Made Some Big Threads

[Kevin T]

Big = Relative I know!

I am going to make a new spindle collar for use with my collets. The one I'm using is really ugly to look at and so away I go.

Until I am better, could be never, at using the machinists handbook to understand all the ways to measure threads I feel much better having a test thread in hand to check for fit.

So I made a male threaded part with 2 3/8-6 threads as a first step. I didn't respect the extra forces involved in cutting this large of a thread and ended up breaking the Aloris insert! Nice 52 dollar mistake. Sort of lucky that I am on a belt driven lathe too! Got a little slip in the second and a half reaction to shutting her down!

Anyway they turned out really well after some clean up so I figured I'd start a thread to hear of others adventures with "big" threads...and the anticipated "you think that's a big thread son" discourse that I enjoy! "Why back in my day we single pointed rail road wheel shafts and screwed 'em on and sent them off to war!"



Next to the collar I plan on making next.



Perfect fit



I need to find a nice safe place to keep this puppy since I may have a need for a spindle thread ref in the future.

 

[Bonecca]

Thread it into your unused chuck. It will protect both threads that way and you will know where to find it when needed.

 

[michiganbuck]

Nice looking parts you made.

QT: [I am going to make a new spindle collar for use with my collets.]

A chuck-held collet holder may also be considered, perhaps to collet larger parts

Having .003-.005+ error or wobble out of your best chuck then the in-the-chuck finishing may be best for less error than that.

You need a very good line-up mark, perhaps a deep scribed line on a certain jaw face, and a how-deep in the chuck line or shoulder step.

Yes, the line-up line device can only be used in that one chick.

True, out of the lathe taper and a step up diameter can suffice larger collets/parts.

 

[GenePoole]

I've made a number of accessories for my SB13 spindle and I guess during the first attempt, I discovered early on that a thread gauge would be a lot easier to make than to keep pulling the work-piece off to test it only to find that I still needed a few thou to go, then re-chuck and pick up the thread.

I've made a number of thread gauges over the years. It's pretty easy when you have a good set of thread wires to measure.

Probably the biggest thread I did was for a filler neck for an aluminum fuel tank. I can't recall the exact size (it was metric) but I had to grind a pretty big thread tool from HSS.

 

[Kevin T]

Nice looking parts you made.

QT: [I am going to make a new spindle collar for use with my collets.]

A chuck-held collet holder may also be considered, perhaps to collet larger parts

Having .003-.005+ error or wobble out of your best chuck then the in-the-chuck finishing may be best for less error than that.

You need a very good line-up mark, perhaps a deep scribed line on a certain jaw face, and a how-deep in the chuck line or shoulder step.

Yes, the line-up line device can only be used in that one chick.

True, out of the lathe taper and a step up diameter can suffice larger collets/parts.

I have the 5C collet holder (sleeve?) that indexes my collets in the spindle bore. The collar I am making is the nut that keeps it in check. The one I have works but is an eye sore. One of the spanner holes is blown out and bugs me to look at. I suspect it is shop made but I'm not sure. It looked worse when I got it. The knurl pattern extended to the front chamfer edge and was wasted.



I thought about boring a nice shallow hole in it and pressing in a plug to face and drill a new spanner hole but then I wasn't sure if/how I needed to fix it in there and punted to make a new one.

 

[Kevin T]

Got the hard part done. Took me a while to figure out a setup to cut these threads since I didn't want to use my WWII boring bar. It flexes too much for my taste. I rummaged in my pile of things I got with the lathe and found this lantern style 60 deg thread tool. The shaft of it wasn't square and I had to shim it in a QCTP holder but it worked.



I had to run way in on the CS to use the thing with very little clearance at max depth so it was slow going.



My spindle collar is nearing completion after today. The check thread was very useful.

 

[Greg Menke]

Glad I'm not the only one cozying up to the lathe on a long winter's night... likewise making a spindle master, 2 3/8-6 with a long register and some taper. Just got a spiffy 3 jaw chuck that I need to make a backplate for. I think your material machines a lot nicer, mine is gummy and soft like 1020 but at least it doesn't work harden.

 

[LKeithR]

Are flip-flops approved safety footwear in Hawaii?

 

[Kevin T]

Glad I'm not the only one cozying up to the lathe on a long winter's night... likewise making a spindle master, 2 3/8-6 with a long register and some taper. Just got a spiffy 3 jaw chuck that I need to make a backplate for. I think your material machines a lot nicer, mine is gummy and soft like 1020 but at least it doesn't work harden.

