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What type of grinding wheel is used on a Darex TR70 tap & reamer sharpener?

chippinchunks

Aluminum
Joined
Oct 11, 2016
Location
San Diego
Hello all

Can someone tell me what type of grinding wheel is used on a Darex TR-70 grinder? I purchased the grinder without a grinding wheel. I asked the seller & he said that it used a cone type grinding wheel. On my TR70 motor it says E-85,E-90,TR. Which tells me that the same Darex motor is used on the darex e90 & e85 endmill sharpeners too. I do have an E90 but the motor looks slightly different. My E90 also uses a cone type grinding wheel. I tried searching for pictures & information online for the TR70 but the few TR70 grinders that i saw were all using a standard round grinding wheel not a cone type. I downloaded a TR70 user manual here on PM & from the pictures in instructions it appears to be a round wheel too. Does any one know if the TR70 uses a round or a cone type grinding wheel? Any advice would be appreciated

Thank you
 

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I am assuming that model still uses a motor shaft arbor adapter that various grinding wheels are attached to. Once you come up with adapter, PM me sometime as I have a large collection of cone diamond wheels that you might be able to pick from (for cheap) that might fit that machine for carbide grinding. Also have a number of contacts that furnish abrasive wheels.
 
FWIW,
Mr. W. Noble posted several pics and a pdf manual as well on Vintage machinery website that shows a 3--screw clamp style shaft wheel arbor (with balancing capabilities). Looks like that machine will only have enough clearance for those straight wheels. Good Luck.
Johnny
 
I am assuming that model still uses a motor shaft arbor adapter that various grinding wheels are attached to. Once you come up with adapter, PM me sometime as I have a large collection of cone diamond wheels that you might be able to pick from (for cheap) that might fit that machine for carbide grinding. Also have a number of contacts that furnish abrasive wheels.

Any idea where i can get the motor shaft adapter for the grinding wheel?

Thanks
 
I have a TR-70 that I use. It does a great job on single flute or fluteless countersink bits. The wheel is a common 6 x 3/4 straight fine grit white aluminum oxide. I did not take the wheel off to see the wheel bore or the hub design. The hub may be the same one used on the E-90 to hold 1-1/4" bore flared cup wheels.

I made a stainless steel cover for the wheel guard because mine was missing when I bought it. My TR-70 has a 10-91 date code on the motor plate.

I think Darex discontinued the model years ago and probably no longer supplies parts but you could ask for drawings of the wheel hub. It should be a simple lathe project.

Larry

DSC02958.jpg DSC02959.jpg
 
I'm sure a straight bore arbor adapter with set screw would be available with a little Web searching; as a last resort, a flanged wheel arbor would simple to fabricate on lathe/mill!!
 
Micrometer measure of the wheel mount shaft might help in a search for a wheel mount adaptor.
length of the shaft and flat may also be an aid.

I agree it would be an easy lathe project, perhaps a Pm guy would make you one if having the dimensions.

Good to piggyback set screws on such a mount. (One set tight, and another tight on top of the first.)
Piggyback allows making tight enough and locked there with not distorting anything with overtightening.

The wheel fit might be made 1" or 1.250. The 1" to use with a 1 to 1 1/4 ring so to be able to use two size wheels.
 
Perhaps a dumb question, but did you try calling Darex? Even if they no longer make or support that machine, seems they'd know what wheel they used for it.
 
A word of caution about the TR-70. I know that some of these machines work on single flute countersinks. But the one I bought didn't. After much experimenting and head scratching I started beating on Darex for an answer. In January 2020 they wrote to me "The reason we discontinued it was a few reasons. 1. The volume was too low to keep it in our line, we designed it to grind taps and not many people wanted to regrind taps we found out... however they did buy it to re-sharpen countersinks and it was very limited in getting good results when sharpening countersinks. The through hole Weldon style it did great but for larger countersinks and especially single flute you could not achieve sufficient heel clearance on those. We altered cams and tighten up specs but as the sales for a tap sharpener did not take off we decided to stop production."

The only reason I bought it was to sharpen single flute countersinks. The insufficient heel clearance problem was what defeated me. The countersinks looked beautiful but would not cut. So I sold it and do not recommend the machine at all for any purpose.

metalmagpie
 
Perhaps a dumb question, but did you try calling Darex? Even if they no longer make or support that machine, seems they'd know what wheel they used for it.

I haven't called Darex but I did email cuttermaster. I sent them pics of the tr70 with the exposed mounted grinding wheel on vintage machinery & a pic of the motor shaft on my machine. Cuttermaster wrote me back & said they could help me out with a grinding wheel & possibly the adapter too. Ill keep yall posted.

Thanks
 
Update:

Brad from cuttermaster set me up with an adapter from cuttermaster that looks very similar to the original one. OD on the adapter is 1.25" so i can use the same cuttermaster CBN wheels that my Darex M5 uses. The new adapter works great. I did decide to use button head #10 cap screws like the original adapter to gain some clearance. Cuttermaster adapter part # CM-H1.25 (but with a .625" bore instead of .5") ordered it with cap.
 

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