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Paul Alciatore
03-09-2005, 01:58 AM
This is a tip for those of us who don’t have DROs or CNC and who still use the dial readings when milling. I have no trouble reading the dials but counting turns on a long cut can be a challenge. There are always so many other things competing for your attention. Applying cutting fluid, clearing chips out of the way, wondering what that new sound was, etc. After I had to re start a 1.68” slot I was milling for the third time because I was unsure of the turns count, I decided that something was needed to help.

In about three minutes at the computer with my CAD program, I had a two inch paper scale that was divided into tenth inches and nicely numbered in the direction I was working. I also drew an index pointer right next to it. The accuracy need not be of the order of a caliper or even of a shop scale, but modern CAD programs and printers will produce a surprisingly accurate drawing when printed at a 1:1 scale. If the error is less than 1/40” at the full length, it is OK. If you are making a really long one, say 10” or more, I would check it against a good scale before use. In most CAD programs, you can adjust the print ratio to produce an accurate print on your printer. Notice that I used thick lines (0.007” wide) for easy reading.

http://img.photobucket.com/albums/v55/EPAIII/TwoInchScale.jpg

The two parts were cut out and slapped onto the table and cross slide of the mill with a few hobby magnets (I bought a pack of 50 at Wal-Mart for a couple of dollars and use them for many things around the shop).

http://img.photobucket.com/albums/v55/EPAIII/ScaleOnMill.jpg

The index arrow was set to the zero at the start of the cut and I made a small pencil mark on the scale between the 1.6 and 1.7 inch marks to indicate the end. Now all it takes is a quick glance at the scale to see how close to the end I am. No more forgetting the count. Actually, no more counting, period.

The picture was taken after nine parts were finished, two hours of milling, so it held up well. Using this technique, scales of any length can be made. Marks can be placed on them for any length cuts or at multiple hole locations. They could be used on other machines also; lathe or any machine that has slides and dials. Of course, you still have to read the dials for the exact locations but this eliminates the confusion and doubt of counting turns. Freedom!

Paul Alciatore

WJHartson
03-09-2005, 02:28 AM
Paul, neat idea, portable and cheap. Thanks for the idea.

Joe

egpace
03-09-2005, 02:35 AM
Paul,
Congrats! Beats my grease pencil and the old count... 2, 4, 6, 8, 10, etc.
Ed

Jim Luck
03-09-2005, 02:41 AM
Paul, this is why I use scales reading in tenths of an inch. Next, I use your idea all the time, just not as fancy. I use a fine-tip majic marker to mark my "0", then measure over and mark my stop point. This way if I get distracted, no problem. IDEA- you could clamp a 8 or 12" digital depth mic (or equiv.) on your machine and a lever to "catch" it. Using it would be easy and you can zero it to read either pushing or pulling the sliding rail/rod!.

Charlie Rose
03-09-2005, 03:12 AM
You can do this to the od on your lathe chucks/faceplates in degrees ,if done with care it is accurate enough for most jobs.

John Stevenson
03-09-2005, 04:20 AM
Paul, Neat idea but once you have determined the first long move just wondering why you don't use those sticky up metal bits to either side of the top magnets,
You know the bed stops.

John S.

Norman Atkinson
03-09-2005, 04:33 AM
Absolutely brilliant!!!

All that you have to do now is put another scale underneath and you have the cheapest vernier in history.

Gob smackin' in its simplicity

Congratulations

kap pullen
03-09-2005, 08:14 AM
That's a good idea.

Someone used to make these out of plastic
with a venier scale imbossed on.

You could hold -+ .oo1.

They had a self sticking back surface so you could mount them anywhere. And we did.

You stuck them on, then cut them with a razor blade across the joint.

kap

Michael Moore
03-09-2005, 10:37 AM
Paul, you might want to put your magnets in some thin plastic bags. It will make it a lot easier to remove all the sharp steel splinters that will be sticking to them.

cheers,
Michael

DBW
03-09-2005, 10:42 AM
I did the same thing to make a hand wheel scale for the down feed on my shaper. It took several tries to get the paper strip to match the circumferance of the dial diameter, but by using the CAD program scaling feature no problem. A couple coats of spray lac to protect the paper and it worked for me.
Don Warner
P.S. The same scaling feature would work for making the vernier scale.

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John Stevenson
03-09-2005, 11:02 AM
Paul,
Just re-read my original post, it sounds a bit like sour grapes, wasn't meant to. Good tip.

Don, I also did this on my old slotter, it had a 200 mark dial and it was about 1" in diameter.
Even Stevie Wonder couldn't read this on a good day.

John S.

spope14
03-09-2005, 11:05 AM
Good job, mind if I use the idea and make a few improvements to make it "student proof"?

Paul Alciatore
03-09-2005, 11:22 AM
John, No offense taken. This is just a BS session and we have to say what we think.

Others, I have thought of the vernier thing. I even designed a triple vernier scale for my drill press spindle feed: mm in 1/20s, inches in thousanths, and inches by 1/128ths (or was it 1/256ths). With some care, a graphics program and a good printer can be coaxed to the necessary accuracy. I never built it due to lack of time. But iot would be far, far better than the built in scale.

In this case, I think that it would be easier to read the lead screw dials. And more accurate than a homemade Vernier.

spope, Please, go ahead and try. But I doubt that anything can be made "student proof". Let us know of your results. And of the students interactions.

Thanks to all for the comments. I am happy to see it so well recieved.

Paul A.

topct
03-09-2005, 12:05 PM
A question about accuracy. Don't have a cad program but I do have Corel Draw. It shows measurments out to three digits. Is this true? Don't have a printer right now. But is some accuracy lost when sending it to the printer? Or does it matter what type of printer would be best, inkjet, laser? to attain that.

