Spindle Thread Protector

[mcload]

Just thought I'd post some photos of a spindle thread protector I made from a 1.5 x 8 steel nut.
The nut was pretty darn cheap. I took a couple of days to do this, taking my time. I knocked off the peaks
then put a 50-degree angle on one side. I then attempted to put a knurl on the shoulder, but it's not a very
good one. Cheap import tool I think, plus steel is not very malleable.

I used a parting blade about ¾ through the nut then finished with a hacksaw. Turned it around and faced
the shoulder side, then a .25 deep removal of the threads with a boring bar. This space allows the protector to
extend over the portion of spindle that is not threaded.

All in all, it turned out okay. Guess I could finish it a little better sometime.

PMc

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[texasgeartrain]

Real nice.

Is this for using collets ? If so, do the collets go directly into the spindle taper, or is there and adapter ?

Reason I'm asking, is I see just a touch of spindle thread sticking through. Was curious if possible to add a washer, or spacer to back side, be it loose or tach welded or whatever.

Then it occurred to me that my nose adapter has a smaller ID at nose end. Presumably to help pop spindle adapter off when its tight in the taper, by loosening the protector into the adapter and allowing it to put some pressure on adapter. (atleast that's how I use it )

Not sure how your setup is, but adding a spacer to either side, and/or maybe dealing with popping what's wedged in the taper may be something useful. Just food for thought, but your intended use is the main factor.

 

[Kevin T]

That looks pretty good! Just a thought, if it is for collets, is that sometimes that collet sleeve gets stuck after use so I have to use a wrench on the thread protector to get it off....hence holes in the side for a spanner. I wanted to do this, like you with a nut but I couldn't find a 2 3/8-6 nut! So I ended up buying an ugly one off ebay and cleaning it up with some fine cuts.

 

[mcload]

Spindle Collet Adapter on a 9" Lathe

Yes, you are both correct. The "thread protector" is more predominantly used to push the collet spindle adapter
out of the short MT3 taper in the spindle (9" lathe). In the photo below, and using the bonafide SB part, you can see the hole
where a pin wrench is used (if necessary) to push the adapter out. In all actuality, the handle end of a Jacobs chuck
key works just as well in most cases....it's rarely in there very tight. (You can always use a knockout tool through the spindle should it not budge)

The spindle adapter sticks out quite a lot when in position and I guess you could fit a Delrin washer to reduce this distance,
but there is plenty of thread to use on the collar to push it out. I guess one less piece to have to keep up with...or to lose. (The collet is placed in the adapter loosely in the photo just to show the flare)

I have three of these male spindle thread tools in the bottom drawer that I have never used. Actually, I believe these are used
to hold a very small 4-jaw chuck in the tailstock for whatever reason. But I used the one in the foreground with the half-inch shank to
hold the big nut for turning. Hindsight being 20-20, I now wish I had used my bigger and more robust chuck to hold the nut directly.

It worked okay as I was taking very light cuts at dead slow back gear speed; I was in no hurry. But for the final .005
finishing cut at a higher speed (no back gear), I was getting quite a bit of chatter. Yes, could have been the lack of having a sharp tool and/or having the wrong amount of rake on the HSS bit, but I think it was more because I was holding the half-inch shank.
I later (and reluctantly) positioned the piece in the 3-jaw chuck on the outer shoulder. Not much to grab hold of, but it improved cutting, especially for the 50-degree taper. (I assume these are commercially available; don't know offhand)

In all candor, I have yet to drill the 5/16" hole for the pin wrench in my new piece. I figured I would use the saddle tool in the tailstock to at least get a small pilot hole started in direct center of the piece...if I can find the damn thing. From there I'll use the drill press to finish the hole, though it spins far too fast for steel in my opinion. Easy does it is the name of that game.

I was bidding on a SB thread protector / spindle-adapter-pusher-outer last week but the bids got into the nose-bleed area and I backed out. Hence, I made my own. It's only a bit shorter than the real thing, but good enough for govt work!

Thanks.

PMc

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[texasgeartrain]

In double checking mine, the ID of protector at nose tip is not smaller than the threads. I must have mis-remembered that . Its just threaded through like yours.

In nut to adapter ratio size wise, the OD of your adapter's outer collar is larger too. You have more meat to push from.

The OD of my adapter is just slightly larger than the tall portion of threads. . . Which in examining that closer I'm surprised the threads of protector have not mushroomed. I'd probably put that down to not an everyday worked item.

Out of curiosity, what collet type does your adapter hold ?

 

[mcload]

In double checking mine, the ID of protector at nose tip is not smaller than the threads. I must have mis-remembered that . Its just threaded through like yours. In nut to adapter ratio size wise, the OD of your adapter's outer collar is larger too. You have more meat to push from.
The OD of my adapter is just slightly larger than the tall portion of threads. . . Which in examining that closer I'm surprised the threads of protector have not mushroomed. I'd probably put that down to not an everyday worked item.

Out of curiosity, what collet type does your adapter hold ?

They are size 3C collets. I think the only original part in the set below is the spindle adaptor.
SOUTH BEND 9 INCH LATHE COMPLETE 3C COLLET SET USA PARTS + 7 PC IMPORT COLLETS | eBay

PMc

 

[Kevin T]

Did you consider annealing the nut prior to machining to soften the material and make it easier to cut?
Would it have helped?

 

[mcload]

Did you consider annealing the nut prior to machining to soften the material and make it easier to cut?
Would it have helped?

No that never occurred to me. If it had refused to cut at all, then I would have known it was hardened.
I just took it for granted that it wasn't...probably naive on my part. Are all nuts hardened just as a matter
of manufacturing? I've never known steel to be very easy to cut anyway...pretty sure it was my crappy bit.
And let's face it, a 9" isn't known as a heavy machine for hogging out steel to begin with.

 

[texasgeartrain]

No that never occurred to me. If it had refused to cut at all, then I would have known it was hardened.
I just took it for granted that it wasn't...probably naive on my part. Are all nuts hardened just as a matter
of manufacturing? I've never known steel to be very easy to cut anyway...pretty sure it was my crappy bit.
]

Anything can be hardened or not. In general hardware is rated by grade of steel, like grade 8 and such. Which I would say is un-hardened. Think how you can round off a bolt head, or mushroom it by giving it a whack with a hammer.

I believe the nut and stud for something like an Aloris tool post is hardened, while the tee nut is not.

Hardened hardware will tend to break verse distort like regular hardware.

I feel pretty sure you would never have cut your nut so nice if it was hardened, plus you put knurling tools to it.

Also with heat treating you'd have to deal with growth and /or some distortion ie the threads could end up slightly different so as to not screw on so cleanly.

As far as finish, sometimes I experiment with different tools and speeds before getting to finishing pass. Recently I was cutting mystery unknown steel. Trying various tools and speeds, I had to crank speed up to 1000 rpm and my best finish was with brazed carbide, over both hss and insert tooling.

 

[SLK001]

The "thread protector" is more predominantly used to push the collet spindle adapter out of the short MT3 taper in the spindle (9" lathe).

You'll find that the thread protector comes in handy when working between centers, too.