A Drop-In Bench Vise Jaw Jack

[rgsparber]

Sometimes I need to clamp a small piece of stock at one end of my bench vise. Without adding any packing to the other end, the jaws tilt resulting in poor clamping action. Adding packing of exactly the right thickness solves that problem. But I don't always have such packing. One solution is a variable thickness packing block or… a Jaw Jack.

If you are interested, please see

https://rick.sparber.org/DropInJawJack.pdf


Your comments are welcome. All of us are smarter than any one of us.


Thanks,

Rick

[madokie]

pass ,,,too complicated and parts to loose,, how about a dozen 5/8 flat washers stacked on top of each other and loosely riveted or bolted together, at the far edge away from the center hole.. u just put how ever many washers u need to hold the gap open and u can run a thick wire or rod through center hole on top of vise jaws to keep washers in place while u hold other part and tighten vise..

[mklotz]

pass ,,,too complicated and parts to loose,, how about a dozen 5/8 flat washers stacked on top of each other and loosely riveted or bolted together, at the far edge away from the center hole.. u just put how ever many washers u need to hold the gap open and u can run a thick wire or rod through center hole on top of vise jaws to keep washers in place while u hold other part and tighten vise..

Thank you for your post.

Sometime ago I acquired more brass key tags than I will ever need and so decided to make an adjustable spacer with them...



I've used it numerous times on my milling block...



but, now, with the benefit of your post, I realize it would work perfectly as an adjustable vise shim.

[madokie]

good ,,just what i was thinking ..

[DIYer]

Thanks mklotz! We've added your Adjustable Vise Shim to our Vises category,
as well as to your builder page: mklotz's Homemade Tools. Your receipt:

Adjustable Vise Shim by mklotz

tags: vise, spacer

[DIYer]

Thanks rgsparber! We've added your Adjustable Bench Vise Jaw Jack to our Vises category,
as well as to your builder page: rgsparber's Homemade Tools. Your receipt:

Adjustable Bench Vise Jaw Jack by rgsparber

tags: vise adaptations, spacer

[rgsparber]

I realized from "madokie" and Marv's comments that I had not fully explained the purpose and how to use the jack. My goal is to have packing for the vise that prevents any tilting over a range of stock thicknesses. A stack of disks nicely solves the problem of getting close to a given thickness but, on average, will permit a tilt equal to 1/2 the thickness of a disk (assuming they are all the same thickness).

The stack of packing plus the jack solves the problem. But since I don't have a stack of disks and am always looking for alternate ways to do anything, I made a stack of blocks with a binary ratio of thicknesses: 0.5", 0.25", 0.125", and 0.063". The jack takes up 0.375" to about 0.5". This means I can create any exact thickness from 0.375" to about 1.4" and never use more than 5 pieces.

I'll update the article with proper acknowledgments.

Thanks,

Rick

[mklotz]

You're absolutely correct about the stack permitting a slight tilt proportional to half the disk thickness. Fortunately the disks are thin and my aged vise is very sloppy.

My compliments on having the insight to use a binary progression of spacers. I've been advocating that for a long time. As an example, DI extenders often come in a threesome of 1, 2, 3" sizes, which permits all the inch integer combinations up to 6"...

1 = 1
2 = 2
3 = 3
4 = 1 + 3
5 = 2 + 3
6 = 1 + 2 + 3

but a binary threesome of 1, 2, 4" sizes permits all the combinations up to 7"

1 = 1
2 = 2
3 = 1 + 2
4 = 4
5 = 1 + 4
6 = 2 + 4
7 = 1 + 2 + 4

In a foursome of spacers, the difference becomes greater.

1 + 2 + 3 + 4 = 10
1 + 2 + 4 + 8 = 15

and similarly for larger collections.

Also, in binary collections with more members one has the advantage of simply writing the desired size in binary to determine which spacers to use.

[madokie]

exactly,, use a stack of washers with different thicknesses, to get your desired size, u can also use a short NF bolt(face off bolt head in lathe) and 2 nuts,run one nut (standard lenght or get a longer nut )to the end of bolt and use the second nut as a jam nut,u should be able to get your size easily within 010,, just use a magnet to hold bolt in place on vise..another way to do this is to drill and tap a hole all the way through vise and jaws and use a long bolt with a jam nut, a bit labor involved, but if your going to do this a lot..now if your going to be doing a lot of the same size parts , get a extra pair of small milling step jaw clamping height blocks and machine to size..or just make up some spacers to your needed size..

[rgsparber]

The design has not finished evolving. I found a box of old lock parts that were perfect for making a stack of equal thickness bars. I really like how the bars fill the gap between the fixed vise jaw and the jack. They naturally filled this gap by flopping down. Although it has a lot more parts, it is much easier to use without having to think much about it. The article has been updated with this iteration. Proof, again, that we should never throw any metal away. Also proof that all of us are smarter than any one of us.

Rick