YABT (Yet ANOTHER ball turner)

[DICKEYBIRD]

All this ball-turner talk got me into gear to build another one. I had made a mount to clamp on a die-grinder for the QCTP a while back to use as TP grinder but chickened out and decided not to use it. (Abrasive damage worries.)

I couldn't let all that work go to waste so I used the parts to cobble up a ball-turner using a 2" R-8 shanked boring head. I didn't have any bronze to make the bushings with so I rooted around and found some plastic stuff I think is HDPE.

I turned 2 bushings, using the compound set over to match the R-8 taper for the front one.

The stuff actually works great and the clamp setup allows adjustment of the amount of friction.

I added a simple knurled disc & locknut for a height adjuster and turned a toolholder reamed to fit a 1/4" round HSS toolbit. I used the 1st ball it made on the handle of the tool that made it.

It clamps up nicely and is pretty rigid. The 10-32 bit grub screw is going to replaced by a setscrew to give more clearance when I can get one. Almost hit the chuck with it which would have been a disaster.

It makes nice balls so I'm happy with it.

The

 

[Lew Hartswick]

Did you rough out the ball before finishing with the "boring bar" turnner?
...lew...

 

[DICKEYBIRD]

No, I just started cutting with the the tool set high and went slow. After making the 1st sweep, I lowered the tool and made another sweep, then another until finished.

The ball seen in the pic was cut out of a 1.5" round and I did have to remove some stock from the back side with regular bits. Subsequent balls were made from blanks that were cut to the same length as the diameter and drilled/tapped/srewed onto a stud that was clamped in the chuck.

It's slow work but they come out nice.

Milton

 

[Bogstandard]

I have found that whenever I use my boring head for ball turning (very seldom), the only down side is that the adjusting screw is in the wrong place (underneath), but other than that it works beautifully.
I suppose the easy thing to do would be to grind a small slot in the other end of the adjusting screw with a dremel and cutting disc.

John

 

[DICKEYBIRD]

I fretted over that problem and came up with the same solution as you did John. I was going to slot the other end but decided to try setting the tool to the correct radius to begin with and make several cuts by just lowering it down from the top using the height adjustment of the QC holder. Seems to work fine that way. I had a heck of a time accurately measuring the radius but finally figured out a way to do it.

There's a website showing a boring head ball-turner and he went to the trouble of cutting new slots in the other end of the movable portion of the head so the adjuster could be reversed. That looked too tricky for me! :shock:

 

[wareagle]

Interesting method of mounting the collet. I had originally thought of utilizing the boring head that I have to build my radius cutter, but opted to start from scratch (had the materials on hand) figuring it would be a PITA to change back and forth. I must say I never thought of mounting it to the QCTP. I may look at that later and give it a go!

Hmmm.... Thinking about it a little further, I may look at getting another boring head and building a mount dedicated for the purpose.

DICKEYBIRD, that is a nice looking setup!

 

[Cedge]

Dickeybird...
I've been looking at your design and pondering a way to use my 3MT taper without having to cut an adaptor. I was over looking around on the LMS site when I stumbled onto a replacement spindle for the mill drill. Not much money and it will do exactly what I want it to do. Thanks for the inspiration.

Steve

 

[DICKEYBIRD]

Thanks fellows.

Steve, mightn't that 3MT taper tend to lock up as it was designed to when you get the end play in the assembly down to zero? Not sure, maybe moly grease or way oil would keep it from sticking. Or were you planning to use the spindle and the bearings and make a custom housing?

 

[Cedge]

Using the spindle housing with bearing surfaces seems the likely approach. The locking taper has been the buggaboo all along. Using the spindle would make the locking characteristic a plus. Since the spindle has no outer taper, it's a natural for use with bearings or even bushings. I do love it when idea storms strike me...LOL

Steve