Sunday, July 31, 2016

Bench Grider Tool Rest

Let's have a recap:
Since the demise of my terrible $3 Black & Decker bench grinder which didn't even have real bearings, there came a desperate need for a bench grinder that was actually good, the search began once again.

*I also had an oscillating sander by Black & Decker which also broke soon after I bought it at a garage sale. As a result, I've been living by the mantra: "Never Ever Black & Decker"
First checking in the local second hand machine tool shop finding this 70's Craftsman. $125 seemed like a bit much considering I had bought a welder for $25 and got a lathe for free. Still looks like a decent grinder nonetheless.
As it just so happened, the machine shop I was working at decided to change ownership and relocate operations to Ohio conveniently during my first year working there, which meant 50+ years of machinery was up for grabs at their auction! This of course included several bench grinders. Naturally, I wanted all of them, as well as all the Bridgeports, Hardinge/Mori Seiki Lathes, indexing heads, vises, the laser marking machine, etc., but due to monetary and space constraints, I had to settle for just one bench grinder. Let's take a look at the contenders:
Firstly, some unnamed one and a Jet.
There was this funny looking one with a table which turned out to be a tool & cutter grinder.
And another one. There were more, but I only took pictures of the ones I was really interested in.
I had accidentally bid $75 on a bigger one with a pathetic stamped sheet metal pedestal which looked like it would break if you sat on it, but fortunately, somebody else outbid me. I was eyeing this cute little one and ended up winning it for $25 with no competition! Now that I think of it, they probably didn't want to deal with the fact that this thing was completely covered with oil. It even came with a can full of oil, and apparently a free air hose!
Fast forward 2 years later.
The question must be asked, if my need for a bench grinder was soooooooooo desperate, then why didn't I build a tool rest for it right away so I could fully use it? Thus, this is easily the most overdue project in the history of Scrap Attack.

The only given attaching mechanism for a tool rest was a 3/4" hole drilled through the housing. Otherwise the only alternative would be to bolt it to the wheel guard which sounded less sturdy.
Since I didn't have any 3/4" threaded rod, I figured I'd just machine some bushings to fit into the 3/4" holes with holes for a 1/2" threaded rod instead.
The bushings and rod attached. Good thing I went with 1/2" as it gave me more room to attach the next bracket.
From this point, I didn't really have a plan, so I just started machining some brackets and eventually it worked. The first bracket: this one bolts onto the 1/2" thread and has a 5/16" slot to adjust the tool rest position. I began the slot by center drilling holes every .300".
Then using a 5/16" drill to do the actual holes.
Then an end mill to make the slot. Making the bracket out of aluminum made the cutting easier.
Then using my curvy tooth file to smooth out the slot.
Then for the next piece, some piece of steel that was already bent to the perfect shape I needed.
After cutting off the length I needed, using the same slot making method.
Except this time, the quill travel in my machine wasn't long enough to reach the slot, so I did the illegal machinist's maneuver of putting an end mill in the drill chuck, which actually worked in this case. I think that law only applies if you're side-cutting anyways.
Then filing the slot. The curvy tooth file worked better even though they say it's only for "soft" materials.
Conveniently, I had this 5/16" carriage bolt and locking mechanism from a microphone stand that I took apart, that way I won't need to get out a wrench every time I want to adjust the tool rest position!
Connected. But I figured I wasn't satisfied with the width of the rest, so I'd bolt on another piece.
The piece of scrap I used already had one 1/4"-20 tapped hole, so I just drilled another one, and then cut off the amount I needed.
Then facing off the ends to make it square so later I have the option to do some "Russian drill sharpening techniques".
Then drilling the corresponding bolt holes in the bent piece.
I was going to cut the 1/4" bolts to make them flush with the top of the rest, but then I figured I could just put some extra washers to make the lengths match up.
Oh yes, at last! No more excuses for not sharpening my high speed steel lathe bits! Now I just gotta get one of those green wheels for my carbides! The tool hoarding cycle never seems to end....

1 comment:

  1. I’d like to thank you for writing on this topic. The information you provided was very useful. I will visit again in the near future.

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