China Made Mini Vise Upgrade

Prusa 3D printers, what's not to love about them? Not one thing! They are absolutely the best on this planet. You know what else I love about Prusa products? They are not made in China. Thank you Josef! That is why we can use our Prusa 3D printers and correct and/or transform just about any brand new inferior product into an actual working product. Not that other printers could not do it, but Prusa just does it better.

Enter this mini vise upgrade. I chose PETG for this project because I wanted to have just a bit more heat resistant material for close quarter soldering and didn't think PLA would hold up. If you have  one of these vises, you will want to take advantage of this upgrade. I highly recommend adding at least 5 perimeters and additional layers top and bottom (at least 6 layers for strength). WARNING: Some filing and/or sanding will be required. Taking a look at the stock version of the mini vise, the adjustable jaw (in my case) rides in a slot that is about .030" too wide and binds as it advances or retracts the jaw causing as much as 4.5mm lateral movement of the jaw (arrgg). Also looking at the lead screw, it has a slot cut between the end section of the threads. The screw that secures the adjustable jaw to the frame protrudes through and secures the lead screw to the jaw (if this all makes sense). While advancing and retracting the lead screw, the lead screw would also binds against that particular screw which compounded the binding actions. Needless to say, the stock version is just utterly useless. I did not set out to purchase this mini vise directly because it came with a pin vise I ordered from Amazon. 

First I designed a guide for the adjustable jaw. The guide has one layer thick walls that ride against the inner slot to aid in smooth action. Looking at the bottom of the frame in one of the photos you will notice a spring that I attached to the new guide. This spring serves a couple purposes. Mainly it provides tension toward the lead screw and eliminates any binding from the screw that locks the jaw onto the lead screw. Second is it pulls the base of the jaw face downward keeping it in alignment with the frame jaw. NOTE: the addition of a hole drilled for a #4-40 machine screw to attach the spring to the frame and the use of a Dremel to carve out a bit of metal for the spring to travel are the only invasive modifications to the vise. Filing the adjustable jaw (on both sides) where the guide fits onto (See photo) is required in order to make a snug fit. If not filed, the thin walled sides of the guide will bulge where it rides in the frame slot. File the jaw until it just fits snug without bulging the two thin walled sides.  Also the rough edges of the slot where the guide slides in will also have to be lightly filed or sanded. File or sand until the guide just starts to slide smoothly. 

Next I designed the interchangeable jaws. May I suggest that you rotate the jaw (top side down) in your slicer 180 degrees with a couple of itty bitty supports on the clips for better printing. The face has a grid pattern that provides a very good grip especially using PETG because its a bit softer than PLA. The new jaws allow for near perfect parallel alignment with one another. The stock screws that came with the vise for holding round objects will have to be replaced with longer screws (#10-32 machine screws will work) at least 22mm - 25mm (.875" to 1.00") length. The cavity inside the jaws will allow for longer screws. I did not have any long flat head screws on hand so I had to use pan head screws and made some beveled spacers to prevent the top of the small orange things from mushrooming while tightening. 

I wanted to be able to mount this vise in my portable bench vise so I designed a crude stand of sorts that adds a bit of stability while freestanding on the bench surface or can be clamped in my bench vise. I used (4) 10-32 brass inserts on the bottom side of the stand for the (4) #10-32 X 1" screws. The holes for the brass inserts in the stand has a diameter of .245" and are .375" deep and used solder iron @ 240C to insert. Four (4) printed inserts are used in the vise frame for the #10-32 screws (at least 25mm - 26mm length (1.00")) to attach the stand to the vise frame. I centered the holes in the plastic inserts for simplicity, but because of the original design of the vise itself, its mounting holes (slots) are not symmetrical and thus the stand will only fit one way onto the frame properly. The stand has four (4) recessed areas on the bottom for self adhesive rubber feet.

Now the vise operates pretty smooth and functions very well. It is not built for heavy or even medium clamping, but I think it will serve my purpose just fine which will be for soldering, very light drilling and as a third hand. I hope this will be of use for anyone. Btw, you will need to file down any imperfections in the casting on the jaws in order for them to fit good and snug, believe me there will be imperfections. There are different looking vises on Amazon that look similar and have what appears to be black powder coated lead screw. Not sure if this is the same vise with just a powder coated lead screw so use at you own risk. If you have one with shiny lead screw like mine, then all the parts should work just fine. This post is not meant as a tutorial, but summary of the steps I took to modify this vise. Use any portion of this post that you will. If you are not comfortable with the entire modification, then just print the jaws, but you will need longer screws if you want to use the small orange things on top of the jaws and you will need to file some places on the jaws so that they fit properly, but should only be very minor filing. Just remember that all cheap tools are not created equal, so the risk is your own. 

 ;p