenching the gears down. I do not know when my 4-1/2 was manufactured but the knurl on the screw head would help with a time study.

Thanks as ever, gents!

Mine is definitely set up for compound gearing, and the plate indicates not only what gears to run for what TPI you want, but how to stack the gears.

The 88 always runs (I think?), but can go over or under the other gear.

As Stef notes, the keeper isn't needed if the compound places the 88 at the outside.

However, the knurling on my keeper screw runs the other direction, for whatever that's worth.

I'm out of luck making the part, however, as I have only four change gears, and am missing one (32) for that tpi. Looks like I'm missing only nine to make the complete set!

In fact, as Murphy would have it, looks like I'm missing all of the really important gears for most kinds of threading.

I can, however, run one tpi. The most the most common, and most important.

154.

So there's that consolation prize.


Well, guess I'm either in the market for some gears, or ... some gears. Or something.