Turning bar stock and steady rests

We have a cnc lathe, Hurco TM6i. A job is coming up making 400 some odd pins of various lengths out of 1.0" 4340. We are going to buy 12' sticks and the average pin is 4" long. We have not had such a quantity of parts before so we haven't had a need to hold material that long. How do you use the steady to hold the material safely outside the machine while turning while using a bar puller to advance the stock? Is there some other way I'm not thinking of to do it?

There aren't many things more dangerous in a machine shop that a bar whipping around on the wrong side of the headstock. Jerry-rigged supports don't cut it.

I cut 12 footers in 4 pieces, and use the right size spindle liner. That keeps everything contained.

I think you should definitely not try to Rube Goldberg some thingy to try to hold 12' of 1" steel barstock . If this thing comes loose, you can do tremendous damage and/or injury + death to anyone in the vicinity. Also you would need several of them, so you don't have a couple feet of bar swinging free.

Cut the bars to whatever length will fit fully inside your spindle and put a few inches long sleeve on the end of each cut piece, OD a bit under your spindle bore and ID 1.01" or so, with a couple setscrews to hold it in place.

I use a pneumatic pusher. The end of the pusher has a 45* concave cone cut into it so the bar stays centered. Bar and pusher are fully contained within the spindle.

Regards.

Mike

Used Machinery & Industrial Equipment | HGR Industrial Surplus

Looks like lot's to choose from.

I've got a bar loader on my little Sharp. Works pretty good as bar feeders go- I've never seen one that wasn't a little bit fussy.

You load up the magazine and it just cycles until it runs out of material.

Cut parts to slightly over double length, machine one end then the other, saw or part to length. If the part has a lot of steps this may not work well. In that case do as others have said and keep the bar short and centered.

Ed.

Definitely cut the stock shorter. You are taking a real big chance by trying to jerry rig something. If you don't want to buy a bar feeder, look into a bar puller. Royal makes a great puller that is activated by coolant pressure. Sounds kind of hokey, but everyone in our shop loves them.

CNC Lathe Whipping Barstock - YouTube
Watch this and you will see how people and machines can be killed.

Unless you are going to be running this job over and over I would have the parts sawed to length you need at a saw shop. It will save messing with a cut off tool in the lathe. And having a bunch of bar end waste .I had bar tubes for most of my lathes but found it guicker many times to have stock sawed.
Jim

redlee said:

CNC Lathe Whipping Barstock - YouTube
Watch this and you will see how people and machines can killed.

Click to expand...

Moron, .......if anyone in that shop couldn't see that was asking for trouble, they shouldn't have been there in the first place.

Limy Sami said:

Moron, .......if anyone in that shop couldn't see that was asking for trouble, they shouldn't have been there in the first place.

Click to expand...

That was a 3" round bar BTW . Guy probably figured there was no way a 3" bar would move like that. Probably also had CSS enabled by the looks of it, so all was fine and dandy at the entry, then it wasn't.

Regards.

Mike

Finegrain said:

That was a 3" round bar BTW . Guy probably figured there was no way a 3" bar would move like that. Probably also had CSS enabled by the looks of it, so all was fine and dandy at the entry, then it wasn't.

Regards.

Mike

Click to expand...

That's how I read it Mike ....did you see how the machine was moving around on a ''centre point''

Another example:

http://www.lni.wa.gov/Safety/Research/FACE/Files/LatheStruckByBar.pdf

What's scary about this one is the owner didn't learn the lesson even after a man was killed. He "corrected" the problem with the most half-assed support you've ever seen. See the pics.

redlee said:

cnc lathe whipping barstock - youtube
watch this and you will see how people and machines can killed.

Click to expand...

hey, whats that noise?

For certain work, it is wasteful to cut to 4 footers, so there is some incentive to go longer.

You wouldn't have to do a half-ass job of jerry rigging something. Go full-ass and build a nice frame attached to a heavy plate on the floor. Build up the equivalent to a lathe bed and build a bunch of steadies to go on it. Or build the equivalent to a long spindle tube on this mount and put spindle liners inside to guide the stock.

I did this on a very small scale for turning 1/4" diameter rods starting with 12 footers. Basically, I used a heavy angle iron and built some trucks attached to that angle with bearings to guide the shaft, so nothing was coming out of there. I also used an inverted live center cone on my bar pusher (gravity fed weight) on the far end so there was never a moment when the shaft end was spinning in free air (as might be expected of using a series of steadies). I used a heavy pillar as the support for the angle. Considering the low mass of this part turning at 2000 rpm (max for that machine), the main concern is to be able to damp any harmonics arising from the shaft flex. It doesn't go deadly in a single turn, it takes lots of input cycles to build the high energy. If you keep sapping that off, the shaft is ok.