New edge finder - Now I have a family

[BCRider]

I do the lion's share of my milling with 3/8 and 1/2 inch shank cutters. And I use a 1/2" Starrett edge finder I treated myself to a few years ago a lot. But it always irked me that I had to change collets to find the edge readings then go back to the 3/8 to take the end mill I needed to use. A few days back I thought "I wish someone made a 3/8 edge finder... " And of course that had me scurry to the 'puter to check if that was a thing.... And it is! ! ! !

Imports were $26 from Accusize. But a full on Mitutoyo was only $32 ! ! ! HANG THE EXPENSE! ! ! !

So now I have an edge finder for either size.

[Paul Alciatore]

Interesting. It gives me an idea.

Edge finders work by the tip snapping when the center of THAT TIP passes the center of rotation of the spindle. The body and rear mounting stud of the edge finder do not need to have any particular relationship to that center of rotation or to the tip. The body just needs to have enough slop on all sides to allow the top to snap.

SO,

Why not just get an edge finder with a small rear mounting stud and then make one or more bushings to build that small small diameter up to the size of the collet in current use. A piece of drill rod or shaft stock will give you a start with a nice OD. Cut off a piece as long as the stud on the edge finder or a little bit longer. Put it in a collet in the lathe and drill/ream a center hole to match the edge finder stud. Then off to the mill to cut a single slit in it and you have your bushing.

An edge finder with a 1/4" stud would be perfect as you can bush it up to 5/16", 3/8", 7/16", 1/2", 5/8", etc., even 1" or more. Just pick the sizes that match the end mills you use.

You could even make an adapter with a smaller mounting stud with a longer piece of stock and a small stud on one end and a larger hole on the other to fit the edge finder. Slit the hole in three or four places and bend then inward enough to grip the edge finder firmly. But I wouldn't go too small with the stud end; perhaps 1/4" or 3/16" at the smallest. But even 1/8" may be OK if your edge finder is one of the electric types - with the light bulb that lights on contact.

The first idea of building the OD up with a bushing is almost certain to work. I am not so sure about the second idea about going down in the OD, but it is probably worth a try.

[luthor]

I use a Starrett 827 with a 3/8" shank, they also make a stepped adaptor (P/N PT28316) to suit 1/4 to 1.0 inch collets, which has saved me lots of collet changes.

[RSG]

Same here BCRider, constantly switching back and forth is a real pain. Like you my primary collets are 3/8" and 1/2" and so I have them in each size. The standard tip is .2" dia and in some cases I can't use them for finding an edge on a round part like the fishing reels I do because they don't extend enough to compensate for the quill to not run into the part so I have some with the .2" tip and some with the same shank dia. for the tip. They are an invaluable tool and I have tried many other things from wigglers to those gimmick LED gadgets but you can't go wrong with a simple edge finder.

[Dan Dubeau]

I worked with a toolmaker many years ago that made his own body for an edge finder with 3-4 steps in the shank for different diameters. Can't remember the details, and forgot about it until this post jarred the memory loose. Don't think I've ever seen a commercial version, but back in the heyday of manual machining, I'm sure somebody probably tried to make a go of it.

You've probably all seen the step shanked DTI stem holders before. Same concept, but with less steps and more precision.

[mklotz]

Making miniatures, I often have a 1/4" collet in place, so I bought a 1/4" shaft edge-finder from Fisher Machine Shop here in LA...

https://www.fishermachine.com/micro-edge-and-center-finders

As that page shows, they also make one with a 3/4" shank for the battleship builders.

Their products are very high quality.

[BCRider]

So it wasn't just me.... Lots of interesting tricks in the replies.

Paul, if I had started out with just the 3/8 size I might have thought of the same idea. But it's never too late to stea.... er.... "borrow"..... a good idea Coming up in the near future sleeves for the 5/8 and 3/4 collets. Nice idea!

Talking of needing special shapes or stepped bodies. Have you guys seen Joe Pie's video on making his own edge finder?

(3) Making an Edge Finder ---- On a Manual mill ??? - YouTube

And in my search with "making edge finder" to find Joe's video I also found a couple more.

(3) DIY Stainless Edge Finder - YouTube

And Tom Lipton did one too. But in his usual VERY complete manner it's in four parts. Here's part 1 and YT should supply the others in the suggestions list side bar.

(3) Precision Toolmaking Making an Edgefinder Part 1 - YouTube

Watching Joe's video I might just have a go at a 1/4" size edge finder as well. I've been buying a few of the smaller size end mills that have a 1/4" diameter shank lately as they are becoming more common and cost a couple of bucks less. So the need for a 1/4" edge finder to complete the whole "Goldilocks and the Three Bears Family" is growing. And I've already got the Papa and Momma finders... I'll just play some nice music, light a candle in the shop and leave a couple of thimbles of wine in the milling tool drawer and see what happens.

[psomero]

I've only ever had 3/8" EF's. I'm lazy so I usually leave the EF in the 3/8" collet in the spin rack so it's there for easy access.

If it's an amazon Mitutoyo, for that price it's probably an accusize with the name scratched off

[Doozer]

I've only ever had 3/8" EF's. I'm lazy so I usually leave the EF in the 3/8" collet in the spin rack so it's there for easy access.

Yup. Lives there for me on some of my mills too.

-D