Keeping your vice straight

[Bogstandard]

A lot of people already know about this little exercise, but there may be a few who don't.

When you remount your vice to the mill table, it should then straightened up, by running a DTI along the fixed jaw (I prefer to use a parallel mounted in the vice) by feeding backwards and forwards on the X axis. You then gently tap the vice until you get the same reading at either end of the jaw, then the vice is locked down and everything is rechecked again. At times this can be a real PITA, and normally takes about 10 to 15mins to get it spot on.

This little exercise, if done carefully, can do away with the vice alignment check completely

A couple of years ago, I bought a new mill and a 6" vice to fit onto it. Everything else, rotab, spindexer, got an auto aligning bar, but I never got around to doing the vice, until yesterday.

You will have to excuse some of the pics, the battery was getting low in my camera, so I couldn't use the flash to counteract camera shake.

I was lucky in that I had some ⁵/₈" bar that was a perfect fit into the T-slots on my mill table, it needs to be pushed into the slot, not drop thru. If you don't have such bar, you will have to machine some up until it fits perfectly.
Another bit of luck was that I had my 4 jaw self centring already on the lathe, so I just parted off a bit over 4" long. That saved me some armwork.



This shows the bar, it should self support in the T-slot. In fact, you should make up a couple of bars like this so that you can square bits up along the slots if you are working without the chuck, or even a couple of bits of round stock that sits up above the table face. They really do save a lot of time. I have a couple of brass bars that I machined up when I first got the mill.



The first job was to get the ends machined up and the bar to the correct length.



Then I went along every corner edge with a roundover bit, you could use a countersink bit if you are careful. The reason for this is that I don't want any damaged sharp corners over the coming years holding the bar off the correct position it should be in in the T-slot.



After the cutting burrs were cleaned off, the centre of the bar was found in both the X and Y and two holes were drilled and recessed at 3" pitch for two 6mm cap screws.
The register bar was now finished. Time to start hacking away at the vice.



First off, I mounted my two brass aligning bars into the T-slot, then I turned the vice upside down and tightened up the jaws onto the bars.



Then a clamp either side to lock the vice to the table. The fixed vice jaw is now in perfect alignment with the T-slot.



The pictures of cutting the ¹/₄" deep by ⁵/₈" wide slot were too bad to be used, so I will try to explain it.
I aligned the ¹/₂" cutter to the centre of the clamp bolt slots and cut right the way across the vice, then by going ¹/₁₆" either side of the slot already cut, very gently at the end, until the bar that I had made previously was a push fit into the slot.
Then comes this picture, which shows me using a countersink tool to put a nice chamfer down each edge of the slot, this again is to stop having sharp corners that might cause problems in the future.



Next off was find the centre line of the slot, and the rough centre of the vice, then two holes were drilled and tapped on a 3" pitch.
This shot also shows how nicely the slot I had cut matches up to the cast in slots for the holdown bolts. I need nothing out of alignment that will interfere with the alignment bar sitting perfectly in the T-slot. Even a binding holdown bolt in the slot can push everything out of wack.



The bar fitted perfectly in the slot.



The batteries then gave up in my camera, so I will have to show you the final results tomorrow.

Just to explain a little.

These are dimensions I used are for my mill table slots and vice. You will have to work out the dimensions you require for your particular setup.
I can honestly say, by doing this, it inspires confidence in knowing that your machine is set up to the best it can be, plus also, if you are doing some heavy cutting, you are guaranteed that the vice will not be knocked out of position.

It might seem to be a bit drastic, hacking away at your most probably new vice, but if you take things very steady, it is a job that most people can do.

Now to get those damned batteries charged up.


Bogs

[AdeV]

Nice work John. I keep meaning to do this exercise to my vice as well, but somehow I never get a round tuit. Mind you, my vice is so far out of square in every other direction, I might as well do without it at the moment....

[tumutbound]

Another vital project to add to the ever growing list.

