Quick and Easy way to Edge Find?

jlsmithseven

Registered
Registered
Joined
Jan 16, 2017
Messages
216
It seems that I spend too much time edge finding. Whenever I have a piece in the mill that needs cut on 3-4 sides, I have to edge find each side once I take it out of the vise jaw. My friend recommended edge finding on a corner of the vise jaw and just using that as a zero and lining up the piece with the square. This seems fine, but our vise jaws are very inaccurate and I don't feel it will give me the precision I need. Is there any other method that will make it easy for me to just put a piece in and have the same corner as my 0,0? Thank you!
 
Well, the "hard jaw" (fixed jaw) should repeat well enough for that axis. For the -X- axis, you could simply put a dowel pin in a collet and move the table in that axis until it is at your zero position, offesetting 1/2 the diameter of the pin, and bump the work up against the pin.

If the work is not critical, I sometimes just stick a magnet to the end of the jaw and use it as a temporary stop. Of course, you could build or buy a stop for the -X- axis and set up to use it. If your -Y- axis doesn't repeat, I would work on the vise until it did. It should, adequately for most work. Even a good vise has a little give to it that will cause variations in the work position using a standard vise handle and human strength.
 
If you doubt that the machine being used including work holding will do what you desire then no there isn't a better way. If you know beforehand where the inaccuracies lie program or move accordingly.

If precision is of the utmost concern find the corner of each part as you describe, slow but accurate, this time will be included in the quote that the Customer receives.

When you leave school and begin working the people quoting the work will take this into account if they are skilled. If not there will be a good deal of animosity on the floor.
 
Last edited:
The hard jaw of your vise should be rigid enough to offer a consistent zero plane from which to reference your workpiece location. If not, there is something wrong with the vise, vise setup, or you are not tightening it consistently from part to part. Once this is sorted out, your Y-axis should be considered taken care of. Any number of stops can be employed to establish zero on the X-axis. I typically use one of the small parallel clamps that straddles the hard jaw and locks into place by tightening a socket head cap screw. Once affixed, it takes some serious, localized force to move. The more robust stops that clamp to the table T-slots are good options, as well. The Z-axis is most usually controlled by use of the vise's base rails, a set of parallels, or some play on the 1-2-3 block, depending upon the size of your part. I've also used multiple grinding vises clamped in the mill vise after being accurately set up on the surface plate, which works really well if you have several matched grinding vises and a skilled operator setting them up for you as you do the machining.

Another consideration is asking what level of precision are you trying to achieve? A setup reaching for a +/-.010" tolerance can be approached much differently than one requiring +/-.0005", of course. I enjoy striving for a tolerance of zero in my work. The number on the print is what I intend to hit but in the manufacturing environment, this is neither reasonable, cost effective, nor long tolerated. Think of the print tolerance as defining the scope of your setup, and do just a bit more than the minimum to achieve this goal.

When doing high-precision work on the mill, there are two methods I use pretty regularly. One involves the small jaw clamp mentioned above and my Indicol ( https://www.anytimesale.com/INDICOL-178-UNIVERSAL-INDICATOR-HOLDER-p/204590.htm ) to sweep each part an verify zero. This arrangement easily locates parts to within .0005" with a bit of care and patience. Using the jaw stop gets my next part located very close to where it needs to be and saves a lot of sweeping and futzing around with table movement. It goes pretty quick once you get the hang of it and provides plenty of accuracy for most applications. This ideally used when your part zero is off the centerline of your part, as is usually the case when working in a mold shop or similar environment.

The other option is similar to the above but will precisely locate your CORNER zero. The Indicol holder is again used, but I swap out the jaw stop for one of the table mounted versions and set the stop pin down low on the part so it's out of the way of what's about to happen up near the top. Using a device I've always heard referred to as a "toolmaker's chair" as shown here: http://www.swissprec.com/cgi/ISSRIT2?pmaka=98-337-9&pmctlg=01� Mine is slightly different and there are several different styles, but you can see what's going on with this one. These are precision ground and locate to the edge of your workpiece using very strong magnets. With this model, sweeping the hole at top will give you a true corner zero with minimal fuss. Again, it goes pretty quick once you get the hang of it.
 
Back
Top