Author Topic: Adding Vernier caliper to lathe saddle  (Read 3717 times)

Offline Brian Rupnow

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Adding Vernier caliper to lathe saddle
« on: May 26, 2015, 03:23:37 PM »
I have never been able to depend on the accuracy of the travel indicator dial on my lathe saddle. It always gets me close, but only close. If I build my "oscillating engine", I have to bore the cylinder to a very precise depth. The travel on my tailstock spindle is only 1 3/8" which is not enough. The cylinder will have to be bored with a boring tool held in the toolpost on my compound rest. For many years now I have thought about adding a Vernier caliper to my lathe to act as a poor man's DRO.----But----I didn't want to disassemble the cross slide to start drilling and tapping attachment points to it. This morning I studied on it for a while, and decided the tapped holes which hold the way-wipers would work for what I want to do, and still be able to hold the way wiper. So----First a hand sketch and some head scratching.

Offline Brian Rupnow

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Re: Adding Vernier caliper to lathe saddle
« Reply #1 on: May 26, 2015, 03:25:11 PM »
And then some quick modelling of the area in question to see if it seems reasonable.

Offline Brian Rupnow

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Re: Adding Vernier caliper to lathe saddle
« Reply #2 on: May 26, 2015, 03:25:52 PM »
Which quickly morphs into a drawing---

Offline Brian Rupnow

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Re: Adding Vernier caliper to lathe saddle
« Reply #3 on: May 26, 2015, 03:26:49 PM »
And then into a "to scale" printed off profile, glued to a cardboard backing and tried on for size to see if it is what I want--

Offline Brian Rupnow

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Re: Adding Vernier caliper to lathe saddle
« Reply #4 on: May 26, 2015, 05:19:20 PM »
So far, so good. That seems to hold the Vernier in a very stable manner. Now to figure out a mount for the other end.

Offline Heffalump

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Re: Adding Vernier caliper to lathe saddle
« Reply #5 on: May 26, 2015, 11:18:38 PM »
This is a really good idea Brian, we go though digital calipers at a rate of knots at work, unfortunately only 150mm travel ones, a bit too small for the Harrison.

Offline Brian Rupnow

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Re: Adding Vernier caliper to lathe saddle
« Reply #6 on: May 26, 2015, 11:50:17 PM »
Finished!! It works very well, I can reset it to zero at any point in it's 6" travel, I didn't have to drill any new holes in the lathe, and all it cost was $3 for a battery to revive the old Electronic Vernier caliper. I quit using electronic calipers a year ago and went back to a dial type mechanical Vernier because I like it better. It took me four years to realize that Verniers are good for marking out and rough measuring, but micrometers are for measuring anything that really matters. I modified my rear carriage stop to hold the other part of the Vernier. It takes me about 15 seconds to remove the caliper from the brackets or to re-install it. The Vernier will only be mounted for specific tasks, otherwise it will get all gunked up and not work.

Online mike mott

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Re: Adding Vernier caliper to lathe saddle
« Reply #7 on: May 27, 2015, 02:36:10 AM »
Nice one Brian, I have filed this away for future reference.

Mike
If you can imagine it you can build it

Offline mikemill

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Re: Adding Vernier caliper to lathe saddle
« Reply #8 on: May 27, 2015, 04:05:24 PM »
Brian

I added these scales to my Myford some time ago, the one on the cross slide had to go as was nigh imposable to keep clear of swarf, the one on the saddle works well like yours but you do need to watch the swarf, I tried a piece of clear Perspex as a shield but it got in the way. I also have one on the tailstock good for accurate depth drilling; they are a cheap alternative to a DRO system.
Cheers

Mike

Offline 1dbweldor

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Re: Adding Vernier caliper to lathe saddle
« Reply #9 on: June 21, 2015, 08:18:36 AM »
Well all I can say is I'M IMPRESSED. I thought I have seen it all. I stand corrected.