Do-it-yourself Radius Dresser?

Any plans out there for a doityourself grinding wheel radius dresser?

Gunner, puttering with the KO Lee T&C grinder

I don't like to grind tap flutes with a rounded wheel edge because it quickly breaks down right along the cutting edge, unless the wheel is thinner than the width of the flute groove and cuts as it enters or leaves instead of tangentially. Then its shape doesn't really matter much, like a chain saw sharpener.

Actually a cylindrical Dremel stone slightly smaller than the groove diameter does a good job. I run the end of the stone down the groove to guide it and twist it slightly so it grinds the cutting edge of the flute. The stone cuts crosswise to the edge and wear doesn't leave a step.

This only roughs the edge to shape and doesn't control diameter exactly, but then you can grind the OD of the tap between centers with a spring finger against the newly ground flute groove. I got good results from a flat rather than circular relief. You can use the taper of the remaining thread grooves to estimate the relief behind the cutting edge.

Hope that's clear.

Jim Wilkins

----------- What sort of accuracy and sizes [wheel diameter and corner radii] are you looking for? I may be able to find locate some plans that use an inexpensive spindex for the spindle. The arm that holds the dresser has a stub that mounts in a 1 inch 5C collet in the spindex. No Schmidt,

it does pretty good. base spindex like this

Unka' George [George McDuffee]

------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).

Yep you mount a small straight shank boring head in the collet fixture with round shank diamond. Works almost as good as the schmidt.

Best Regards Tom.

> but it does pretty good.

------------ Fantastic suggestion.

Gunner is sure to have a boring head, and a 1 inch straight shank adapter is available from Enco fo 20$

Fabricate a holder with a 15% slant for the diamond dresser and be good to go. Use 1 inch sq steel (?) and turn a 1/2 diameter shank to fit the boring head.

Makes me want to run out to the shop and get started. Where's that 4 jaw chuck? If I only has a surface grinder...

I notice that the radius diamond dressers are 2X-3X as expensive as the phono point tools. Any difference for low volume use? Also see that the phono point dressers have 60, 70, and 90 degree points. Whats the difference for the home shop?

If you do this Gunner, be sure to let the group know how you make out, with pictures in the dropbox.

Unka' George [George McDuffee]

------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).

Actually...I really dont know what I need. Ive got some 40 or more grinding wheels of all types, some as thin as 3/16", and I figure I need a radius dresser to get between the flutes of shell mills, taps and so forth. I figure "close" is good, but Im not likely to be grinding maching grooves in things that need to be .00001

Just sharpening cutters of all sorts that have round gullets

Gunner

"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary that Roosevelt would be remembered as a great president, "maybe even alongside Washington and Lincoln," opining that Roosevelt "had every quality that morons esteem in their heroes.""

> but it does pretty good.

AH!!!! Excellent thinking outside of the box!!!!

Thank you!!!

Ill try that will a Yausu spin indexer Ive got.

Gunner

"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary that Roosevelt would be remembered as a great president, "maybe even alongside Washington and Lincoln," opining that Roosevelt "had every quality that morons esteem in their heroes.""

>> but it does pretty good.

Indeed I will!!

Gunner

"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary that Roosevelt would be remembered as a great president, "maybe even alongside Washington and Lincoln," opining that Roosevelt "had every quality that morons esteem in their heroes.""

The trick there is measuring and adjusting the offset accurately. I think you could make a setting block or assemble a gage block stack at center height and measure small radii for tap grooves with feeler gauges. I haven't tried that one yet because I can't remove the tapered adapter from my surface grinder and don't swap wheels unless absolutely necessary.

I did make a tailstock from a piece of 0.500 drill rod fitted into a steel block that bolts to an angle plate. I set it at center height by clamping the drill rod in a collet. It would make a fairly good height reference to set a radius dressing diamond with a ruler and magnifier to within 5 or 10 thousandths, about as close as you can determine the size of the groove in a tap.

Jim Wilkins

Echoing what someone else said, keep your eye on eBay. I picked up a Yuasa dresser there a while back, for less than $35 including shipping. The good thing about the dressers are that most of them are radius and angle dressers - you can do one or the other or a combination of the two.

John Martin