I had my first major machine crash today

[Garwood]

Roger that I assume I need to check it twice, 90deg apart?

No, the actuator rotary union has super precision bearings inside it. If the spinny parts have any wiggle to them it will show on an indicator touching the housing.

 

[Milland]

No, the actuator rotary union has super precision bearings inside it. If the spinny parts have any wiggle to them it will show on an indicator touching the housing.

Those bearings may be dinged up from the stress, so check for noise or notchiness.

 

[William Lynn]

It can happen in a manual lathe too, but those typically don't spin as fast.

We had just gotten a couple of new manual lathes in the shop. One of the guys chucked up a long piece of skinny rod with about three feet hanging out the headstock bore. The new lathes had two ranges, with low range maxing out at 225 RPM. I don't remember what high range maxed out, but it was fast. He inadvertently had it in high range, probably at top speed. The rod bent and beat the snot out of the back panel. The scary thing was a salary walkway directly behind all the manual lathes. Luckily no one was walking past. Bad setup, but safety approved it. Guess they figured the headstock end of the lathe was a safe place to walk past.

 

[Bill D]

Thanks for the heads up. This weekend I will get around to chaining my vertical compressor to the wall so it can not fall onto me during a quake or if the drill press next to it spins something into it.
Bill D

 

[MrWhoopee]

Had it happen with an apprentice running a very old, small turret lathe. 5/8 od s/s tube projecting unsupported just a little more than spindle height. Two speed motor accidently switched to high speed. Broke the apprentice's finger (trying to stop it), broke the cast frame and walked the machine to the end of its cord.

 

[wood2steel]

It can happen in a manual lathe too, but those typically don't spin as fast.

Very True statement. These manual beast do command our respect as well. An Alarming occurrence no doubt, but most importantly, you were not hurt! Machine covers and our Pride can be patched up over time

 

[Scruffy887]

The blue pieces of sheet metal can be beat back into very good shape if you have a very stout and flat welding table. But never strike the sheet metal directly with a hammer. The small hammer marks will add little expansion stresses and make it look nasty. Always pound on a plate over the sheet. Helps a lot if you have a long piece of 1x3 steel bar and can clamp both ends over a section and wail away with a big dead blow hammer.

 

[Cole2534]

The blue pieces of sheet metal can be beat back into very good shape if you have a very stout and flat welding table. But never strike the sheet metal directly with a hammer. The small hammer marks will add little expansion stresses and make it look nasty. Always pound on a plate over the sheet. Helps a lot if you have a long piece of 1x3 steel bar and can clamp both ends over a section and wail away with a big dead blow hammer.

Thanks for the tips, I have all of those things.

 

[Cole2534]

No one at all has seemed concerned about the spindle itself. I'm guessing they're tougher than I imagined.

 

[Cole2534]

Pic of the outboard end of the drawtube. It is clearly borked.

 

[Garwood]

Pic of the outboard end of the drawtube. It is clearly borked.

That's not the draw tube. The draw tube ends at the chuck side of the actuator. That is the actuator.

I'd say that is completely fucked and unfixable. I'd be looking for a complete used actuator.

 

[Cole2534]

That's not the draw tube. The draw tube ends at the chuck side of the actuator. That is the actuator.

I'd say that is completely fucked and unfixable. I'd be looking for a complete used actuator.

I was afraid of that. I t still actuates, for now, without leaking but I don't know that I can trust it.

 

[Garwood]

I was afraid of that. I t still actuates, for now, without leaking but I don't know that I can trust it.

The potential problem is if the rotary union is dragging internally it will chew itself up and put metal in your hydraulics.

If it turns real easy, no dragging, it's probably OK to use it. If it feels like the rotary union is dragging inside you should do something other than just run it.

Thinking more- if it seems to run ok, you could just machine that end off. It's not really doing anything critical. Those bolt holes are to hold liners in. You can easily have custom liners made if needed.

 

[Cole2534]

Currently the TIR is reading 0.0025" at 60rpm with no noticeable increase in resistance when rolling it over by hand.

I'm going to attempt to realign it and see how I feel afterward.

 

[Overland]

I have a job coming up to machine ends on 1.25" hydraulic cylinder rods.
Don't have all the details yet, but the rod looks about 48" long.
My lathe has a 3.5" spindle bore, and the headstock is about 30" wide.
I figured I could make a simple bushing I could clamp onto the rod at the left end to support it in the spindle. I'd have maybe 15" unsupported sticking out.
Is there any kind of simple rule of thumb about how much unsupported stock out of the spindle is considered OK, please ?
Bob

 

[Cole2534]

I'll tell you 3 things I wish I'd done differently then and will do going forward

1) use a tight fitting bushing. Since youre talking rod stock 1.26" is where Id start for a bushing ID.

2) make the outboard bushing with a flange so it cannot slide into the spindle.

3) mind your RPM. My job was going great until it was time to part it off.

In your case, Id slide the whole rod in like you were going to work it and then gradually ramp up spindle RPM. See how fast you can go while still being comfortable.

 

[Tyrone Shoelaces]

You weren’t the first and you won’t be the last to have that occur. I’ve seen it happen three times. Last time it lifted the headstock end of a bolted down lathe about 2” or 3” off the ground. It all happened in a second or two. I had a grandstand view from the cab of the overhead crane.

Nobody got hurt, that’s the main thing.

Regards Tyrone

 

[Tyrone Shoelaces]

I have a job coming up to machine ends on 1.25" hydraulic cylinder rods.
Don't have all the details yet, but the rod looks about 48" long.
My lathe has a 3.5" spindle bore, and the headstock is about 30" wide.
I figured I could make a simple bushing I could clamp onto the rod at the left end to support it in the spindle. I'd have maybe 15" unsupported sticking out.
Is there any kind of simple rule of thumb about how much unsupported stock out of the spindle is considered OK, please ?
Bob

15” should be ok. Keep the speed in the “ sensible “ range. The last one I saw was roughly a 1 inch bar stuck out the back about 3 or 4 ft and the guy switched the lathe on without first checking what speed it was in. As it happens it had been left in the top speed range, over 2,000 rpm and the on/off switch was electronic, no clutch. So whoooosh.
The guy ran away and left it running and beating the concrete to death but luckily the fuses blew.

Regards Tyrone

 

[Fal Grunt]

Man, sorry to hear and see that! Poor little mazak...

Happy to hear it wasn't worse. I've never done bar work, but I've done plenty of loooooooong shafts back in the day.

 

[triumph406]

Had a friend working for me, was getting pretty good on a BP. I was out, and he decided he needed a 5/8 diameter spacer.

So he puts a 4' length of 5/8 PGP steel in a 5/8 collet, in my HLV-H, and decides to part off at maybe 1000rpm. I assumed he was thinking, "what could go wrong?"

By the time the spindle was upto 1000 rpm the 5/8 rod was bent 90 degs were it came out of the back of the spindle, the machine was rocking back and forward in his direction. Luckily he was able to stop it before he hurt himself.

By some miracle didn't trash the spindle or machine in general.

After that I locked out the lathes.