Lathing Hex Stock

[JesseK]

I have a question to all of the machinists out there -- this is for the final production version of our shooter roller. As an fyi, there are springs on the inside of the noodles; hence we need a solid core to bolt the springs to.

The other day, we were able to bore out a 1/2" hole in our hex stock (1.5" face-to-face diameter, 6" length). We were also able to key it so it fits nicely on the motor shafts. I'd like to keep it as one solid piece though, so that the motor shafts stay perfectly lined up with each other. The next step is to lighten the durn thing, since the raw stock weighed roughly 2 lbs for 6". I know we could take it to the band saw and camfer the ends, but I was also wondering if we could lathe the middle down at all? In the picture above you can see that the middle part of the aluminum roller hex is lathed down a bit -- is this possible?

I don't mind the weight overall; I believe we'll be under budget with what we're trying to do. However, this particular piece will sit about 36" off the floor, so I feel I at least need to investigate this. We stand to lose about 1/2 a pound if we can take away the material in the middle.

Thanks in advance!

[MrForbes]

I don't see why not. All it takes is a lathe, a qualified operator, and some time and energy.

We made a shaft for a small transmission for a FP motor by using 3/8" alumnium hex stock, and turning the ends down to 3/8" round to fit into bearings. We were able to get it concentric enough just using the 3 jaw chuck to hold the hex.

[JesseK]

Gah, I didn't quite pose the question correctly. I should say that I'm worried that each edge of the hex will break the cutting tool as the hex spins around. The edges of the hex are further from the center than the faces, so it wouldn't be a smooth cut at first. Also, our 'qualified operator' recently had a baby boy and hasn't been able to participate this season. I'm the next best thing since he taught me some of what he knows, yet I want to be careful.

When lathing down the ends, you at least have a face to mill into using ... whatever that angled pointed cutting bit is called.

[MrForbes]

As long as you don't take a huge cut, it will be fine. As I said, we machined hex shaft without any trouble at all. I didn't mention the hub for our feeder roller, it's made of 1" aluminum hex that we faced and bored in the lathe, no problems.

[Justin Stiltner]

Shouldn't be a problem to do that, just take it light while you still have the interrupted cut. If you have an inexperienced / excited person running the lathe have them use HSS (High Speed Steel) tooling instead of the insert style, HSS is very forgiving of abuse. Also using the tail stock to support the far end will help with the vibrations, not to mention keep bad things from happening.

[MrForbes]

Another thing, you don't really need to cut a full rectangular notch in the part, you can leave a big radius at each end of the cut...this is easier to do, and will make it a bit stronger.

[Borisdamole]

Originally Posted by Justin Stiltner

Shouldn't be a problem to do that, just take it light while you still have the interrupted cut. If you have an inexperienced / excited person running the lathe have them use HSS (High Speed Steel) tooling instead of the insert style, HSS is very forgiving of abuse. Also using the tail stock to support the far end will help with the vibrations, not to mention keep bad things from happening.

you can still turn down hex stock with carbide, but HSS is cheaper, and it still works.

Interrupted cuts can be slightly frightening at first, but as long as you take light cuts, and make sure everything is clamped down tight, you should be fine!!!