2016 POTD Thread Archive

Making 8 tapped tubing end plugs for one of my camera rigs. I could never be a production machinist...making multiples drive me nuts

+.001 with locktite

I'm with you on that, Toolmaster. I hate doing multiples. I had to build 20 drawers when I made my kitchen cabinets. It was torture. Especially varnishing them — three coats on twenty drawers.

wood i can do all day.

I learned about boring bars in my shop recently. On my bike stand adapter, I had to bore out some 1.5" tubing to make it fit two different size components. The only thing like a boring bar I had were the ones that are supplied with a mill boring head, with brazed carbide inserts. They work ok in the boring head but never very well on my lathe.

I dug in my stuff and found an indexable boring bar I had purchased years ago after I got my first lathe. It was a 3/8" indeaable bar and wasn't up to the task, chattering and squealing and producing a horrible finish on the inside of the tubes.

I checked the boring bar tool holder that came with my AXA toolpost and saw that it would hold a 5/8 tool. So, I ordered one from Shars. It got here today and I tried it out on a piece of scrap tube tonight and the difference is night and day. I can now bore large smooth holes.

Then I discovered that my boring tool holder will also accommodate a 3/4" bar, so I ordered one of them, too.

Not having much experience with boring bars, I have a question. It seems like if I set the carbide cutting edge at the center, that it would drag. The CCMT insert is pretty thick. I mounted it a tad higher and got very good results. Is that generally true with indexable boring bars? I was boring a 1.25" ID tube. Maybe on a larger diameter it would be ok on center?

Lood said:

Yesterday, we serviced my old truck and discovered that the sump plug had basically been destroyed. Needless to say, no one knew who removed it during the previous service, so I decided to make a new one, using a piece from a 42mm scrap pump axle. I also got to use my recently purchased indexing head for the first time:


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I like it but feel that you should have left it as round bar so that at the next service they can get a better grip on it with their monkey wrench .

Funny you guys should mention multiples. This is what I was doing this afternoon. Seems the professional machinist missed a change and made some parts (end caps) with the wrong ID. Luckily my Atlas/Craftsman 12" lathe came to the rescue and turned down the 38 bushings to fit. Got a little boring but it was nice to see all the shiny parts when done. These parts are for a product we are manufacturing that is used on tiller steering outboard motors to dampen and reduce steering torque.

i could use one of those on my horizontal bandsaw..

Round in circles said:

I like it but feel that you should have left it as round bar so that at the next service they can get a better grip on it with their monkey wrench .

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Believe me they actually did use a monkey wrench on the original. It was supposed to be removed with a large allen key, but they probably couldn't find the correct one. I actually considered machining the new one for an allen key as well, but I think this is better.

TOOLMASTER said:

I could never be a production machinist...making multiples drive me nuts




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That's why I became a toolmaker instead of just a machinist. Once I even got let go from a place because I refused to work production for a couple days. They wanted me back after about a month. I told em I would only come back if I never had to run production. Went back as foreman of the shop and then went into engineering designing special machinery.

Depending on the parts being run, multiples can be a good time for reflection on all that is good and right in the world of machining.

Drilling cross holes in screws for safety wire, with a box of 1,000...perhaps not so much.