One Man's Vices

[AussieJimG]

When I did a course at the local Technical College a couple of years ago, one of the exercises was to make a rail vice from 25x25 cold rolled steel. This vice was so useful as a milling vice that I have now made a smaller one from 20x20 CRS.

Here are the drawings and a video (I hope) and I will follow this with some construction photos.

[ame]http://www.youtube.com/watch?v=y8PYsMuimqY[/ame]

View attachment Rail Vice 20mm.pdf

 

[Philjoe5]

Good work Jim. I must make one.

Cheers,
Phil

 

[jwcnc1911]

Great work Jim. I commented on your YouTube video. I have a 4 inch Kurt style vice that I cut a keyway in the bottom to line up with the table slots. It's real quick on and off and lands within a couple tenths every time.

I set up a piece of stock, milled it so I knew it was parallel, clamped the vice on it upside down, cut a 3/8in keyway so that it was snug enough to stay in (I had to gently coax it in with a deadblow). I've got to the point where I never even check it.

I think many people will benefit from your video, are you going to post drawings?

 

[Herbiev]

Thanks for sharing Jim. Great work

 

[Wizard69]

Nice vice!

The first thing I thought was that the vice would be great for a drill press.

 

[AussieJimG]

Thanks Phil, Herbie and Wizard for the comments.

Thanks also JW, and the drawings are in the first post. I like the idea of cutting a keyway in a good quality vice for quick setup but this one is a bit more versatile (like setting up vertically) and it slides in the Y direction which is handy for some setups.

Wizard: Yes, it would be good for the drill press and I have had thoughts of making a smaller one to fit on the rotary table (this one is just a bit too big).

Construction photos will follow.

Jim

 

[AussieJimG]

While not strictly part of the 20mm rail vice, the accuracy of the vice depends on the accuracy of the squares for setting up. And having accurate squares reduces the need to index everything during construction. So I started by truing and checking each of my squares.

A bar was setup and indexed along the y axis and each square in turn clamped to it while a truing cut was taken along the x axis. Runout on each of the squares was measured at less than 0.01mm.

Then the major components were cut from the bar with the bandsaw and marked roughly with a felt pen to show the cuts to be made and their orientation. I find that this helps to avoid those gross errors like making two of the same item.

The item numbers subsequently changed when I altered the design to eliminate the spacers shown at the ends of the rails from the final device.

 

[Philjoe5]

Jim,
I never actually measured how far off my inexpensive squares are. Did you ever take a measurement? Next time I'm in the shop I'm going to check mine.

Nice build log going on here BTW

Cheers,
Phil

 

[AussieJimG]

I don't recall how far out the squares were Phil, but I know that I checked three squares against one another and worried a lot about whether I was doing the right thing by truing them on the mill; what if the mill was out of square etc.

Now, on with the show. I set myself the task of building the vice without using a vice so somebody could do it to make their first vice. In retrospect, this was probably the right way to go as it meant that everything was setup with the table as the reference.

The first use of the newly trued small square was to set a vertical stop on the angle plate to square the ends of the cross bars Items 1, 2 & 3 and to cut them to length.
One end of each was squared and then they were put back in the jig so the other end could be squared and brought to length. The z axis was left unchanged for all of them which should have resulted in them all being exactly the same length.

The last photo shows that there are minor differences. Not critical to the project but annoying and a bit mystifying as well.

 

[AussieJimG]

The Spacers and Retainer – Item 5

It is critically important that the spacers all be the same width since two of them hold the rails apart and parallel and the other controls the moveable jaw.

The spacers were held together with double sided tape to prevent relative movement during machining. They were then clamped to an angle plate set square with one of our newly trued squares and machined using a shoulder mill.

They were then reversed for the other side to be machined. The actual width is not critical, neither is the dimension of the small extension at the bottom both of which can be measured with a rule; the critical element is that they all be the same.

You can see from the photos that the critical width of the spacers was not the same: 9 measurements taken (3 across each spacer) ranged from 30.09 to 29.92 – a variation of 0.17mm which is far to large.

From the measurements, it appears that the spacers tilted sideways during machining; neither the bar nor the adhesive preventing the movement. I was a bit apprehensive about the clamping bar only applying direct force to the outer spacers but felt that those outer spacers would hold the central one sufficiently. I did not consider the possibility of rotation between the spacers.

So the group of spacers was clamped as shown and a cutter run down both sides to just remove the marking blue. After that, all the spacers measured 29.66mm – slightly under the nominal 30mm dimension but at least all the same.

