Repairing Dynamic Tail Splits.
This is about fixing those Prentiss tail splits that everybody hates. I hope this is not too long of a post. I have a bunch of pic's since I was asked to show how I do it. I did not go to the books for heats and such but just went with a feel.
So anyway, I bought a Chas Parker #79. A big heavy 6-1/4 jaw width 180lb vise that had an issue with its split tail. It spread .060 where it was difficult to remove from the static jaw support.
<a href="https://visejaws.smugmug.com/Jaw-Cutting/i-sfTPrfC/A"><img src="https://photos.smugmug.com/Jaw-Cutting/i-sfTPrfC/0/S/Parker%2079%20%284%29-S.jpg" alt=""></a>
This is what the tail looks like after stripping the paint and cleaning the oil and grease.
<a href="https://visejaws.smugmug.com/Jaw-Cutting/i-rNn9jDQ/A"><img src="https://photos.smugmug.com/Jaw-Cutting/i-rNn9jDQ/0/S/Parker%20%2379-Dynamic%20Jaw%20Support%20%284%29-S.jpg" alt=""></a>
First I had to clean the split and after using lacquer thinner I used my torch to burn out the oil and grease. Brushed with an SS brush, heat top and underneath for a good 45 minutes till it quit smoking.
<a href="https://visejaws.smugmug.com/Jaw-Cutting/i-jtJPvbg/A"><img src="https://photos.smugmug.com/Jaw-Cutting/i-jtJPvbg/0/S/Parker%2079%20crack%20repair%20%282%29-S.jpg" alt=""></a>
Then I grooved the split with a carbide burr after drilling to stop that crack hole. The next step I took was to clamp it down on my milling machine and add two 5/16:18 Socket Head Cap Screws buried and plugged. I used the clamping to close the tail section close to 1/16 of split.
<a href="https://visejaws.smugmug.com/Jaw-Cutting/i-TswqMXm/A"><img src="https://photos.smugmug.com/Jaw-Cutting/i-TswqMXm/0/S/Tail-Split-1%20%286%29-S.jpg" alt=""></a>
Preheated the casting before TIG welding with my favorite cast rod Castolin Eutectic 224. I preheated till it got around 375-400F. I checked it only because of recording my heat, I actually went by feel, just kind of know when it is ready.
<a href="https://visejaws.smugmug.com/Jaw-Cutting/i-Ttvbq68/A"><img src="https://photos.smugmug.com/Jaw-Cutting/i-Ttvbq68/0/S/Parker%2079-finishing-1%20%287%29-S.jpg" alt=""></a>
Next I scrub the groove and start welding the groove. The tail section was beat on for decades and there was no way I was going to fill the whole area, so I just concentrated on the groove. I welded a root pass and cleaned and welded the final pass. Using a small peening hammer I peened the welded area to stress relieve the weld. Makes you look close to see if you missed a spot. Preheat again, wrap the weld up in heat pads and cool slowly. I use old leather gloves and heavy blankets.
<a href="https://visejaws.smugmug.com/Jaw-Cutting/i-ZDBR74m/A"><img src="https://photos.smugmug.com/Jaw-Cutting/i-ZDBR74m/0/S/Parker%2079-finishing-1%20%2813%29-S.jpg" alt=""></a>
It's not real pretty, but after cleaning it up it fit like a champ. I will use B.L.O. on this vise since it will hide some of the ugliness on the tail and eventually show off the finished vise mounted on custom stand in the Vise thread.
<a href="https://visejaws.smugmug.com/Jaw-Cutting/i-TTQPPMx/A"><img src="https://photos.smugmug.com/Jaw-Cutting/i-TTQPPMx/0/S/Parker%2079-finishing-1%20%2817%29-S.jpg" alt=""></a>
I know there are other ways to repair this type of split, but this is the way I felt comfortable doing it. Brass and arc welding are other methods you can use. The secret is the bolts in my method. Guys show your methods.