Captured allan bolt locking lever

[Canobi]

As a guy who has finished 42+ years in the machine shop, I love what you are doing, except for one thing. I cringe when I see anyone wear any type of gloves around a lathe. I personal like the type of gloves you are wearing, and have many worn out pairs in a box in my shop.
My cringe come from the witnessing of too many fingers, hands, pulled off the body by a lathe. 2 were from the exact type of gloves. When a finger or hand gets pulled out, there is not much hope of getting it re-attached. Too much damage. I say one guy wearing that type of glove on a radial drill get his thumb pulled off. The leader that went up the arm came out with it, all winding up on the drill. however the lathe is by far the most dangerous machine in the machine shop, and it s my favorite.
What you do in your own shop is your own business. I have a bad scar on my middle finger from turning H-13. It was coming off like razor wire. I was turning the feed, and I felt the tool steel hit my finger on my right, so naturally I pulled back as fast as I could, and the razor sharp steel cut my finger open to the bone. If I had gloves on, I might have not cut myself as bad, or it may have wrapped up on the work and tore/cut my hand off.
I just wanted to pass on what I have experienced, not criticizing you at all. I think the smartest people are the ones that figure out a way to make what they need. You are that type of person.
Thanks for your time, and for posting.
Smiles,
Bill

Thank you for the compliment, and I highly appreciate your concern for my welfare, but I believe there's been a slight misunderstanding.


The video is an old one by Youtuber AVE, and not of myself. I believe it was posted to show there was an even simpler rotabroach design than the one I'm currently working on.

Be assured, no gloves are worn while I use my machines

[Metalmuncher]

I 've never seen a spring forced feed set up like you are describing but it might if there was sufficient spring pressure You would probably be about as well off trying to 2 hand one of the handles but what is really needed is an incremental direct feed system like mounting a worm wheel where the handles are and dog clutching it so you can use it when needed a simple hand wheel on the worm will do the trick
Also making worms and worm gears are not outside of the capacity for mini lathes or mini mills they just take a few homemade tools to be able to make them.one can always go the easy route and use all thread for the worm and a tap of the same size for the cutter to make the gear .

Aha! You know, the Fine Feed on most mini-mills IS a worm gear and knob setup. So perhaps the rotary broach WOULD work on a mini-mill, if advanced using the Fine Feed. I may yet give this a try. Especially since most of my projects are other than ferrous materials.

One thing I've learned in 15 years of working on mini-machines is that they have capabilities reaching far beyond what most people expect of them. It just takes determination, belief in the machine's potential, sometimes a few upgrade mods, and sometimes tossing the "books" and experimenting to find out how YOUR machine works, compared to how the old-timers tell you how it's done on professional machines.

[Canobi]

Got a bit further with my rota broach build.

I used a short length of mystery metal to make the tool holder out of as it was already very close to my target OD. I then simply drilled out the centre to 10mm:


After that was done, I thought I'd try my hand at a bit of tool grinding as my parting blade hasn't cut very well from the outset, despite having a very sharp edge. I'd seen some other types with a backward sloping relief on them so set out to copy it to see if it worked any better.

I didn't aim for any specific angle, just what felt/looked right and slowly went in till it reached the tip. It's a bit wonky, but not bad for a first go.


I then flipped the work round and put my newly ground blade to the parting test. All I can say is, I stood in awe and wonder as I watched my lathe take huge bites with ease during the parting job, so I'm well happy

It even left a nice finish on the work face, the stub came off with the excess so I simply broke the edge and used my tailstock to hold the 1/4" ball nose deburr I bought to make the recess for the bearing.


On hindsight, I think a ball nose endmill would have been better suited to the task as the deburr left a protruding nub in the centre which had to be removed. For that I used my boring bar with my toolpost turned to 45°. I then controlled both cross slide and carriage handwheels at the same time to nibble away at said dimple until it was either contiguous with the the shape of the recess, or dropped below it, as any raised area at the centre would prevent the ball bearing from mating properly with the recess wall.

Oddly I hit nostalgia central with that last job, man it sure brought back memories of playing with my Etch-a-Sketch


Next I carved in the off centre recess in the cup.


I chose the edge of the Jacob's chuck jaws as my stop mark for the cutting depth, loosened them and slid the deburr out a ways. I then carfully advanced the whole tailstock till the deburr touched the back of the cup. Then I0 set my calipers and advanced the tailstock quill till the gap from jaw to cup rim was equal to the required cutting depth and tightened everything down.


Interestingly, the deburr had a much more difficult time cutting the stainless than it did the mystery metal.

The boring bar was a no go for removing the nub this time as the cup was being held off centre in my 4 jaw chuck, so instead I used a drill bit, which worked just as well and didn't trigger any nostalgic side effects.

Not much left to do now...

[Metalmuncher]

Nice job!

Parting can be a pain sometimes. I have recently found that even on a fairly rigid setup, the type of material in the chuck presents different problems. I can part off 6061 aluminum, 1018 steel, brass, nylon, and acetal very nicely. But every time I try to do 12L14 "leaded steel" a.k.a. leadalloy, which normally machines very easily, the parting blade likes to go along nicely and then suddenly hog in without any warning. I've broken 2 of the blades (1/2 x 0.060 HSS) in this learning experience. Still haven't found a solution. So for now I bandsaw 12L14 off and face the end to dimension.

[Frank S]

you might try making one of these some say they work great I haven't made my own yet as I hardly ever do an parting anymore
http://www.homemadetools.net/forum/l...der-qctp-60469

[Frank S]

Also have you tried setting the parting tool just slightly above center

[olderdan]

Rear toolpost or spring tool holder is the only cure.

[kutzbill]

As an old timer, I have to say one of the best mills I ever seen is one that my friend made from a book he bought from "Lindsey's Books". He made the whole darn thing and I used it a couple of times to mill engine heads. It was a great machine.
As far as "Professional" machines, I started at a company on their CNC lathes, and I noticed their Bridgeport mill head was at an angle. I asked them when was the last time they indicated the head, and I got the deer in the headlights stare. It was .070 out of tram.
My boss bought a knee mill at an auction. It looked like the biggest wooly worm I ever seen. Apparently, the previous owner had put a huge magnetic chuck on it and the whole mill had a strong magnetic field on it.
Lind of sad that some really great machinist have to make do, and some others have the best, and use it as a drill press.
Smiles!

[Frank S]

Have the best an duse it as a drill press ha,ha, good one seen it done many times one guy actually thought the 3 HP Index mill with X Y&Z DRO was a drill press

[owen moore]

Years ago I worked for a company that had a sweet little Bridgeport J2. I used it everyday and I loved it. I left the company and went to work for another firm for 10 years. The original company wanted me to come back and when I did, I found out they had hired a couple of "pothead high school harry's" while I was gone. They had been using the mill table as an anvil when they wanted to beat on something. The table also looked like a large piece of Swiss cheese that had been attacked by termites. When I fired it up to use it, it didn't sound quite rite. I asked one of the two rocket scientists to give me the spindle oil can. He handed me a oiler can full of linseed oil! He said that is what they used in the past. I tell you guys- I was a half a pint away from taking hostages!