This should save me 30 minutes at least when fitting the vice   

[Brass_Machine]

I was just swearing at my vice as I reset it up tonight. I am doing this very soon!

Thanks John

Eric

[Bernd]

My vise for the Bridgy is on the list to have that done too.

Just to lazy right now. 

Bernd

[NickG]

Have heard the principle before John but never seen it done - this way looks gauranteed as long as you get the fit good. Suppose you have to assume the T slots on your table are parallel with the dovetails - is that necessarily the case? You'd hope so but not sure about my chinese lump!

Nick

[crabsign69]

bogs u always got something. now i need to figger out how to cut a slot in my vice its a hermann schmidt vice and very friggin hard steel i cant cut it with what i have any ideas i could use

[Stilldrillin]

One day, I'm going to mod my vice too.....

And make an adjustable vice stop.....

One day...... 

David D

[Bogstandard]

Batteries charged, now going out to the shop to tidy everything up.

Nick, mine is a chinese lump as well, but it very easy to check, mount your dti in the chuck and drag the end along the inside edge of one of your slots (clean it out first though). Nowadays, they should be perfectly in track.

Crabs, there is always something to do or make in my shop, and I am sure, unless you are one of those people who can afford everything, you will have lots to do as well.
To cut the slot if it is so hard would really require a grinder, but that cannot be done as you actually use the machine itself to ensure it is a perfect fit.
I have seen toolmakers vices like that before, in fact the one I have for grinding and tapping jobs is one, it is as hard as glass. It was over 500 squid when it was bought in the mid 80's (not by me BTW).


Bogs

[Bogstandard]

I'm going to have to get my brain around this new camera, most times I can get really good shots, but last night and tonight they have turned out awful.

So the vice was dropped into the slot and clamped down, the bolts had plenty of room around them so no binding. Then I put a parallel into the vice jaws, and took a reading of it's face. I do this because sometimes vice jaws get a little battered and can throw out the readings.

Anyway, the pics are just about good enough to see the results, which to me were rather disappointing, a full stroke of about 5" gave a runout of 0.0001". I even belted the tail end of the vice with a rubber mallet, and it didn't even change. I was at least expecting some sort of fight from it, but it gave up with no resistance.







Just a word of warning if you use a parallel for checking like I do. Most reasonably priced sets of parallels are usually fairly good height wise, but sometimes the thicknesses leave little to be desired. Some of mine are at least a couple of thou out over their length. I have one that I keep specifically for high precision work and have owned it for many years, and it is perfectly parallel all round.

So that's it, a bit of an anticlimax I'm afraid. But at least I now know that I can just drop the vice on, bolt it down, and be somewhere near.

Goodness knows what I will get up to in the future.

Bogs

[John Stevenson]

For anyone who has one of the hardened vises you can make one of these.



Simple horse shoe shape that clamps in the vise and the two ears drop into the tee slots.
they don't even have to be a good fit as long as you keep the vise pushed or pulled so the jig registers.
If when fitted to the jaws they don't line up with a slot , then just use packing to get it in line.

Before you make one check your other vises and make it so the same jig can be used on all sizes [ up to a limit ]

John S.

[Bogstandard]

Very good idea there John.

That would be perfect for those toolmakers vices that don't have holdown slots, but a sort of clampy bit on the side.


John

[crabsign69]

john  thats what ive been using to get my vice striaght and it works good but i like bogs take on that vice  perhalps when money is better ill get a vive i can mill into.
or maybe ill buy the metal and make my own better yet. 

[raynerd]

I`m digging this older post up because I`m wanting to do this to my vice. I`ve made my piece that fits perfectly in the T slots but my problem is my vice already has a slot and holes drilled and tapped. From what I can understand, this method works because holding the vice upside down clamped to the bar means that cutting the slots aligns with the T-slots and makes it square. My slots in the vice are already cut and they are wider than my T-slots on the table. Infact - there is both a slot with tapped holes in both axis of the vice. Do some vices come with these slots cut or is it likely that a previous owner has done this as it was kindly donated to me. It is an excellent vice and for the last few months when I`ve been planning on doing this I presumed it would be easier for me as the slot is already cut and holes tapped - now I realise I can`t follow this method because of it!! 


