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Tap grinding

reggie_obe

Diamond
Joined
Jul 11, 2004
Location
Reddington, N.J., U.S.A.
In a pinch, easy to regrind the end of a plug tap into a workable bottoming tap by hand, but not so easy to turn a bottoming tap in a plug or taper type. What would the proper fixturing be to grind the taper and clearance on the flutes? Would this require a T&C grinder or would a universal cylindrical grinder be a workable compromise? Recommentdations please.
 
Tap grinders

Well, there are dedicated tap grinders.

if you have a tool room grinder there is always the Axial / Radial releiving fixtures by Weldon, RUSH, and etc.

IF you don't and you have a budget then the TDR/SRD family of drill grinders will do taps.
 
Darex used to make a fixture for sharpening taps and countersinks. I don't know if they still do or not. It consists of a 5C collet spindle equipped with user selectable cams to permit from 1 to 6 tooth per revolution of the hand crank. It works okay.
 
Weldon Fixture

Probably more of a fixture than you need, but I have a Weldon "Model S" relieving fixture, with a large selection of cams and collets for sale for $500 plus shipping. This fixture can be used for drills, c/sinks and taps and has a fine feed adjustment that lends it self to being used with a surface grinder.

CM
 
Model Number

Probably more of a fixture than you need, but I have a Weldon "Model S" relieving fixture, with a large selection of cams and collets for sale for $500 plus shipping. This fixture can be used for drills, c/sinks and taps and has a fine feed adjustment that lends it self to being used with a surface grinder.

CM

What is the model number of the fixture? It looks very interesting. I tried to look at Weldon's catalogue and did not see it.

Denis
 
What is the model number of the fixture? It looks very interesting. I tried to look at Weldon's catalogue and did not see it.

Denis

No model number as such marked on the unit. Just "Model S" on the tag. This unit is a bit different then the one listed in the catalog, as it can be set up for axial or radial relieving (relief on the end or on the diameter). Also,this unit uses 180-DA collets, rather than the 1-1/4 bushings the other fixture requires.
 
Taps are cheap and available. Is there a reason you want to do this?
Tom

Plethora of new bottoming taps, USA brands available at sub $1 prices. My current needs for bottoming taps is well supplied, so I thought I'd explore the process to regrind some of them into taper or plug style. Same sort of reasoning with owning a fixture to re-sharpen zero and single flute countersinks (still on the wish list).
However, while the fixture looks like just the ticket, the $500 exceeds the cost/benefit analysis.
 
I've got a Reading tap grinder attachment that I'll be selling soon along with a bunch of other stuff. Look for an ad in the Tooling FS section here if you are interested in it.

Mike
 
We have a very nice little grinder setup that sharpens twist drills, reamers, taps, etc. It has a small six jaw chuck with a handle that causes the chuck to rotate as well as its base to swivel back and forth. It has a series of cams which you would change for the proper number of flutes. The base swivel can be locked out so that it does not rock and roll but just rotate the chuck and move in and out.

It's a great little machine I wish I remember the brand, we have it in "storage" for the next few weeks.
 
Does anybody have any info on the Reading Tap Grinding Attachment, Model B. there seems to be a bit of a vacuum on the hinternet regarding these units.

Thanks

Walter
 

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I think I have tap grinder like in post 13.. and will put it up for sale if I ever get back in town long enough..

Quick fix tap sharpening is to spin a circle grind to the angel and number of threads you wish. Yes just spin it to the wheel.
Next roll it up to make a 7* clearance and and grind to just make the land go away to become sharp edged.
neat grind away the heal(below the cutting edge to a small land if the 7*.

Quick fix if needing the same tap is to grind the flute face (top) on the lead in angle part..The OD stays the same and is very often still sharp enough..

[cylindrical grinder be a workable compromise?] that could work very well for spinning the lead circle grind.. but for the clearance you would add a finger or indexing device.. I could use a lathe dog on a CG to make a stop and bring each flute to just sharp.
 








 
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