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-   -   Edge/Center Finders (https://www.shopfloortalk.com/forums/showthread.php?t=50255)

milomilo 12-04-2018 09:33 PM

Edge/Center Finders
 
Looking at edge/center finders for the new to me mill. There a different styles. I know nothing about them as to which type is best.

Thinking about getting one like this. Comments?????

Ironman 12-04-2018 10:09 PM

I got a set of those, but often use a thin piece of paper instead.
Something I find far more useful is a co-axial indicator
Pay no attention to ra-ra American made blah blah accuracy nonsense. These things are not for accuracy, they are for centering, and as they rotate you move the cross slides to find the spot where there is the least wiggle of the needle. You don't measure with them.
They are useful on a mill and held in a tailstock chuck are useful in a lathe as well.

digr 12-04-2018 10:14 PM

I use masking tape, close enough for me.

cutter 12-04-2018 10:38 PM

Quote:

Originally Posted by Ironman (Post 725918)
I got a set of those, but often use a thin piece of paper instead.

Quote:

Originally Posted by digr (Post 725920)
I use masking tape, close enough for me.

If you want to be fancy about it you can spend your money on Starrett precision paper or Brown & Sharpe machinist tape.
Stay away from imports like Mitutoyo. Rice paper shreds into dangerous slivers bamboo is too stringy.

milomilo 12-04-2018 10:41 PM

Quote:

Originally Posted by digr (Post 725920)
I use masking tape, close enough for me.

Do you mean instead of a thin piece of paper?

milomilo 12-04-2018 10:50 PM

Are we all done?

digr 12-04-2018 10:58 PM

I use the tape it sticks to the part

GWIZ 12-04-2018 11:43 PM

Yes, single end, 3/8" shank, 0.200 tip is what I use all the time.

https://www.shopfloortalk.com/forums...40&postcount=4

Double ended ones do not hold very well in drill chucks so I don't recommend them, (shanks are ground just a little smaller so the chuck clamps on the larger diameter of the tip) .

Rob65 12-04-2018 11:58 PM

Chris, for finding punch marks and lines etc I use a pin.

A trick taught to me when an apprentice is put a piece of plasticine, blu tak , chewing gum or whatever on the cutter and stick a taylor’s pin to it. Run the mill at a couple of hundred rpm and true the end of the pin up by pushing it with the back of your thumb nail. Don’t worry about the head of the pin, it’s only the tip that needs to run true.

Once its running true you can use a jewellers eye glass (loop) to line it up with marks. It’s plenty accurate enough for most things quite easy to get within a few thou like this with the right eye glass.

Not sure the health and safety nazi’s would like this in a work place now but this was in the early 1980,s and I still have all my fingers For working at home it’s your risk.

To me it’s easy, quick, accurate & cheep, what’s not to like?

As others have said, use a piece of paper to find edges.

Different papers have different thickness but if you are working to any accuracy you will have callipers or a mic to hand so easy to measure if that degree of accuracy is really necessary.

For me the most important accessory to have for a mill is a sharpie marker pen. Use it for marking out, then scribe lines through it (like dyechem),put a mark on the work piece and touch down until the cutter scratches it to pickup surfaces and also without a DRO use it to mark the dials so you can keep track of where you are relative to the reference faces of the work piece.

Expensive high tech is all well and good but for hobby use the old tricks are usually plenty accurate enough in skilled hands, which I’m sure yours will become with a little practice.

Enjoy your new toy.

Rob


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LKeithR 12-05-2018 12:15 AM

Quote:

Originally Posted by GWIZ (Post 725927)
Yes, single end, 3/8" shank, 0.200 tip is what I use all the time.

Double ended ones do not hold very well in drill chucks so I don't recommend them, (shanks are ground just a little smaller so the chuck clamps on the larger diameter of the tip) .

I prefer single ended style but in 1/2" diam., not with the reduced tip diam. The larger diam. seems to wait just a second longer before popping and therefore I think I get a slightly more precise location. Very rarely do I have need of anything else. And if you're using an edgefinder be aware that you can't run them too fast--I usually limit mine to 700-800 rpm. If you go faster the centrifugal force of the tip when it's offset will overcome the strength of the spring that holds it and in an instant the tip is going whackety, whackety, whackety against the vise or the workpiece and it's instant scrap. You'll try to avoid it and most of the time you'll remember to check the speed before powering up the spindle but if you use an edgefinder much you will eventually waste one. I know because I several in a drawer in my toolbox.

As for papers just grab a pack of cigarette paper. They average between .001" to .0015" in thickness which is plenty close enough for most of what I do. If I'm starting from scratch I'll usually use an edgefinder but I occasionally run into a situation where I've already got a tool in the spindle and I need to find an edge--it's real simple to grab a cigarette paper and run the tool up against it--drill, endmill, counter bore; it doesn't matter. I usually turn the speed up a bit; seems to make for a little more precise location.

A co-ax indicator is a great tool but it's no good for finding edges. It is, however, the slickest thing ever for finding the centre of a bore or locating the centre of any round feature on a part. I wouldn't be without one...


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