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Thread: turning mandrels from rebar

  1. #1
    Join Date
    Dec 2003
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    washington.........STATE that is.
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    turning mandrels from rebar

    So I'm deeply engrossed in a BMG project, trying to make a series of accurate BMG's and the first thing that becomes apparent is that these things are BIG!!

    Not BIG! but BIG!!

    And I'm at the stage of making nice cases...... and I set out to turn some necks.

    I say "set out" because this project is a sidebar not a commitment. I ain't spending 170 on a bullet puller, 230 on a primer pocket swedger nor over $250.00 for a single-use neckturner just to make a point about accuracy.

    So off to the lathe.

    I keep sticks of 1/4", 3/8" and 1/2" 12L14 at the lather just for making sacrificial turning mandrels....... but half inch ain't big enough!

    P!$$ Poor Planning on my part. So I'm casting about for cheap easy-machining round scrap and I have literally tens of tons of rebar at the shop...... I jammed a hunk of 5/8 into the chuck, eyeballed it to center and whipped out a mandrel.....LIKE BUTTAHH!!

    Mighta' just found my new (free) mandrel material )

  2. #2
    Join Date
    Feb 2008
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    65
    I just use a grade 5 or grade 8 bolt ! I have lots of them around!

  3. #3
    Join Date
    Jul 2016
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    Surprise, AZ
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    It's the hotdog of steel...

    ...you never know what you'll get with rebar. It's made mostly from recycled material with little concern for alloy / etc. You might find a piece that turns well and another that defies a good finish. There might be some special purpose rebar that is more consistent, but I assume you'd know if you had such a thing. My luck with rebar was poor and I gave up on it as a general source of material outside of desperation. Bolts are more consistent - but an expensive way to go unless you have a bunch sitting on 'the pile'. I keep 12L14, 1018, 6061(al) and 4140 up to 1" for a very small investment (probably a bit more in the present economy). You're relatively near Onlinemetals which sells convenient 3' packs from 1/8" to 1" - probably get to you in a day.

    GsT

  4. #4
    Join Date
    Mar 2004
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    Montana
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    Best price on metal ?

    Is online metal the best/cheapest place on line, to purchase metal for lathe use ?

    Hal

  5. #5
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    Feb 2003
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    VA
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    I'll have to agree with GeneT, the rebar I have turned was the crap-y-est steel I've ever seen. Maybe in the NW they make it better.

  6. #6
    Join Date
    Jul 2016
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    Surprise, AZ
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    Quote Originally Posted by Hal View Post
    Is online metal the best/cheapest place on line, to purchase metal for lathe use ?

    Hal
    It's the best I've found between price and delivery time (delivery may suffer if you're on the East Coast, I don't think they have anything out that way). If you have a good steel supplier locally (good meaning "carries what you want") they're probably a better bet. My 'local' steel yard is great for welding steel and delivers for a $10 gas surcharge, but they don't really carry specialty alloys (like 12L14 or 4140). Speaking of which, IIRC, I had to go with (not-so-)SpeedyMetals for 4140. If you do order from Online metals and 3' lengths work for you they seem to be much cheaper to ship than longer stock.

    And if you find something better, I'm all ears!

    GsT

  7. #7
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    Jul 2005
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    Culpeper, VA
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    755
    Quote Originally Posted by Wayne Shaw View Post
    I'll have to agree with GeneT, the rebar I have turned was the crap-y-est steel I've ever seen. Maybe in the NW they make it better.
    The closer you get to Mexico the more varied the rebar becomes.

    A few years ago a radioactive source was melted into a batch of steel and used to make rebar.
    A radiation alarm went off when the truck pulled into a US lab facility, as opposed to leaving.

  8. #8
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    Feb 2003
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    Lower Dakota Territory
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    Why not simply use some .625 round 303 or 316? -Al

  9. #9
    Join Date
    Jan 2021
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    51
    Quote Originally Posted by brickeyee View Post
    The closer you get to Mexico the more varied the rebar becomes.

    A few years ago a radioactive source was melted into a batch of steel and used to make rebar.
    A radiation alarm went off when the truck pulled into a US lab facility, as opposed to leaving.
    I don't know that being close to Mexico was a factor because there is a lot of oil and gas drilling pipe that is radioactive. It is contaminated by naturally occurring radio active drilling product. Most scrap yards check and reject the pipe, but apparently not all. Some farmers and ranchers will use it for fencing.

  10. #10
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    Quote Originally Posted by brickeyee View Post
    The closer you get to Mexico the more varied the rebar becomes.

    A few years ago a radioactive source was melted into a batch of steel and used to make rebar.
    A radiation alarm went off when the truck pulled into a US lab facility, as opposed to leaving.
    McMinnville, OR has a hotdog, errr, rebar plant. It's output is made, I believe, entirely from recycled steel and unsuited to machining. I'm not sure proximity to Mexico is a good heuristic. If you were referring to my comment and my shown location I should note that my experience trying to machine rebar occurred when I was an Oregonian.

    GsT

  11. #11
    Join Date
    Dec 2003
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    washington.........STATE that is.
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    Quote Originally Posted by Al Nyhus View Post
    Why not simply use some .625 round 303 or 316? -Al
    I THOUGHT I had plendy round stock in the hamper..... but had nothing suitable.

    I live in the boonies an hour from town so the local 12L14 supplier is a 2.5-3.5hr round trip depending on traffic and gas is over a dollar.......and I wanted to go NOW

    I'd heard of folks making tools from 40-grade and read of the guy who made a competitive barrel from a hunk of #11 60gr so I figgered I'd spend a minute.

    I do have probably 10 brands and grades of rebar in the scrap, foreign and domestic and the first rusty staub I picked up just turned nice.

    Next pc may well be bubble gum but this piece turned like 12L14

  12. #12
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    Dec 2003
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    washington.........STATE that is.
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    Well.... I was wrong, I got lucky. The next two pieces machined terribly. I ended up making a mandrel from 1" stock

  13. #13
    Join Date
    Jun 2008
    Posts
    581
    Just buy a gage pin and press into a holder, hardened so they don't gall and sized to what you want... if you want you can even buy carbide...

  14. #14
    Join Date
    Feb 2003
    Location
    Tuff, TX
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    814
    Quote Originally Posted by GeneT View Post
    ...you never know what you'll get with rebar. It's made mostly from recycled material with little concern for alloy / etc. You might find a piece that turns well and another that defies a good finish. There might be some special purpose rebar that is more consistent, but I assume you'd know if you had such a thing. My luck with rebar was poor and I gave up on it as a general source of material outside of desperation. Bolts are more consistent - but an expensive way to go unless you have a bunch sitting on 'the pile'. I keep 12L14, 1018, 6061(al) and 4140 up to 1" for a very small investment (probably a bit more in the present economy). You're relatively near Onlinemetals which sells convenient 3' packs from 1/8" to 1" - probably get to you in a day.

    GsT
    Listen to Gene. In a steel mill, Heats of steel that miss their alloy specifications badly enough that they cannot be salvaged, end up as rebar, Fence wire, and nails.
    Joe

  15. #15
    Join Date
    Mar 2020
    Location
    Third Tomb of Chritianity
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    Quote Originally Posted by geo.ulrich View Post
    Just buy a gage pin and press into a holder, hardened so they don't gall and sized to what you want... if you want you can even buy carbide...

    What tool do you use to machine gage pin steel on a lathe ? Grinding add-on ??
    Thanks,
    Oliver.

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