I am using some 1018 Cold Roll Steel that I got from ebay. I got a 3.5 OD x 7" long piece for 60 bucks with 16 dollars shipping. I couldn't really afford anything else. The material has inclusions in it so it's not that wonderful either. You'll be going along nice and then hit a vein of something that interrupts the nice chips you were making. Interesting while threading internally! Couple more passes and then the "rough spot" moves down the part a little.

I hope I can make the OD look nice. I have a variety of cutters to try so I'm optimistic. The male threaded check part I made was 8620 steel and was much nicer to machine but I couldn't find any in larger diameter than say 2 1/2.

When I've encountered gummy metals I normally switch to a pointed HSS cutter and that seems to help.

 

[Kevin T]

Are flip-flops approved safety footwear in Hawaii?

Ya know... it's funny how often I am machining in flip flops; basically everytime... (we call them slippers or more correctly "slippahs")...and I catch a hot chip on my foot quite regularly. I can hide behind the saddle most of the time if I am throwing chips around. I am sure this sounds terrible to a seasoned machinist but I am very careful with my actions and movements. I am not making money with my lathe just passing the time doing something that I enjoy. Slow and steady and most often...predictable.

 

[dullvinci]

Making a threaded plug gauge to match the spindle thread is definitely the way to go, because it has so many potential uses. My suggestion for sizing is one that I have used many times but may be frowned on by many machinists. That is single wire thread measurement. No need for sets of thread wires, easy to do without juggling three wires and a mike, and accurate enough for the majority of threading jobs. Ideally the OD of the new thread should be the same as the thread being duplicated, but not necessarily. If the new thread is bigger or smaller than the original, just add or subtract the difference in radius to the measurement. Try it, you'll like it.

 

[michiganbuck]

Single wire seems fine/OK if you have an existing thread to measure from/to.

The point of three wires check is that you can figure out a thread or look up the numbers in a reference book.

(I'm just mentioning that for the new guy her as likely you that.)

I used to hand feel a male to female thread fit, but now I understand that hand feel fitting can be wrong because of heat expansion, the thread may not go together/ be too tight.

Your work looks very good.. do you get any work/money cutting threads/ lathe jobs?

 

[Greg Menke]

I am using some 1018 Cold Roll Steel that I got from ebay. I got a 3.5 OD x 7" long piece for 60 bucks with 16 dollars shipping. I couldn't really afford anything else. The material has inclusions in it so it's not that wonderful either. You'll be going along nice and then hit a vein of something that interrupts the nice chips you were making. Interesting while threading internally! Couple more passes and then the "rough spot" moves down the part a little.

I hope I can make the OD look nice. I have a variety of cutters to try so I'm optimistic. The male threaded check part I made was 8620 steel and was much nicer to machine but I couldn't find any in larger diameter than say 2 1/2.

When I've encountered gummy metals I normally switch to a pointed HSS cutter and that seems to help.

Cool. In my misc pile I found a perfect sized piece of 3" unknown stuff obtained from a basement cleanout. Magnet stuck to it, file cut it... good enough. Threads will be HSS anyway.

 

[dullvinci]

Michiganbuck
I forgot to include a caution on one wire measurement. Depending on cutting tool and material, the threading tool can throw up a burr which affects the measurement. I use a smooth file on the side opposite the wire to remove it. This is Not a factor when using three wires.

 

[Kevin T]

Finished! Finally... I took some design cues from GenePool and made a thread master for my spindle and improved the part with three spanner holes 120 deg on center instead of the two in the original part.





Finally have a use for the fugly printed part I got to protect my lathe spindle during the refurb!

 

[plastikdreams]

Biggest I've made to date single point was 1.75 nh thread. It was an adaptor to block the end of fire hose and still attach a nozzle, then fill the hose with compressed air to simulate the feeling without getting water all over the inside of the firehouse.

 

[michiganbuck]

Michiganbuck
I forgot to include a caution on one wire measurement. Depending on cutting tool and material, the threading tool can throw up a burr which affects the measurement. I use a smooth file on the side opposite the wire to remove it. This is Not a factor when using three wires.

Oh. one wire and then measuring over to side opposite.. that does not seem a very close way to measure.

 

[Kevin T]

I am afraid to measure this latest work with wires, I might not be able to call it a thread master! lol
I hit my major and minor diameters closer than anything I've done yet. <.001 on both! Not bad considering I had to switch back and forth between my 3 jaw and 4 jaw to get the job done. My 3 jaw has a 2.50 thru hole in it so it was useful for the big threads.