Best edge finder?

[Highpower]

(08-28-2012, 04:57 AM)Rickabilly Wrote: Another handy edge finder is the Laser one I have, it is pretty much a really fine laser pointer that has a shaft for spindle mounting and some centering screws for adjustment, you simply mount it in the spindle, turn it on, run the spindle, and bring it up to the edge, when you first see the light on the side of the work stop and zero the dials then continue travel until the spot is on top of the job and the lightest bit is still running down the side (just a shadow of the beam light, not that you can have a shadow of light, but you would know what I mean when you see it) read the dial, halve it and you have edge. They advertise it by saying just see the light and you're on centre and it's close but not quite, I prefer to split the beam. I have attached a picture below. It is really handy if you are setting up to parts that are complex in Z as you just leave the Z up to 12" away and the light beam does all of the "up and down work" for you, it's also great for centering drills in centre punch marks


Regards
Rick

I almost bought one of those until I saw the price.

Then one day I saw a sale ad ($20) for a similar unit designed for boresighting rifles. It had a much larger aperture and beam however for obvious reasons, but I thought I might be able to make it work.

I turned down an old brass pin punch to make a new aperture that would press fit into the units factory aperture. Then drilled a tiny hole through it so that only a pin hole sized beam can exit the laser. It works like a champ.

I mainly use it for lining up work in my drill press. As you say, it makes it simple to get a drill bit dead on a center punch mark with one try.
Also good for use in the lathe tailstock for offset drilling in a 4 jaw chuck.

[TOM REED]

HIGHPOWER excellent idea I will have to put that on my to do list, should br able to find boresight on e-bay cheap but one of these should alao be possible to make with a cheap lazer pointer, now the gears are turnun. tom

[Highpower]

(08-28-2012, 11:43 AM)TOM REED Wrote: now the gears are turnun. tom

Tom, that's good! Keep those gears lubricated.

Whatever you use just make sure you have a means of adjusting the position of the beam on your unit. I stuck mine in the mill spindle (fresh out of the box) and spun it by hand, and it traced out a nice little circle on the table.
Glad I didn't try to sight in any scopes with it...

The 4 set screws around the head allowed me to get it centered up when I was finished though. Spin it in the spindle now, and the dot doesn't move a bit.

[Mayhem]

(08-28-2012, 10:56 AM)Highpower Wrote: That is fine if you are working with rough stock, but what do you do if your work piece is already at it's final exterior size? ...

I figured that would be the answer but thought I would throw it out there. I expected the see someone throw up the use of cigarette paper!

[Rickabilly]

Well I was just about to in answer to snailmans question "are edge finders essential" well maybe not essential but handy. My advanced machining course did not mention edge finders at all and we were milling precision stuff. The standard method at that time was cigarette papers, simply bring a tool or precision ground bar up to the edge with the paper in between and stop when the paper "grabs" then take account of the tool diameter and you have found edge.

Rick

[SnailPowered]

Huh, sounds really cool. I think I could stand to use the cigarette paper method lol. I wonder if my little milling attachment has dials on it?

[TomG]

I used a 1/2" dowel pin as my "edge finder" for years. With a work light behind it, it was very easy to see when the rotating pin touched the side of the work. It worked every bit as good as the spring loaded edge finders but wasn't nearly as cool.

And while we are on the subject of edge finders, let's not forget the ultimate edge finder, the chair type.



You just stick them on the side of a steel workpiece (they are magnetic) or hold or clamp them against the side of a non-ferrous workpiece and indicate the slot or hole. Not nearly as handy as the others, but ultra precise. Moore makes one for use in their jig grinders (at over $4K on the Moore website, it's WAY too pricey for me, although I believe Bill Gruby has one). I have to settle for the knock off SPI version.

Tom

[rleete]

Highpower, that is a fantastic idea.

[Rickabilly]

(08-29-2012, 07:28 AM)TomG Wrote: And while we are on the subject of edge finders, let's not forget the ultimate edge finder, the chair type.



You just stick them on the side of a steel workpiece (they are magnetic) or hold or clamp them against the side of a non-ferrous workpiece and indicate the slot or hole. Not nearly as handy as the others, but ultra precise. Moore makes one for use in their jig grinders (at over $4K on the Moore website, it's WAY too pricey for me, although I believe Bill Gruby has one). I have to settle for the knock off SPI version.

Tom

It's not often that I see something I've not seen before in milling gadgets, but I've never seen the chair thingy, I suppose the best bit of it is that once you centre to it the spindle is right on zero so no need to offset.

I'm really liking this thread! new gadgets, yipee,
Are they really super accurate? as does seem prone to dirt or swarf getting under the register surfaces especially as a result of the magnets. not to mention being affected by dings or burrs on the edge maybe even a tapered side face. I fear it might appear accurate as you can set up with a DTI and so can fiddle till you have split the difference perfectly, but this doesn't account for the other little issues.

Maybe it's like digital verniers, they aren't more accurate than normal old school verniers, just easier to read and give a number that is recorded to 1/2 a thousandths of an inch when the frame is rarely accurate enough to take repeatable measurements within 2 thousandths of an inch, without special care(maybe just the right amount of care, but, I'm just trying to illustrate a point).

Maybe we should start a "Sister thread" or extend this one to include "centre finders" Another related topic where none of us could possibly have seen all the gadgets.

Actually I'm going to start that thread right now.

Best Regards
Rick

[TomG]

(08-29-2012, 11:54 AM)Rickabilly Wrote:

(08-29-2012, 07:28 AM)TomG Wrote: And while we are on the subject of edge finders, let's not forget the ultimate edge finder, the chair type.



You just stick them on the side of a steel workpiece (they are magnetic) or hold or clamp them against the side of a non-ferrous workpiece and indicate the slot or hole. Not nearly as handy as the others, but ultra precise. Moore makes one for use in their jig grinders (at over $4K on the Moore website, it's WAY too pricey for me, although I believe Bill Gruby has one). I have to settle for the knock off SPI version.

Tom

It's not often that I see something I've not seen before in milling gadgets, but I've never seen the chair thingy, I suppose the best bit of it is that once you centre to it the spindle is right on zero so no need to offset.

I'm really liking this thread! new gadgets, yipee,
Are they really super accurate? as does seem prone to dirt or swarf getting under the register surfaces especially as a result of the magnets. not to mention being affected by dings or burrs on the edge maybe even a tapered side face. I fear it might appear accurate as you can set up with a DTI and so can fiddle till you have split the difference perfectly, but this doesn't account for the other little issues.

Maybe it's like digital verniers, they aren't more accurate than normal old school verniers, just easier to read and give a number that is recorded to 1/2 a thousandths of an inch when the frame is rarely accurate enough to take repeatable measurements within 2 thousandths of an inch, without special care(maybe just the right amount of care, but, I'm just trying to illustrate a point).

Maybe we should start a "Sister thread" or extend this one to include "centre finders" Another related topic where none of us could possibly have seen all the gadgets.

Actually I'm going to start that thread right now.

Best Regards
Rick

Rick,

This type of edge finder is intended to be used on jig grinders where the parts are already hardened and ground, so burrs and out of square edges are not a concern. I was unable to find specs for it on the Moore web page, but I believe this edge finder is capable locating an edge within a couple of tenths.

I do have a chair edge finder made by SPI that use on occasion, but for general use they are definite overkill.

Tom