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View Full Version : Measuring distances on a Cincinatti lathe



Fasttrack
08-20-2007, 03:23 PM
Hey guys - one of the lathes in the student shop is a big WWII vintage cincinatti lathe. I don't remember the size for sure but it looks like it would swing 16" and its probably close to a four foot bed.

There are no dials on either the tailstock or the cariage hand wheel. We do have a 2" DTI but it needs to be setup perfectly parallel to the bed ways to measure accurately, correct? I made a clamp for the tailstock quill so i can indicate off of it but the holder for the DTI is a magnetic base. Its not very whoopy and tends to move around a bit.

Should i be thinking about making a holder that is more or less permanent on the lathe so it keeps the DTI rigid and parallel to the ways or ... ?

Thanks guys! This old cinci isn't used much for those reasons. THey have a harrison with a DRO (it only works in one axis... oh well) and dials and etc. Its much easier to use but i kinda like the old one... it looks like it needs some love too ;)

tattoomike68
08-20-2007, 03:51 PM
a DI bolted to a mighty mag is just fine. Eyeball strait is good for most stuff.

BadDog
08-20-2007, 04:05 PM
I made a simple holder from aluminum that clamps to the front v-way. Used what was basically scrap, only cost a small amount of time.

kap pullen
08-20-2007, 04:23 PM
Fastrack,

Old time practice was to layout the cut lengths with a majic marker, or chalk with tape measure, or scale.

Chalk a line on a cast iron part and you can mark that with a pencil.

Rough it out.

Finish the lengths using your micrometer stop, making measurements with a scale, or other standards such as a planer gauge, or adjustable parallels for precision lengths..

Some old time machinists made, had hardened, and ground, space blocks for this reason.

Someone still sells space blocks.

Mighty mags work ok, but can you remember how many revs of the dial you need every time?

One mentor of mine said he used a wooden length standard for a window prop at a new job. Got his rear chewed out after they looked all morning for that stick.

Least he didn't use that bit of string with the knots in it!

Kap

Fasttrack
08-20-2007, 10:55 PM
Hey thanks guys - now that you said something Baddog i remember seeing some of those holders here. Someone had a nice 3-D model of thier clamp... was that yours?

I may make one just for fun. I did the eyeball method today and it worked well.

Thanks for going over how its done Kap. Even if things have changed now with DRO's and etc i like knowing the way it used to be done... mostly because i know if i ever get my own full-size lathe it will be old and i wont have a DRO!

The dial indicator i was using was pretty cool - it had another dial inside that measured from 0-2" by .1 so it was really easy to read.

tattoomike68
08-20-2007, 11:06 PM
Its too bad its so hard to find a half way good travel dial, the kind with a wheel that runs on the ways.

One of us smart guys should fool around and make one and give the prints to everyone.

BadDog
08-20-2007, 11:58 PM
I'm pretty sure I just made it by the "seat of the pants". I've done some stuff in Solid Works for posting, but I don't recall ever doing one of those...

The first was made from scrap 1/2 plate aluminum. It had provisions for standard 3/8(?) DI collar and a SHCS to lock from the top. I then added a solid 1/8" rod that could be adjusted and locked in place. The only small issue was that if you let the saddle bump it under power feed, it could cock a bit and throw off measurements. But letting the saddle collide isn't good to start with and over all it was quite acceptable. This was for my Griz 9x20. The guy who bought it didn't have a mill (or skills/tools to make without) so I let it go with the lathe. Wouldn't fit the Rockwell without mods anyway.

The Rocky got one a bit different. For one, I used a piece of 1" thick aluminum scrap. For one thing, it's much more stable with less effort to tighten. But then, after some thought about how I tended to use it, I made another with no holes at all. With this one I set the location in whatever way is convenient, then I slide the block up to the screws on the way wiper covers and lock it in place. When the saddle gets close, I disengage the apron feed and finish the last 1/16" by hand (particularly if it's a fillet/form shoulder, bore bottom, etc.). I decided to do this because I found that over 90% of the time I used the rod instead of the DI. This lets me work totally from feel with no need to add "keep an eye on the DI" to the list of things I'm watching as I approach some critical feature by hand. But the bar itself can be problematic as things get hung on it (including my hand), it gets bent, and otherwise can be a PIA on it's own. The solid block is simple and has nothing to get in the way, and I find I use it almost exclusively except for the rare case that I actually NEED the DI for some reason.

Swarf&Sparks
08-21-2007, 08:41 AM
I remember someone posted on this site, a while back, re using digi-calipers as a poor man's DRO.

Maybe worth consideration, given the price of calipers now.

Fasttrack
08-21-2007, 12:12 PM
Yeah thats right ... i think Sir John may have have made one and posted some good info here. I'll have to check it out.

ckalley
08-22-2007, 05:43 PM
My Nardini lathe and the one in the shop at work have a graduated dial on the carriage hand wheel. I have found that it works pretty well to get you real close to final depth or length (+/- .010). Closer than that then you need to break out the depth mike or caliper.

Craig