Tool Post Grinder ala Harbor Freight 44141 "ELECTRIC DIE GRINDER WITH LONG SHAFT" · Dec 2, 19:15
We had forgotten how difficult it was to turn RC60+ race-hardened ballscrews until we upgraded our X3 mill with standard, inexpensive Thomson rolled (standard grade) ballscrews and ball nuts.
Using the new inserts we had picked up from Hertel along with diamond-shaped inserts with a rather small radius, we began turning. Within minutes, the edge was gone. Resorting to the backup of the cheap triangle inserts, we turned away. It was just as difficult, but the edge held on a bit longer. And even when the edges dulled, it would still “cut”.
Taking way too long to turn down a bearing journal, we took out the DeWalt 4 1/2” angle grinder that’s commonly found around the garage, Home Depot, construction site. With the ballscrew held securely in a vise, we ground the raceways down until it barely showed.
Then we re-chucked it into the 12×36 lathe and used the insert tooling (and even ground HSS bits at this point) to get a decent finish without too much work (not to mention saving a few inserts along the way).
Then, we remembered that we could use a toolpost grinder on the 12x. Having seen the DuMores and the like ranging from $1000-$3000 (even used on eBay). That’s quite expensive…
So, on a recent trip to Harbor Freight, we picked up something we had wanted in the shop for years but never got around to buying… until now.
The Harbor Freight model 44141 long-reach die grinder with 25,000 RPM spindle and 1/4” collet, it maxes out at a 1 1/2” wheel diameter.
The main reason for purchasing this is that we thought given its long-reach, we wouldn’t need to make a motor/pulley/spindle setup. All that would be needed is a mounting block for the cross slide for which to mount a simple clamp for the grinder and we’d grind away.
Inside the box we get the grinder, two wrenches, and an instruction manual.
Here’s what it would look like mounted on the 12×36 G4003 lathe:
More on this project later. We already tested this theory by chucking in the rc60 ballscrew in the 12x and reversed spindle direction on the lathe at 1400 rpm (max of lathe) and used a cheap grinding stone on the hardened races. In under one minute, we had ground down the hardened crests the length of an inch or so.
This looks to be promising!
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