Q.C.T.P. Indicator Holder

[DICKEYBIRD]

'Nudder project finished...and in a less than a weekend even!

I was trying to tackle aligning the headstock and tailstock on my little lathe using the "Rollie's Dad's method" mentioned elsewhere. Early attempts at measuring runout using a magnetic D.T.I. stand were frustrating and inconsistent so I decided to make a dedicated holder for my Q.C.T.P. I keep forgetting to buy a dovetail cutter so I made this holder from separate pieces using the tilting angle table to cut the 60 deg. angles. This is the 1st really useful job i've done with Mr. Ishimura's table design and it worked great!

I used some aluminum I had lying around since it won't see heavy pressure and a piece of shafting liberated from an inkjet printer for the gauge mount shaft. I made it long enough to reach bigger chunks I may need to dial in later. The clamp block is 1/2" CRS drilled & reamed to fit

I'm not really happy with the clamp knob...I hate having to fumble around with a wrench to adjust it but a big enough knob to give sufficient clamping would hit the chuck jaws when using it on short parts. At least it gave me a reason to use the spindexer to make the tube nut. Only lost focus once and mis-cut a flat.

[nheng]

Nice job! Who makes the angle plate that you're using? Den

[PTSideshow]

very nice,its always a good feeling when it comes together like you know it would with out a lot of rework.

[DICKEYBIRD]

Thanks guys. I built the angle table based on Mr. Ishimura's plan on his great website. He's an inspiration to me.

http://homepage3.nifty.com/homeshop-tools/tilting_angle_table/tilting_angle_table-e.htm

[cybor462]

I'm not really happy with the clamp knob...I hate having to fumble around with a wrench to adjust it but a big enough knob to give sufficient clamping would hit the chuck jaws when using it on short parts. At least it gave me a reason to use the spindexer to make the tube nut. Only lost focus once and mis-cut a flat.

Just a thought, could you have made the end of the nut as a thumbscrew style? That way you would have plenty to grab and tighten and it could be the same size as your nut head so it would clear the jaws. Just a thought.

Your holder is very nice. Your work is very precise. I would not have tried a dovetail with out a dovetail cutter. Nicely done.

[DICKEYBIRD]

Thanks Cybor. I actually made a thumbscrew larger than the nut with a knurled rim but couldn't get enough torque on it to lock it down. A much bigger one would do tighten up well but would hit the jaws on small jobs.

[Tin Falcon]

Dickeybird:
Nice work looks like a handy tool.
It is interesting the different aproaches to the same project in this case a dovetail. Just goes to show you do not need a special cutter or a shaper to make one.
Tin

[BobWarfield]

Nicely done!

This approach to dovetails may make them easier for a lot of folks to do.

Best,

BW

[BadDog]

I love your table, now I just gotta find a cheap piece of t-slot table...

I also made a QCTP mount for my indicators, but I'm lazy and didn't go to that much trouble. I just took a piece of 1/4 strap scrap, about 3/8" wide and 4" long, cleaned it up, then tapped it 1/4-20. I had a cheap POS magnetic mount with short ball knuckled arm only about 4" long (just like the normal cheap magnetic mount arms, only shorter). The magnet was so pathetic it would stay in one place at all, so it's now in the junk bin, er, sorry, "parts bin". Anyway, that short articulated arm mounts on the strip of scrap, which is usually mounted on the back side of that near useless knurling tool holder that came with my PII tool post. Very handy, and easily removed if I want to mount a cutter in the holder, or put the arm somewhere else.

I have one suggestion for you clamping/holding dilemma. Why not use what is sometimes called a "split cotter" design? It locks much more securely with less pressure on the thumb screw, so a small brass head would be fine. It's similar to the way tools lock into a turret head, which is a non-split cotter I guess.

[DICKEYBIRD]

Thanks B/D. My table is piece of a H/F Micro-Mill (X-1) I got it a few yrs. ago from Little Machine Shop. Seems like it was only $25-30.00 at the time. Mr. Ishimura made his own t-slot cutter and slotted a chunk of Dura-Bar to make his. I ain't quite there yet!

Is a "split cotter" like your basic dial indicator holder gizmo where one piece fits inside another and the shaft passes through a hole in both? If not, could you post an example?

[BadDog]

Not exactly, and I don't know where to find a pic, so I'll try to describe.

Imagine a vertical hole to hold your vertical bar. Then drill and bore a hole horizontal that protrudes about 1/4 diameter into the vertical hole. Now make a pin to fit that horizontal hole with a smooth slip fit, drill the pin through and tap on one end. Lock it in place somehow such that the top of the pin is just above the surface of the block, and the threaded end is at the bottom. Now drill/bore through the cross pin so you take a bite out of the side and the vertical bar will slide smoothly through. Remove the cross pin and cut straight through the narrowest portion. Drill non threaded portions of cross pin with clearance drill for thread selected. Now put a thumb screw to hold the 2 pieces of cross pin (the "split" cotter) together and insert into block. Line up "bite" and insert vertical rod. Light thumb screw pressure will lock it securely.

[DICKEYBIRD]

OK, like the drawbar that holds r/c model engine carbs on some brands. Thanks!

[cybor462]

Dickeybird... I did not write what I meant. I meant a winged thumbscrew. I just call them thumbscrews but I am wrong.

[DICKEYBIRD]

So, what was the 1st thing I needed to use my brand-new indicator holder on? Yup, piece of square stock in a 4-jaw which needed way more travel than the little D.T.I. could measure.

A couple more clamp blocks and a spacer to fit a 1" travel D.I. and the job was easy! It's looking pretty cobbled up now but it's very rigid and works.