In retrospect, they should have been clamped as shown in Photo 71 in the first place but along the y axis instead of the x axis. Using the x axis would have enabled them to be squared up and possibly set against a flat bar to hold them square. Clamping them as shown would hold them securely while permitting the width to be measured with a micrometer.

 

[AussieJimG]

Item 6 – The Rails

For the next series of operations, a bar was carefully indexed along the y axis as the reference.

The rails were held together with double sided tape and squared to length.

While still held together with the double sided tape, the 5x5 rebates were cut. The width of the rebates is not critical so they were cut together with a 10mm slot drill. The depth itself is not critical but it must be the same on both rails – this is the depth from the top of the rails to the top of the rebate and it determines the amount of tilt on the moving jaw when it is tightened. Cutting them together ensures that the depth is the same for both and also that the surface finish is clean.

The rails were now separated and the mounting slots cut. These slots are in the centre of the rails and although the dimension is not critical, care was taken to orient each rail with its top side against the bar so they were both the same.

 

[AussieJimG]

More Work on the Jaws

The holes in the fixed and moving jaws for mounting the soft jaws, the hole in the moving jaw for the screw and the hole in the screw jaw for the screw are all at the same distance from the top of the jaws. Once the quill was set at this distance, all of the operations were performed to ensure that the distances remained the same.

 

[AussieJimG]

Relieving the Moving Jaw

The setup lent itself to relieving the moving jaw so this was done next.

Slotting the Rails - A Critical Operation

The next series of operations is critical to the accuracy of the final product so a trial was conducted of the second setup to ensure that it could be put in place without disturbing the work.

The rails are separated by the spacers cut at the same time as the retainer and the slots cut for the fixed jaw and screw jaw.

These are cut so the jaws are a neat fit.The slot for the fixed jaw is particularly important. With the right hand rail pressed to the bar that has been indexed along the y axis, the slot should be exactly along the x axis. And with the left rail held parallel to the right rail by the spacers, the final product should be square.

Mounting Holes for the Jaws

With the rails still held in place the fixed and screw jaws were inserted in the slots cut in the previous operation and all of the holes cut.

Each of the screw holes was completed without moving the quill – spot drill, clearance drill, tapping drill and counterbore. And then the holes for the pins were drilled through the jaws and the rails.

And here is where I made a mistake. I should have tapped the holes and bolted it all together before taking it off the mill. My concern at the time was that I wanted to use Loctite on the screws and the pins but I needed to use tapping fluid to tap the holes. In retrospect, I could have cleaned the holes after tapping.

Despite all my care in the machining, when the vice was assembled, it was not square. It clocked about 0.04 out along the fixed jaw. I actually had to re-establish the setup and tap the jaws and rails into position while clocking them in order to get it all square. It would have been much better to do it at the time.

 

[AussieJimG]

The first photo shows the rails being tapped. They should have been done in situ.

Then when I put it together, I found that it was not quite square.

And it was time to tap the soft jaw mounting holes which should have been done long ago of course.

 

[Philjoe5]

It's looking good Jim. Great photo documentation makes it easy to follow along.

Cheers,
Phil

 

[AussieJimG]

Thanks Phil.

Finishing the Retainer

Drilling the mounting holes for the retainer and the hole for the pin. These were drilled through into the moving jaw. The pin holds the screw in the moving jaw.

Facing the retainer to depth. This is another critical dimension - it is the one that prevents the moving jaw from tilting when the vice is tightened.

The depth was marked from the moving jaw in the vice and the retainer was cut down to there, leaving it a bit long. It was then removed and the gap measured with a feeler gauge. The retainer was then replaced and the quill adjusted to remove the remainder. The result was a snug fit.

 

[AussieJimG]

The screw is a length of allthread and the handle is a simple turning and knurling task. I am sure you don't need photos of them.

Checking for Accuracy

The vice was setup on the table using the square and clocked. It clocked to less than 0.01mm across the width of the jaw. A very satisfactory result.

It was not clear at the time just how repeatable this measurement is – whether setting up with the square would always result in this accuracy. But the vice has now been in use for some time and is still accurate.

But it can still be clocked and tapped into position if required. Or pieces of aluminium can be screwed to the jaws to act as soft jaws and a cutter run across them if this is more convenient. Either way, this vice can be used to obtain as much accuracy as the milling machine can deliver.

The Result

And here it is together with the clamps that hold it to the table. The clamps are a section of 50x50x6 angle iron. They also fit the 25x25 vice and some ER collet blocks I made.

And that's it folks. Thanks for watching.

Jim