Trammed the mil yesterday

I could not get it better than that. Spent 10 minutes on that final adjustment and nothing improved.

i

I will try using the mill, trammed as it is. This is a "many times" improvement over what I had when it was untrammed.

i

Jon, I wonder if a circle, milled on a moving table, represents a true reference surface, or not. I used the top of the Kurt vise as a reference surface.

It was not "really hard", like changing a transmission on a car on a hot day, but after a while I hit a virtual wall and could not improve beyond 0.001" over 4 inches swing.

i

This was the best that I could do.

I will try to face some piece of material and see how it looks with the head trammed.

There is a eccentric cam on one of the four bolts. This is what I used.

i

BTDT, frustrating is the word.

A few suggestions if you go for perfect.

Bolt a thick plate to the table. Use a large face mill to skin cut it down to a true surface. Note, if its off; use only the center of travel for your indicator.

For that last bit of adjustment leave the bolts *almost* tight and use large levers to move the head an RHC. If you have the style head attachment I think you do, changing Y would be damn near impossible, X not too bad.

My check was to skin cut that same plate again, keep going till the facemilll leaves a great surface

Karl

Ignoramus16551 fired this volley in news:ncSdnaOi2pxlDGTQnZ2dnUVZ snipped-for-privacy@giganews.com:

It's just WAY faster. The better ones can, themselves, be "trued" prior to starting. Then you don't have to do the 180-swing thing until you're tweaking out the last half-a-tenth.

LLoyd

Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:

It's a CNC, Gunny. Lacking a 4th or 5th axis, all it can do is 2.5D. It can hardly be called a manual machine, although his EMC work allows joysticking.

Unless a CNC has head gimbaling under control, the ability to tilt the head isn't of much use.

LLoyd

Ignoramus16551 fired this volley in news:o_-dnTLax4P2BmTQnZ2dnUVZ snipped-for-privacy@giganews.com:

Ig, I've got mine pretty close, but I have ONE 1" carbide endmill that someone crashed into a workpiece once while it was not running (cause it's not busted). However, they must've bent the shank ever so slightly, because it basically cuts on one tooth, all the way around.

I faced some work and took it to a friend who has a surface roughness tester. He says it's off less than 1.5 microns, but it still _looks_ like an old fashioned "engine finish"; "jeweled", as it were.

Me... I doubt the 1.5 microns, because I don't think the old spindle bearings run THAT true!

LLoyd

LLoyd

Are you sweeping a tiltable head to zero, Ig? When I hear the term "Tramming", I think zeroing the table to the head.

(Just clarifying my newbieness, too. What's the terminology, guys? It wasn't covered in Briney's _The Home Machinist's Handbook_)

-- Happiness is when what you think, what you say, and what you do are in harmony. -- Mahatma Gandhi

Since you aren't swinging an indicator around, you aren't introducing potential error in the indicator mount / joints during movement. Since you aren't swinging an indicator around you're staying at the same contact points on the table or vise so you aren't picking up variations in that surface either. Since you see both indicators at the same time you don't have to remember readings between swinging an indicator between sides so adjustment is vastly faster. Also, for manual mills, you can set the head at angles quickly and accurately using a sine bar and zeroing off of that. I think it's worth the money for the time and fuss it saves you.

It's not a tiltable head as in a normal use axis like a regular Bridgeport. It's a CNC with a fixed head, but that still needs to be fine tuned to ensure its square to the table and as Iggy noted, it has some eccentric cams in the head mount to allow that small amount of adjustment.

It has a 4th axis, actually.

Yep. The head is bolted tight and does not move.

i

The head is not tiltable like on a manual Bridgeport, but there is a little cam that lets me "tilt" it by 0.5 degree or some such, just to do tramming.

i

>

Pete, what do you think about using the top of a Kurt vise as a reference surface?

Keep in mind that my mill table is covered by an aluminum plate.

Also, I am thinking, that this is a better spindle square:

Your opinion?

i

Set one to zero. Turn 180 set the other to zero. Turn back and adjust. I crane my neck once. The way Jon does it is better, but I have not the patience for that, and it would require craning my neck every which way to read it.

I used to do it with one indicator on a bar and I did crane my neck around to do it. With two its faster. My machines are not very rigid, and my high speed spindles are just in aluminum clamp mounts so its all a compromise anyway.

What's an SPI?

>>

I think that could introduce errors if the vice is not solidly locked closed/down. The vise way surfaces with the vice open are probably better since those are the surfaces your part or parallels supporting your part reference off of generally.

The spindle square is available in two versions, take a look at I'm not sure the version with the 0.0005 indicators is really necessary for normal use, since you get to watch both indicators at the same time you can visually get the readings matched to less than the dial graduations anyway.

I used one of those mills about 20 years ago. If I remember the feet contact and adjustments on the floor also will affect how true the head is.

You should be able to get it closer than .001" for a 4 inch sweep. You should be able to face a piece of aluminum with a 4" flycutter without any visible step showing between passes.

-jim

SPI = Swiss Precision Instruments, Inc.

Actually, to half of the difference.