A friend of mine just picked up an old Bridgport mill for parts and this was bolted to the table. We are both clueless as to what this tool is for, but I told him I bet I know a good place to find out!
It moves up and down and the knob on the back moves the stinger in and out. Any idea what its for?
My wild guess is that it is a tool for dressing a grinding wheel.
Looks like an adjustable tailstock to be used with, say for example, a dividing head. The 'stinger' is in fact ground to a 60 degree angle, and locates in a centre hole in shaft or whatever is being machined, providing support. Think tailstock on a lathe.
It looks like a dressing tool for a valve grinding machine. Pretty much like the one out in the shop for the Sioux grinder.
Brian has it correct.
Brian is right. I have one on my Bridgeport right now. I have the indexer on one end of a 32 inch shaft and the center supports the other end as I cut key ways in the shaft. Without it the shaft will move all over the place. Scott
The machinist who taught me more than a thing or two about working with a vertical mill told me that this device is properly called a "foot stock". As Brian points out, it serves a purpose similar to the tail stock of a lathe for holding a work piece between centers while cutting it to shape. However, when combined with a dividing head or indexer mounted on the bed of a milling machine, many more shapes other than cylindrical can be created.
Here is an example where I use a foot stock and a rapid index fixture on my mill. I have a 1908 Model S Roadster currently under restoration. One of the problems I encounter is that modern fasteners really do not look like the fasteners originally used on these cars. This is especially true where nuts are concerned. The standard nut used on these vehicles is for a 3/8x18 thread, but the size across the flats is 19/32, or about 15mm. 19/32 nuts are not commercially available today, at least not in the height and shape as the originals. So I have to make them myself.
Here is how I do it. First I have to carve a hex shaped bar in my mill. I begin with 3/4 inch round bar stock and set it up on the table of the mill as shown in the picture below:
On the left hand side the bar is held the rapid indexer, and on the right side is the foot stock. I like to use a rapid indexer rather than a dividing head because I can rotate the stock 1/6th of a turn more quickly than I can on the dividing head, and the indexer accepts 5C collets.
In the next photo, I am making the first cut on the work piece. Usually I can cut the first flat in two passes over the work piece.
In the third photo below the first cut has been completed, and I have rotated the work piece 60 degrees, and am not cutting the second of the 6 flats.
Once all six flats have been cut, I transfer the workpiece to my lathe. I have a 15mm 5C hex collet that I mount the work piece in. This is shown in the fourth photo.
Once the hex bar is in the lathe, I center drill the bar with the drill size appropriate for a 3/8x18 tap. Then I can cut the washer face on the bottom side, and, use the parting tool in the lathe to make the nut the proper height. Before making the full cut off, I will retract the parting tool and use a file to make a crown for the top side of the nut. This is shown in the last photo.
This finishes the operations necessary to create a nut blank. After this there are two more operations: tapping for the nut for the thread, and cutting the locking flap at the top of the nut. Lock washers were known in 1906-1908, and in fact there are two lock washers under the nuts for the crankshaft center main bearing bolts, but Ford used flaps on theses nuts instead. The flap is created by milling a 3/64th inch slot half way through the nut perpendicular to the bore of the nut 1/8th of an inch beneath the top of the nut.f Once the nut is installed and tight, the workman would hit the flap of the nut with a ball peen hammer to lock the nut to the threads of the bolt.
Really, this is the way they did it at the factory, and I make my nuts to the exact specifications shown on the ford factory part drawing. Of course, locking the nuts to the bolt this way pretty much makes them a one time use item, and I find very few original nuts when I disassemble an NRS car.
And this explains why one of the great features of a Model T I'd the use of castle nuts and cotter pins.
I'll go with Jerry and Scott on this one because I'm to lazy to go out to the shop to dig that dressing tool out. But it sure looks very similar.
Rotary table tailstock;
I'm sure this is not the original use, but it could be used for scribing a line on a rotating tire. First chalk would be rubbed on the center of the tire, then a line scribed by the above tool as the tire is rotated. The line would be used for setting the gather (toe in). I have seen something similar used in an alignment shop.
"I'm sure this is not the original use..."
Yes, it absolutely is. I've been around machine shops for over 30 years and have seen dozens of these in use.
Again: https://www.mscdirect.com/browse/tn/Indexer-Tailstocks-Accessories?searchterm=ad justable+tail+stock&navid=79641
Well there ya go. I worked in machine shops for 41 years and they were probably around and I probably used one a time or two but I don't remember. I even know a fella that just bought a lathe and a milling machine for his shop. He got a couple boxes of different attachments and tooling that I couldn't identify for him. And you'd think after 41 years I couldn't miss. But it just doesn't seem important anymore.
I do however recall using a tool very similar to the one shown to dress grinding wheels on a surface grinder. But I don't see the tip on this clear enough to tell if there is a diamond on it. And now seeing the sloppy way the end of the center is ground I've got a feeling someone better not give up their day job. At any rate I've got a feeling Jerry has nailed it down.
You misunderstood what I meant in my post. The tool was originally used on a lathe. The use I suggested was "not the original use" but another possible use for the tool!
No Norm, it was used for some special applications where you might need to mill a feature while set up on a vertical mill. But I like your idea too. It's actually very similar to a lot of tools used in a lot of different shops. But alas, at the risk of obsessing about it, we're going to have to give this one to Jerry. And that really gets under my skin because I thought for sure I finally had one right this time. I really did, but...
Very interesting Trent. Thank you.
Thanks guys for the info on this tool! My buddy will be glad to know what he has finally. Very interesting to see nuts being made as well.