One of the most common questions people have about vintage vises is how old they are and the answer is often mostly a guess. Most manufacturers didn’t use date stamping on their vises, so there are only a few clues for us to work with. One clue can be changes to the design/style of the vise that took place at a known time, allowing people to say their vise is either before, or after, a ballpark date. The other common clue can be patent date markings since issue dates are easily determined in most cases.
Luckily, when you’re trying to determine the age on a Wilton vise, it’s usually pretty easy. Unfortunately, a lot of bad information has been published on the topic but I think enough good information has finally been collected that things are more clear now.
For those who don’t already know, the slide key on most Wilton vises has a date stamped on it to indicate the date the vise was ready for release (sale). The slide key is a square length of key stock that fits into a groove in the body of the vise to keep the front jaw from rotating. Unscrew the slide all the way out, flip it over, and you’ll probably find a date stamp in one of several formats. Some will look like 9-945, which would be September of 1945. Some will look like 9-50 which would be September of 1950. Others will look like 6-30-60, which would be June 30, 1960. Others will look like 12-31-60 and have “GUAR EXP” above the dates indicating the manufacturer’s warranty would expire on December 31, 1960 (more about this later). Some have no stamp at all, and some have been known to have typos with dates that are almost certainly wrong. For those with no stamp a few were accidentally released without a stamp, and some were made early on before Wilton added that feature.
One thing to know from the outset is that the date stamp isn’t necessarily a manufacturing date because castings sometimes sat unused for months or years, so a vise could have been date stamped long after it was cast. Wilton stopped making vises in their Chicago facility in 1957, but vises with Chicago castings have been found with date stamps more than two decades later indicating either the casting mould was used after the move, or they made a bunch of castings before the move that sat idle for years before finally being finished into a complete vise ready for release. Most of these vises are the small 2″ and 2.5″ models that probably never sold in high volume, so most experts seem to think they were cast as a big lot in Chicago and didn’t get finished until they were needed, often years later.
Most people seem to agree Wilton started making vises in 1941 and several sources indicate they were dedicated to military or government contracts until around the end of World War II. Hugh W. Vogl was the founder of Wilton, and he filed for a patent on his vise in August of 1941 after being in business for only a few months. The patent was a Design Patent which is far less complex than a Utility Patent, so it was approved in March of 1942, which is very rapid for the patent process. My personal feeling is that the buildup to World War II probably pushed patent approvals at a faster rate than normal.
What seems to be certain is that from 1941 through 1944 Wilton vises didn’t have a date stamp on the slide key. Starting in January 1945 the slide key would have a release date stamped into the key that generally coincides with when it was sold. A few years later, Wilton changed the date stamp, as well as how they advertised their product guarantee. Current data suggests that starting in late 1954 Wilton decided to stamp the date when the 5-year guarantee would expire, rather than when the vise was released for sale. They added “GUAR EXP” to the month and year date stamp on the slide key to indicate the change. This created some confusion, and enforcing/honoring the guarantee would have been challenging, since it added a qualifier that the vise wasn’t subjected to abuse, so Wilton ended the practice in 1960. In short, it now appears that the date stamp on Wilton vises is the release date unless the slide also has “GUAR EXP” on it. What is fairly certain is that if it has “GUAR EXP” the actual date of manufacture was five years prior to the date stamped on the slide key.
The information I’m relying upon comes from an exhaustive thread on the Garage Journal where people have been posting pictures of their Wilton vises with the date stamped on the slide (or not) for years. One thing that’s hard to ignore is that there were hundreds of examples posted, but not a single vise was found to have a date stamped on it showing 1954, 1955, 1956, 1957 or 1958. That dovetails perfectly with the theory that during that time frame, Wilton was post-dating the slide with when the guarantee would expire, rather than when the vise was made.
In short, if your Wilton vise doesn’t have “GUAR EXP” stamped on the slide, it was released for sale on the date shown stamped on the slide. If it has no date stamped it’s either a mistake (it happened) or made from 1941 to 1944. If it was made between 1941 and 1944 the production date can be narrowed down a bit by looking at the markings cast into the vise.
For the unstamped 1941 to 1944 Wilton vises, there are four variations I’m aware of. The earlier two versions of vises will have “Wilton Tool Corp” on the right side with a line that loops underneath from the first to last letters. The left side will say “Wilton Vise No X” with X being a number like 3 or 4 that coincides with the jaw width. The right side logo on one version will also have the line looping from the first to last letters, but will have “Pat Pend Made in USA” in the middle of the bottom of the loop. The second version will have “Pat Pen USA” with a notch in the body and a large space between Pen and USA in the middle of the bottom of the loop. There is some speculation about the difference between the Pat Pend and Pat Pen versions, but the likely answer is the Pat Pend came with acorn nuts to lock the swivel base, and the Pat Pen with a notch and gap came with swivel locks that had handles. The handles require a bit more clearance, and the easy fix would be to notch the body in that spot. When they added the notch, they lost some letters. The last two variations of unstamped vise have the markings the same on both sides. There is a large, curved “Wilton” in the upper center and below that will be “Chicago” on the left and “USA” on the right. I have seen unstamped vises with the curved Chicago casting both with, and without, the notch for the swivel locks.
If you have a few hours, and want to read a lot more on the topic of Wilton vise date stamps, check out this thread over on the Garage Journal Forum. The contributors there are really the ones who made this brief article possible.
If you have any information to add to the topic I urge you to join GJ and post to that thread, but if you aren’t comfortable with that, e-mail it to me and I’ll post if for you.
Here are unstamped, curved Chicago vises with and without the notch in the body.
Here is a very early 1941-1942 Pat Pen No. 4 and I will add a picture of the right side soon.
Here is a very early 1941-1942 Pat Pend Made in USA No. 4 curtsey of JohnDW on the GJ forum. Thanks John!