Recently, I brought home this 6" Morgan vise that Mitch restored for me:
One interesting thing about this old Morgan are the jaw screws. They're not standard! A search of common hardware suppliers turns up nothing like them.
Mitch and I discussed several options and on my last visit (when I picked up the vise) we were going to counterbore the hard jaws to accept button head screws. However, time got short and that didn't happen. I was looking at the vise today after working on hammers and decided I should finish it before I lose the one remaining original screw Mitch saved for me as a sample.
To begin, I measured the included angle of the screw head. Most common countersunk machine screws have a head included angle of 82 degrees or 100 degrees as shown below.
The head of the remaining jaw screw Mitch gave me has an included angle of 30 degrees, which I have never seen before outside of plow share bolts.
Looking at the jaw, I determined that the countersinks in the jaw are much to small in diameter to accommodate diameter "A" of the standard 82 degree or 100 degree countersunk screw as shown in the above illustration, negating any chance to use common hardware.
After a little bit of thinking, I found that the head of a common grade 2 bolt has sufficient material in it to make a copy of the original screw head. So, I began by making a slotting fixture to cut a screw slot into the head of a standard 5/16" bolt from scrap aluminum:
Then, I slotted a number of Gr. 2 5/16" bolts .070" deep, .070" wide:
Over on the lathe, I made a simple fixture to hold the slotted bolts so I could turn the head down to size:
Here's a photo I took as I was turning one of the heads down to the correct size and angle. This was simple plunge cut to diameter:
A few of the finished product, with a couple of extra bolts and the one remaining original screw:
The jaws installed with the new screws:
All in all, this took a little more time than modifying the jaws but it kept the vise mechanically 100% original. I made a few spares to lose in the toolbox somewhere, just in case.
One interesting thing about this old Morgan are the jaw screws. They're not standard! A search of common hardware suppliers turns up nothing like them.
Mitch and I discussed several options and on my last visit (when I picked up the vise) we were going to counterbore the hard jaws to accept button head screws. However, time got short and that didn't happen. I was looking at the vise today after working on hammers and decided I should finish it before I lose the one remaining original screw Mitch saved for me as a sample.
To begin, I measured the included angle of the screw head. Most common countersunk machine screws have a head included angle of 82 degrees or 100 degrees as shown below.
The head of the remaining jaw screw Mitch gave me has an included angle of 30 degrees, which I have never seen before outside of plow share bolts.
Looking at the jaw, I determined that the countersinks in the jaw are much to small in diameter to accommodate diameter "A" of the standard 82 degree or 100 degree countersunk screw as shown in the above illustration, negating any chance to use common hardware.
After a little bit of thinking, I found that the head of a common grade 2 bolt has sufficient material in it to make a copy of the original screw head. So, I began by making a slotting fixture to cut a screw slot into the head of a standard 5/16" bolt from scrap aluminum:
Then, I slotted a number of Gr. 2 5/16" bolts .070" deep, .070" wide:
Over on the lathe, I made a simple fixture to hold the slotted bolts so I could turn the head down to size:
Here's a photo I took as I was turning one of the heads down to the correct size and angle. This was simple plunge cut to diameter:
A few of the finished product, with a couple of extra bolts and the one remaining original screw:
The jaws installed with the new screws:
All in all, this took a little more time than modifying the jaws but it kept the vise mechanically 100% original. I made a few spares to lose in the toolbox somewhere, just in case.
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I gotta check my screws. I thought they looked rather similar when I had them out.
lol