# Adding A Graduated Dial To A Compound Rest



## PAturner (Aug 29, 2016)

Hi, 
Hopefully nobody thinks I'm posting too many threads. Lots of questions are coming in quick succession as I explore my new (to me) lathe. 

The question I have today is can I add a graduated dial to the compound rest of a lathe? And by "add" I really mean add. There was never a dial included in the hand wheel system of the compound- only on the cross slide. Has anyone done this? Can it be done at all?




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## TakeDeadAim (Aug 29, 2016)

usually there is no space to put one if there is not one from the factory.  You could pull the handwheel and post a photo of the compound screw so we could see it.  A dial could be made but calibrating it may be a challenge.  What may be easier would be to add one of the digital scales to the compound and just read it that way.  The shorter scales are relatively inexpensive.  You could also use a long travel indicator to measure the travel when you need to.  a simple angle bracket could be attached to facilitate using the indicator.

You can not ask too many questions!


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## British Steel (Aug 29, 2016)

Start out by finding out the slide's feedscrew pitch! Use a dial indicator to measure how far it moves with e.g. 10 turns, divide to get how many thou" (or mm?)per turn - if it's something convenient there'll be other handwheel dials you can modify to fit (a lot have 50, 100, 200 graduated marks) by boring or sleeving  to fit the shaft you have.
Beware of the Chinese habit of fitting "something close", I've seen dials graduated 0-100 which actually moved the axis anywhere between 63 and 160 thou"...

Dave H. (the other one)


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## Bob Korves (Aug 29, 2016)

PAturner said:


> Hi,
> Hopefully nobody thinks I'm posting too many threads. Lots of questions are coming in quick succession as I explore my new (to me) lathe.    (snip)


You cannot get help unless you ask, and there are never too many ideas to choose from, only too few.  Mutual support is the purpose of this site.

BTW, I think your lathe is much closer to 100 years old than 50.  Please consider keeping it in as close to original condition as possible.  You have a piece of history there and they are not making any new ones...


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## chips&more (Aug 29, 2016)

Without a picture or two, you will not get a meaningful answer, sorry. But for a generic response. I tried to think back to when I used the graduations on the compound of my lathe. My answer is, I can’t remember the time, much less than a blue moon, that’s for sure. You could note the travel of the compound with one turn of the handle. Then approximate from there…Dave.


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## RJSakowski (Aug 29, 2016)

Years ago, I added a graduated dial to the tailstock feed on my Sears/Atlas 6 x 18.  The tailstock screw was 16 tpi so the dial has 62 full divisions and one half division for .001"/div.  The dial and index mark were made from aluminum.  It was many decades ago and I don't recall how I did the marking but given the odd number of divisions, I must have used the rotary table.  123 half divisions works out to 2º55'36" with a full division being 5º51'13".  

Since there is not a nice round number on the dial, I used it by figuring the travel distance in 1/16" increments with the remainder in thousandths.  For example, if I wanted to move .350", I would turn 5 full turns for 5/16" plus .037" for the remainder (.350-.313 =.037").

As mentioned above, Asian machines often use the approximation 1mm = .03937" =~ .040" to convert a metric lead screw to inch measure.  It can be annoying when trying to travel exact distances but for traverses of an inch or less that you would make with a compound, this error isn't too significant.  I use the practice of moving to the nominal position close to my final position, measuring, and making my final adjustment by the dial.  At that point, my error would bee a fraction of a thousandth.

How you actually make your dial will depend on your compound geometry  but based on the compounds that I have seen, you should be able to work something suitable out.  Here is a shot of my dial.


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## Jimsehr (Aug 29, 2016)

You could add a dial ,but why? It is not something you would use very often. And you could use an indicator if you need to check movement down the road. When I used to set up turret lathes I would count the turns on the turret stop and would come up within a few thousands of what I needed.
Jimsehr


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## RJSakowski (Aug 29, 2016)

I used the compound feed dial quite a bit before installing a DRO on my lathe.  

One example would be for cutting a shoulder a specified distance from and end face or another shoulder.  I would set the compound angle parallel to the ways and lock the carriage.  I then cut the first face  and advance the compound to the second face using the compound dial to indicate the distance. 

Another example would be cutting threads where the compound is advanced along the 29.5º angle.


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## Wreck™Wreck (Aug 29, 2016)

The shop where I work has a clapped out Warner & Swasey #5 turret lathe on which I do not trust the dials, when forced to use it for diameter work (it is 5" through the spindle so is the only machine that will take some parts) I use a cheap 2" travel dial indicator, works fine.

http://www.mscdirect.com/browse/tnp...CS_003=7867724&CS_010=80740806&mkwid=epmUISI5


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## TakeDeadAim (Aug 29, 2016)

The problem with dials on a compound is they are off the minute you put the compound at an angle as in to cut threads.


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## 12bolts (Aug 29, 2016)

Dials on compounds are pretty much standard on every lathe manufactured in the last 100 years.
They dont do this out of fun. A lot of machining of small parts can be undertaken with the carriage locked and the cross and top (compound) slides used for x & y travel. With the top slide set at 90* to the cross slide your graduated dials make it easy to know how much you are taking off. Also, you can set your compound at 6 degrees from parallel, your actual movement is 1 tenth of the indicated graduation, (give or take a tinsy bit) so you can be really precise in your y feed.

Cheers Phil


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## RJSakowski (Aug 30, 2016)

TakeDeadAim said:


> The problem with dials on a compound is they are off the minute you put the compound at an angle as in to cut threads.


That's where trigonometry comes to play.  You will have the same issue with a dial indicator.


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## Franko (Aug 30, 2016)

I use the dial on the compound of my PM 12-28 often. It is usually positioned in the X-Y axis and is much more controllable than the X-Y feed on the carriage.


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