Edgefinder Repair

[@ErikBongers]

Just want to thank you for this tutorial. Bought a Chinese edge finder and the surfaces didn't slide properly. They stuck at places. Had to even grind them on a 1000# diamond plate before honing them. The initial grind pattern showed a very uneven surface, with even a straight edge! Also deburred the inner and outer edges. Now they slide smoothly! Wouldn't have dared to touch the tool without this tutorial.

[@ErikBongers]

Half a year later, re-reading this comment, I realize I may have reduced the accuracy of the tool. If you imagine the extreme case where I ground the tool so far off that the lower part is at a 45 degree angle, it's clear that, while I'm still able to rotate around the spindle axis, the minimum rotation circle is no longer the diameter of the tip of the tool (4mm), but much wider! Not sure how to test this properly...

[@ErikBongers]

I know how to measure the error. If I touch off on both sides of a gauge block, the distance should be 1/2 the diameter of the edge finder's tip + the width of gauge block + 1/2 edge finder. In other words: subtract the gauge block size from the distance travelled and that should be 4mm, in my case!

[@ErikBongers]

Still. I'm not sure if it matters that much.... The sliding surfaces may cancel out any deviation. In which case the effective error is only determined by the contact area of the tip of the edge finder and the object. That is, if the tip of the edge finder is barely below the top of the object, there will be virtually no error. My apologies for abusing this comment section for my brainstorming.

[@ae.droidlivingroom9849]

Looking at the reassembly procedure where you tension and manually retain the tension spring, I would think that a thin piece of shim stock (0.1-0.3mm) inserted between 2 protruding windings would probably work as well to prevent the retraction of the tensioned spring while assembling.. This has the advantage of having both hands free to mount the spring cap. I think this would work well for fine pitch springs placed in a bore and are under little tension.

[@ErikBongers]

I agrxee compemetely. I juste reassemgeled onef and ifs painfuld. Sorrty for the bad typenig, my findgers are sore.

[@aserta]

The red small box (of shame) thanks you for showing that these can be fixed. Once my ruby stone shows up i'm going to give it a try, i want to do this on a new surface, the dings on mine are a bit deeper.

[@joell439]

I didn't know about how they worked either. I always thought they were magical :-). Thanks

[@cosimomarotta9552]

Another tip to record in my hobbyst knowledge. Thanks Stefan.

[@JTZshokunin]

Very cool! The .005mm error really surprised me... Maybe you can do a video about spring winding!

[@StefanGotteswinter]

JTZshokunin Those edgefinders are suprisingly accurate, 0.01mm is not a real problem with one of these - I did spring winding in apprenticeship, but I havent done it for a long time. Even if theres not to much into it. Just wind springsteel wire around a mandrel, preferable on the lathe :D

[@JaakkoF]

And bake them in the oven after winding so they relax and do net get an instant set when in use. If I recall correctly, 225 Celsius was the temperature or straw yellow.

[@JaakkoF]

The 0.005 mm can come from pretty much any source in this setup, like stick-slip in the machine ways, pitch error in the screws, backlash in the drive belts, bearings, round-off errors in the software, user induced errors, tool holder eccentricity, you name it. As for "what to expect" and "what you saw" the edge finder is good enough. Maybe Stefan can live with that ;)

[@Ujeb08]

It was good to see what's inside the edge finders. I never had the time to take one apart to look. Thanks for the video. What did you call that waxy grease you used as a lubricant? Jeff

[@StefanGotteswinter]

Ujeb08 Its vaseline or petroleum jelly, I dont know whats the common english name for it.

[@Ujeb08]

vaseline or petroleum are right in English also

[@felixar90]

I was half expecting to accidentally get the edge finder halves lapped and cleaned so perfectly that they wring to each other like gauge blocks.

[@ollyk22]

Can you do a video on the mechanical process at work with an edge finder please? I think it would be a first!

[@stavrious]

can t you do everything with the 6mm,what are the advantages of a bigger edge finder?

[@Jianju69]

Great tips and insights. Thanks for this!

[@jamiedominy2686]

Great stuff Stefan. Just looking at how these are made and came across this video.What was the name of the stone you used to lap the faces?

[@tedsmith3407]

hi Stefan my name is ted can you please tell me what size spring is in your edge finer ,as I wish to make a complete unit hope this fines you well and fit regards ted from south Africa. Ps enjoying your video's

[@jeffanderson1653]

Excellent

[@Terry8238]

Can you make them in the home workshop ?

[@StefanGotteswinter]

You can make anything given enough time :)

[@artmckay6704]

Thanks! :)

[@robertklein9190]

Nice presentation Stefan, but it's obvious that you've don't have a clue about baling wire, it's not so kind to animals too, twine used here.