Now a bit  but on the topic of vices, can I also ask - is the big lug at the very top of the vice necessary? Only I really like this vice but that lug gets in the way of my mill column and takes about a full 3/4" of travel off the Y-axis.

Any advice welcomed.
Chris

[jim]

i'm glad you dug this up!!

had to do one of them "five Min favour" jobs today with the rotary table, spent far longer lining it all up than doing the job!

i'll get some similar done on it ASAP!

[Bogstandard]

Chris,

Vices are usually held in the Y axis purely because you are then not limited to the length you can hold, whereas if you have the vice mounted in line with the X axis, then you can only hold material as long as the vice can open it's jaws to.

If you are never going to use the vice in the X axis, then that lug can be cut off, as you will be using the two side lugs to hold the vice down.

With regards to using the groove you already have in the bottom of your vice.

As long as it is in line with your hold down lugs, then what you do is to put a good fitting bigger bar into the slot you have, and tighten it down. Then by taking some off each side of the bar, bring it to the same width as the slots in your table.  You will in fact be making a t-bar.
Make sure the bolt heads you use are smaller than your table slots, and don't dig too much out of the bottom of the vice casting as you skim down the sides. Verniers are no good for measuring the width for going into the slot, they are too inaccurate, you must use a mic and work to a tight tolerances otherwise the fit into the slot won't be good enough for keeping the vice spot on. The more time you spend on getting the width spot on, the more accurate your vice will be held in line.
I have had my vice off a few times since I have done it, and just locating it into the slot and tightening down, there is absolutely no runout at all. So now I can trust it so much, it does not need to be checked each time. That saves at least ten to fifteen minutes during setups.


Bogs

[75Plus]

I`m digging this older post up because I`m wanting to do this to my vice. I`ve made my piece that fits perfectly in the T slots but my problem is my vice already has a slot and holes drilled and tapped.
Chris

Chris,  I had the same problem so I solved it by using material that was an exact fit for the existing slots on the vice and then machine it down to fit the T slots. I had to mill off about 1mm.

Joe

[marfaguy]

Hi Chris,
I'm planning on doing this mod this weekend. I've been thinking about this and
wondered what my plan "b" would be in case I messed up and made the slot in
the vise too wide. I always like having a plan b. Anyway I decided that if missed
the vise side slot width by making it too big, I would go ahead and make it very
much too big (maybe .10" or so) then mill a new brass bar to first push fit into the vise side then carefully
re-mill one half to push fit into the table slot. In other words, the bar would have a step in it
so it has two different widths. Would something like that work on your vise? Might also be
away to fix it if the previous owner wasn't careful and didn't get the vise slot perfectly parallel
to the fixed jaw. In still other words, Do as Bogs suggested with the bar in the vise upside down
then clean up the slot a bit if needed, then make sure the slot width is uniform. Then make a
new bar with the appropriate change in width so it's a push fit on both sides.

I used to something similar when making mortise and tenon joints in wood. I always found it easier to
fit the tenon to the already cut mortise which you can't really do when plowing out the vise side slot in this mod.

 I would think a similar approach could be used on the other axis if desired.
-Charles

Edit:
Looks like Bogs beat me too it.  
Second edit:
Not only did bogs beat me to it but Joe did as well and about four days ago.
Note to self, read the whole thing before replying.

[raynerd]

Digging up this blast from the past for the second time!!!

I am GOING to do this but John took down his pictures. Are there any other threads on the net which show this method with photos. I can't remember the process without them despite the personalised message from John in one post.

Chris

[Stilldrillin]

Is this any use to you Chris? 

http://madmodder.net/index.php/topic,7643.msg82113.html#msg82113

David D