Before we begin, I should start by saying the “multi-purpose” is not some strict standard. It’s just an advertising label some manufacturers stick on vises that have an extra set of jaws or features. With that in mind, I will go over some of the different types of multi-purpose vises (sometimes spelled vice) below:
What is a multi-purpose vise
The corny answer is that it’s any vise designed to solve different classes of problems. The real answer is that it means the vise has both a set of pipe jaws and traditional vise jaws. Traditional vise jaws are really bad at gripping pipe. To grip pipe with a traditional vise jaw, you have to clamp down really hard; this clamping pressure distorts the pipe’s geometry (especially pvc pipe), which will throw off any measurements you may have made for cutting or threading.
A pipe jaw allows you to avoid these problems as it is specifically made for gripping pipes.
While most multi-purpose vises are designed to solve the same class of problems, they do have differing levels of modifications and features. I will go over the most common variations below.
Rotating Head Vises
This features just allows you to rotate the vise jaws in a circle AROUND the x axis. In the yost 750 di , this means you can rotate the head of the vise so that you can access either jaw head at any angle. For pipe fitting, it’s sometimes handy to set the pipe jaws horizontal, so that you can hold pipes straight up and down.
This feature allows you to rotate the vise 360 degrees around the base. Most vises accomplish this by placing an inner base plate inside the outer base plate. This inner base plate has two carriage bolts that point straight up towards the sky and poke through the outer base plate. These carriage bolts have locking nuts on them.
To swivel the base of the vise, you unlock the locking nuts, which in turn allows you to rotate the inner base plate of the vise. This in turn rotates the whole body of the vise.
This is a handy features that allows you to work on your stock at different angles. It comes at the cost of making your vise less resistant to shock blows, as this inner base plate may crack and break. This isn’t a problem for the vast majority of DIY’ers. You may consider getting a blacksmiths vise or post vise if you plan on doing any forging in your vise.
A reversible vise is a vise where the stationary jaw has steel jaw blocks on both sides of the stationary structure. In addition, you can pull the movable jaw out of the vise, and reattach it on the other side to make use of the both sides. This allows you to have a vise with 2 different jaw opening lengths. Some reversible vises will have jaw blocks with different textures on each side.