Used it to make a 2 foot diameter degree wheel for an artist friend. And it worked perfect, but for what they were doing being super accurate wasn't neccesary. Just curious.

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Gene

egpace
03-09-2005, 01:38 PM
<font face="Verdana, Arial" size="2">Originally posted by topct:
A question about accuracy. Don't have a cad program but I do have Corel Draw. It shows measurments out to three digits. Is this true? Don't have a printer right now. But is some accuracy lost when sending it to the printer? Or does it matter what type of printer would be best, inkjet, laser? to attain that.

Used it to make a 2 foot diameter degree wheel for an artist friend. And it worked perfect, but for what they were doing being super accurate wasn't neccesary. Just curious.

</font>

As long as the program is vector based, which I believe Corel Draw is, you should be ok.

Try a quick & dirty sample tick marked strip and check it with calipers before investing to much time.

Ed

Your Old Dog
03-09-2005, 03:59 PM
Question: In the same vain, would it work to Google a "How to read a vernier" web site, run the examples to printer, scale them to double size, (you could half the answer and improve resolution). Would that work too? I really like the idea. I'm a backyard guy and DRO's are a bit out of my league at the moment. Nice tip and I'll bet it gets a lot of folks thinking! My guess is we'll see more on this!

topct
03-09-2005, 04:37 PM
Your Old Dog, it might take a lot of trial and error to get it right.

The version of Corel Draw that I have is an OEM version. Something a computor maker could put in as one of those 'Software Included' type of deals. The real version of Corel is very expensive. This one cost about $60. It does do quite a bit of what the real version does but some of the features are either crippled or not there.

What's neat about is that you can for instance, measure the diameter of a machine dial, using pi you can get the exact circumfrance and basically type across the work area lines and numbers, 0 to 50 say, then all you need to do is punch in the circumfrence and bingo it will change whatever you have typed to that dimension. A vernier could also be made this way. Trying to figure that out myself.

Excuse my crude explanation. I am an amature at this kind of stuff. That's why I was wondering about the accuracy.

Maybe some one could suggest a cheap cad program that could also perform this function. Or some other solution?



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Gene

Iquithadenuff
03-09-2005, 06:38 PM
Why not just use a 12",18",or 24" scale in .100 graduations fastened to table, and even in "y"axis, with an adjustable witness fixed?

wierdscience
03-09-2005, 08:25 PM
Neat Idea!

egpace
03-09-2005, 08:56 PM
<font face="Verdana, Arial" size="2">Originally posted by Iquithadenuff:
Why not just use a 12",18",or 24" scale in .100 graduations fastened to table, and even in "y"axis, with an adjustable witness fixed?</font>

Back in the late 60's I ran an Index milling machine that had a vernier scale mounted on both X & Y axis. Took out any leadscrew error, but was a pain bending over and using a loupe to read it.
Ed

Paul Alciatore
03-09-2005, 09:53 PM
Re: Accuracy

I have had some experience with various drawing programs and printers. I like to use a drawing on self adhesive label stock for things like sheet metal work. I have a job comming up and I just got a pack of 17 x 22 label stock today. Cost $75 from a printer I use. It will save a lot of layout time. A LOT! It will pay for itself on this job alone.

Back to accuracy. My experience over a period of about 15 years is that vector based graphics programs, especially all CAD programs, are usually able to provide more accuracy than I need on any drawing of an object that will actually fit in my shop - or yours. This preserves internal accuracy.

Printers are another story. They vary widely and it's not just the printer but the driver software that Windows uses to operate them. Worse yet, you can get different error factors in the X and Y directions. A printer may be within 1/4% across the page and be off over 2% or 3% down the length. You can easily draw and print an XY scale that fills the page (7.5" x 10") and measure it with a good scale (one divided into hundreths is best). Measure the difference and calculate the percentage of error and then you can correct from there. I do this with every new printer I use and at intervals with the old ones. BTW, the type or cost of the printer is not a factor. I have seen very expensive lasers that were way off and cheap dot matrix types that were spot on. The resolution of the printer (DPI) is important as you can not get any finer than the smallest dot spacing you can print. An 8 or 9 pin dot matrix is almost worthless. A 24 pin is acceptable - barely. Lasers and ink jets are far better and they vary among different models.

The CAD program I use allows me to enter a scale factor at the time I print. I can enter numbers up to five decimal places so 1.00000 : 1.00015 would be a possible entry. So I can make fine adjustments but they are to both X and Y axies at once. Not the best approach. But I can choose one axis to have 100% accurate and live with the other. This is acceptable for printing scales.

Another trick is to print it 1:1 and take it to a good copy machine. Most modern copy machines will allow a size adjustment in 1% steps.

I have seen CAD programs and print drivers that did have separate calibration factors for the X and Y axies. Plotters frequently have this feature. Use them if you got em.

Like on the lathe and milling machine, accuracy is not totally automatic, it takes some thought, knowledge, and skill. But it is attainable.

Paul A.

egpace
03-09-2005, 10:37 PM
I agree with Paul, my earlier post recommended using a caliper to measure tick marks. Once I used Generic Cadd 6.1 to layout a 6 foot long stair stringer. I printed it out on my old 9 pin Epson wide carriage printer. When the printout finished, I found it to be nuts on over the 6 foot length! On the other hand, one laser printer I used at work on another project yielded a .070 over 6 inches. I do get great results with my B-size HP pen plotter. It's definitely going to depend on both your hardware and software.
Ed