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Thread: makeing a tramming bar
03-10-2007, 08:57 PM #1
what is the best way to make a tramming bar? any other way to square head of vertical mill to table?
03-10-2007, 09:01 PM #2
I always just put a dial indicator in the chuck or collet and sweep the table with as wide a radius as I can. Usually taking the whole indicator assembly off a normal magnetic base works quite well for this.
03-10-2007, 09:12 PM #3
If you want to spend abt.$275.00,I got one of those tramming rings that are on 3 legs.They can sit on the mill table right over the 6" vise with swivel base. They are called E-Z Tram.I use mine with a Blake co-ax indicator,which you should invest in anyway-nothing as handy for centering up holes or punch marks under the spindle.I made a Z shaped arm for it abt.6" long,which fits the E-Z tram's ring size.I like mine just fine.
03-10-2007, 09:16 PM #4
Hmm, tramming bar. Can be as simple or as fancy as you want. Take a 3/8" bolt and clamp it in the vise and hammer it over to around an 83 degree angle and it will work just as good as anything else as long as it is rigid.
The underlying theory is that once rigid, it rotates with the spindle bearings.
Here is one I put some artistic effort into a couple years back
03-10-2007, 09:25 PM #5
new at this stuff. was just wondering if it was as simple as bending a rod and mounting indicator. Just bought a mill and a lathe. got a wedge type quick change tool post with the lathe. I think I need to mill the mounting nut to a T shape to fit the slide. Thanks for the fast replies.
03-10-2007, 09:57 PM #6
Matt, very nice welding on your bracket. All in all a pleasure to look at and no doubt to use.
03-10-2007, 10:09 PM #7
Advantage of the co-ax indicator is that the dial face stays stationary.you don't have to look all around the spindle.And,they are absolutely great for centering up holes,etc QUICKLY.But,they cost a few hundred.
03-10-2007, 10:10 PM #8
Simple tramming bar like Matts is fine Scot, cheep dodge, get yourself a piece of plate glass to put on the table so you don't have to jump the slots.
03-10-2007, 10:25 PM #9
The Indicol 178 is on sale for $34.99 at Enco, their model #891-5414. It's pretty hard to beat that for 99% of what you do on a Bpt.
03-10-2007, 10:27 PM #10any other way to square head of vertical mill to table?
Lets see if I can explain it, get your head close using degree marks or whatever suits your fancy, eyeball it, doesn't matter.
Take your test block, (you do have a test block? a chunk of Al, 2X2X6 or 1.5X1.5X8 or whatever). Slap it in your vise, smack it down good on some parallels, snug it up and take a test cut along the X, fly cutter or a face mill, something that will cut the whole surface of your dedicated test block. Just take a skim.
Pull out the indicator, with holder of your choice and sweep the cut you just made, unless you are superman, and I think I was once, you will have a concave cut. Tram the head so that the low points on the concavity are level. This will get you pretty close, take another cut, and dial it in even further.
What this accomplishes, is that you are not squaring your head to the table or to the vise, but to the actual travel of the table, which is the important thing. Grab the test block along the Y axis, and get the tilt of your head correct.
Now, you can use that test block for all kinds of cool tests to find out what your mill is doing. How level your vise is to the travel, by flipping the block. You can find out what kind of droop and sway you have, what kind of twist, flattest place in the travel on your table. We had one mill that ran pretty flat and then dropped off one corner by about .0015.
I really hope that made sense.
03-10-2007, 11:20 PM #11
The Indicol or a home made version of it is a can't do without it tool for a turret mill.
A tram ring is not the wisest use of the money considering a 1-2-3 block or a planer gage slipped unter the indicator at places will do the same job regardless of clutter on the machine table.
Special built tram bars can be artistic creations or personal challenges provided they are made for maximum flexibility in use. SIP made a dandy where the indicator slipped radially along a rail so it could dial in OD's and IDs plus tram in faces. It wasn't very ccmpact but it was very versitile.
I recently wondered why somone hasn't taken a scale and reader from a defunct digital caliper and installed it on a home-made tram bar. Once set it could be used to dial in a arc to determine the radius, find center between features etc. Gimmicks like this can spawn whole lines of handy manufactured machine tool accessories.
03-11-2007, 02:39 PM #12
Aw,come on! don't knock the donut ring.They are accurate to .000005" if i recall.Now,I'm stuck with 2 of them,so I'LL never admit they're not good!!!
03-11-2007, 03:57 PM #13
One at work,one at home.
03-11-2007, 06:23 PM #14
I use a boring head with a bar mounted sideways. The dial indicator (Mitutoyo .0001) mounts to the end of the bar.
I don't use a test indicator for tramming. My Bestest .0001 only has about 10 thou of travel and bottoms too easy.
03-11-2007, 06:40 PM #15
If you use a .0001" you're going to have to use some "windage" to get the tram right.
IOW, as the bolts are tightened the tram is going to change an amount easily measured by a sensitive indicator on a long moment arm.
So...you have to understand the trends of what's going where and skew in that direction ever so slightly so when the bolts are tight and the job is done, everything is where you like it.
Takes a bit of trial and error to get it right [img]smile.gif[/img]
03-11-2007, 07:39 PM #16
I think a back plunger indicator works very well to tram the head. Face is always toward you so its easy to read. Chuck up with axial support in collet and go to town.
03-11-2007, 07:55 PM #17
Gwilson, If your using a co-ax with a 6" rod stuck out a 90', your only reading within .006 for each .0005 on the co-ax. You can get it closer by eye.
03-11-2007, 08:07 PM #18
Matt, that is correct. It is also important to keep the bolts at least 50% tightened while tramming.
If you ever tilt your head significantly and need a major retram, I find that I actually have to go through the process twice. I start with the "A-axis" (front to back), then the "B-axis" (side to side). Usually the latter throws the former out of alignment by up to a thou. Retramming a second time gets both lined up within .0003" over 12", IME.
Which is actually way more than what the average mill owner needs, considering a standard drill drill chuck runs out .003 (I'm obsessed and ditched all my drill chucks and Lyndex collets in favor of ETM collet chucks).
03-11-2007, 11:27 PM #19
Bobw, that method would assume that the bottom of the vise and the top of the vise are parallel and that they are parallel to the mill table. There are to many variables there for me. Also, if the block is only 1.5" or 2.0" wide and 6" or 8" long how are you going to get it true front to rear?
It is best to sweep the table than something in a vise. A ground ring or plate that goes from front to rear would be ok as long as there are no burrs on the table.
You can take a 1/4" or 5/16" or 3/8" cold roll rod about 8" long and bend a 90deg leg about 1" or 2" long and use an indicator located anywhere along the rod to sweep the table. I use 1/4" rod and it works just fine. If you allow about .020" travel on the indicator on the table it is easy to move over the slots in the table. I always keep the head nuts slightly tight so the head don't move to easy. If you do it long enough it becomes easy to do.
03-12-2007, 12:48 AM #20
Tom,you may be right.Maybe I should use a different indicator and mount.Thanks.I just like the co-ax as I have a lot of neck pain and back pain,and it keeps me from craneing around to see the indicator.There's nothing wrong with the E-Z tram in itself,do you think?