[photomankc]

Working on a project that requires a .750 bored hole in a block of steel. I have no boring setup for the mill and I wouldn't trust that to come out straight with my quill anyway. So I really need to use the lathe to do it. Problem is the hole is way off-center and so it puts the chuck greatly out of balance. To spin it up to 560 RPM was making the whole bench dance.

I tried this setup and it cuts the shaking down to a much more tolerable level but I can't totally eliminate it. I'm just not sure I trust this. Thought I would ask before I tried it. I'm not sure how well my carbide boring bar is going to handle this because there is no way I would want to turn this up to 720 or 1200 RPM.

I'm thinking about forgetting this and perhaps busting out the face-plate where I would have more leeway to balance it out better but I'm not real clear on using that yet.

[degreaser]

I assume that's a 4-jaw chuck. It looks like it.

Maybe you could mount a chunk of metal between the workpiece and one of the jaws so as to balance it out a bit.

[mwood3]

dont remeber where but i think ive seen something about mounting the the work piece on your cross slide and your cutter in the chuck...of course you would need to make a jig to hold the part at the right height/position...anyone else care to weigh in on this? a boring bar on a Mill would be a much better setup IMO. A boring bar is a good investment anyways...

[Arich0908]

Why not use a end mill to start and finish it with a reamer ?

[mwood3]

I have always been under the impression that a bored hole was more accurate thana reamed or drilled hole... I guess it comes down to your requirements...

[Flenser]

+1 on adding a piece of steel between the part and the short side of the chuck. I've done that a few times on the G0602 with good results (meaning nothing ever came loose and hit me in the head ; ). The clamps in the pic look dangerous.

[mwood3]

+1 on adding a piece of steel between the part and the short side of the chuck. I've done that a few times on the G0602 with good results (meaning nothing ever came loose and hit me in the head ; ). The clamps in the pic look dangerous.

I thought the same about the clamps but, I didnt know how the "steel spacer" would work either...most of my experience is on mills...

Its all about learning

[photomankc]

+1 on adding a piece of steel between the part and the short side of the chuck. I've done that a few times on the G0602 with good results (meaning nothing ever came loose and hit me in the head ; ). The clamps in the pic look dangerous.

I just don't have anything I can think of on hand with enough mass to be useful but small enough not to create clearance problems. I agree though, that little voice that made me want to check being present is enough to make me decide against it. After sleeping on it, the clamps are coming off. Gotta come up with something else.

[photomankc]

dont remeber where but i think ive seen something about mounting the the work piece on your cross slide and your cutter in the chuck...of course you would need to make a jig to hold the part at the right height/position...anyone else care to weigh in on this? a boring bar on a Mill would be a much better setup IMO. A boring bar is a good investment anyways...

I don't trust that wobbly quill to cut straight and it only travels 2". The part is 2.5" deep. The position of the hole is not critical but it needs to be very square to the sides of the block and 0.001-2 over the nominal .750" dimension. I'm not too sure I would care to take a swing at drilling a hole much over .625" in steel given my experience in order to use a reamer.

[mactec54]

photomankc

Turn the jaws around, The offset one is out to far, the clamps are fine, put a packer on the other side jaw to even it up a little, if that is not enough, add a piece of lead inside the clamps, then if you don't feel good about it, wrap duck tape around the clamps & part, start running slower than what you are running it, & take it up a hundred rpm at a time,you boring bar will work at any rpm even 50rpm so don't worry about trying to get the ideal rpm

[RomanLini]

I made up a surface plate with some threaded holes (that mounts to the chuck) for funky boring jobs. It can work well provided your job can be bolted to the flat surface of the surface plate, and you can bolt some weight (if needed) to the surface plate also to balance it out.

One of the benefits of doing it that way is you can balance the surface plate with job attached, before it ever goes on the lathe.

[knudsen]

boring bar will work at any rpm even 50rpm so don't worry about trying to get the ideal rpm

Yup, that's what beers for. Get's you through slow boring processes everyone must face in life.

When your lathe shakes, it's saying run it slower. When your mill shakes, it's saying run it faster.

[Flenser]

"When your lathe shakes, it's saying run it slower. When your mill shakes, it's saying run it faster. "

Where can I get a tee-shirt with that on it?? I already have one with your tag line : )

[knudsen]

If everyone had and wore your shirt, we might not be in the mess we're in!

[photomankc]

Ok, I dispensed with the clamps and found that my V-Blocks were just the right size to clamp against the sides with a perfect fit. Turned it on with that and I'm able to run at 560 with just a bit of vibration instead of the whole bench trying to walk around the floor.

tried to turn the jaws around but I couldn't get it to stay square when adjusted. One side wanted to lift up on me and after dialing it in 4 times and finding that the top was then .010" out of square I gave up and went back to the jaws facing in. Seemed to clamp down just fine and left about .3" of clearance above the bed. I'll try to figure out why that kept happening later.

I have the 5/8" starting hole drilled now and it went without a hitch. Went 1/8", 7/32", 5/16", 5/8" and all held in place. I would have been nervous as hell about the clamps but this I think was a lot safer route. Now I just need to finish the bore.

Thanks for the advise.

[mwood3]

that looks 100% better ...safer also

[Flenser]

If everyone had and wore your shirt, we might not be in the mess we're in!

Heh, it turned out to be quite the inappropriate travel garment. I was informed that wearing a Jefferson quoting tee shirt makes one a "high profile terrorist suspect" (actual TSA quote). Makes perfect sense to me...

[knudsen]

Ingenuity! Looks like a good, safe setup. What kind of lathe is it?

Heh, it turned out to be quite the inappropriate travel garment. I was informed that wearing a Jefferson quoting tee shirt makes one a "high profile terrorist suspect" (actual TSA quote). Makes perfect sense to me...

Wow! What kind of PC crock of $#|t has the great melting pot boiled down to? You're probably on the FEMA red list now. Where can I buy one for next time I fly?

[Flenser]

tee shirt The back to school marketing is pretty funny. I wonder how many schools would send a kid home for wearing that.

(sorry, thread hijacking over)

[photomankc]

Ingenuity! Looks like a good, safe setup. What kind of lathe is it?

Thanks, it's amazing what a night's sleep can solve.

Lathe is a Grizzly 10x22.