[outsider787]

I just machined some angle brackets on this BF20L that I just got, and after putting a machinist's square to the part (also placed the part against a 123 block while sitting flat on the table), and the machined 90deg is not 90.

Machining process: Faced off one side of the bracket (while in a vice).
Then clamped the machined face against the stationary face of the vice and used a rod on the other side of the other side of the part between the vice and part. Then faced off the next face.

How do I figure out how what's out of true, and how do I go about adjusting it?

[photomankc]

Check out Hoss' videos on youtube on tramming. He presents a very good method for getting it about as good as it is going to get to include squaring the column. I think the procedure Hoss shows is nice since it starts by getting the spindle square to the column travel and then builds from there. Another option I've seen and used is to run the head up and down indicating up a machinists square clamped to the table. Get the column square to Y/Z first and snug that up, then switch to indicating the X/Z and tap the column into alignment and secure it. Carefully and equally tighten all the screws and confirm again. Then tram the head to the table.

Other things that can factor in are the head nodding back a little under cutting load. The vice itself may not be square to under 0.001". How bad is it?

On mine the most troublesome issue is the table is sloped by 0.0015 or 0.002" from back to front in the Y. I was still getting stair steps even when the spindle head was shimmed to point zip tram error front to back. Turned out that the part was rising in relation to the tool as the tool moved forward. So I shimmed the vice and and trammed my head to it's bed. Lo and behold, no more shim needed for the head and I can just barely make out the interface between 2.5" face-mill passes. So it all depends on what you start off using as a reference and how perfect it is.

Irritating that the Y is like that yet the X shows less than that much error over more than twice the distance.

[SCzEngrgGroup]

I just machined some angle brackets on this BF20L that I just got, and after putting a machinist's square to the part (also placed the part against a 123 block while sitting flat on the table), and the machined 90deg is not 90.

Machining process: Faced off one side of the bracket (while in a vice).
Then clamped the machined face against the stationary face of the vice and used a rod on the other side of the other side of the part between the vice and part. Then faced off the next face.

How do I figure out how what's out of true, and how do I go about adjusting it?

How did you align the vise to the table?

Regards,
Ray L.

[outsider787]

How did you align the vise to the table?

Regards,
Ray L.

Only alignment I did was to make sure the stationary part of the vice was parallel to the table motion direction.
I stuck a dial indicator in the drill chuck, pointed the indicator to the stationary part of the vice and moved the table side to side.
After a few times, the dial read under .001 over the length of the vise face.

I did nothing to square the vice face to the table surface.

[SCzEngrgGroup]

So how far out of square was the part you cut? *IF* the vise was truly set parallel to the machine axis, and your part did not come out square, then the ONLY answer is the X and Y ways in the saddle are not square to each other. If so, the only solution is to remove it, take it to a machine shop, and have it milled square.

How confident are you that your machinists square is really true? They often are not. Here's how to check it:

Take a piece of sheet/plate stock, and mill one edge straight. Bolt the plate down to the mill table, so it slightly over-hangs the edge. Lay the fat side of the square along the machined edge, with the thin side resting on the plate. Use a scribe, or better yet an X-Acto knife to carefully draw a line in the place, very close along the thin side of the square. Now flip the square over along the milled edge, so the fat side is pointing the opposite direction, and line the edge of the thin side up with the line you just scribed. If the line is not *exactly* parallel to the edge of the square, then your square is not square...

Regards,
Ray L.

[outsider787]

Thanks Ray for the advice. I understand what you mean.
I need to do some checking. I was going to do the Hoss' tramming as per his videos as a first check/adjustment.

I don't know if the vice is/table is perpendicular to the spindle. Need to check.

Also checked the machinist square, and it's square.

The gap at the top is about .035" over the 3" length of the block.

[SCzEngrgGroup]

Ok, so you were surfacing, not milling the edges of the piece? From your description, I thought you were trying to mill two edges perpendicular to each other. If you were surfacing, then your column is not perpendicular to the table surface, and/or the table top surface is not parallel to the ways, so the table rises/falls as it moves. Or, if you were milling the edge, then your head and/or column are not properly trammed. 0.035" over 3" is HUGE!

Regards,
Ray L.

[outsider787]

Followed Hoss' video on tramming a G0704 and trammed the spindle to the column and then the spindle to the table. My BF20 machine was not out of true by very much.

Then I slapped the vice on the table, and did some measurements to it.

WOW is the stationary part of the vice ever out of square! (I can see why my part came out wonky)

What's the best way to fix the vice? Should I just machine/remove enough material off the (removable) face to square it to the spindle?

[rpovey]

Is it not straight, or did you not square it with the table?

[outsider787]

I guess I wasn't very descriptive in my last post.

The stationary vice jaw is parallel to the x travel of the table. That's easily aligned.
I shimmed the vice on one side so that the inside bottom of the vice (the 2 flats that run along/besides the thread) are square to the spindle in both x and y : they are parallel to the table along their length and between the two of them.

But if I clamp a 1-2-3 block to the vice jaws, and move the spindle up and down with a dial indicator along the upright face of the block, I get .015" over 3" of travel. (123 block is clamped with bar on one side to ensure the block is flat against the jaw surface)

So the base of the vice is square to the spindle, but the clamping face of the jaw is not.

So I took it off the jaw (2 bolts), and clamped the 1-2-3 block to the stationary part of the vice (the face that the jaw clamps to), and its out by the same amount.

So should I leave the vice face alone and just machine the jaw so that just the jaw face is square to the spindle? This has the drawback that every other jaw that I make will need to be 'adjusted' in a similar way.

Or should I machine the vice face so that all jaws will fit un-modified?

[photomankc]

What kind of vice is it? The jaws are usually hard.... hard... so if the material behind is machinable then I would try to true that up, not attack the jaws. However, I would confirm that with a square first. Set it on the vice ways and check that rear face. If it's that bad you should be able to get a feeler guage in there easy. I would want to be oh-so-certain that it was really truly out before I started gnawing on it. If the fixed jaw is held by screws from underneath it may be worth taking it apart and looking for any obvious issues under it. Hard to imagine a milling vice being shipped that bad. I'd think you're lucky something hasn't pulled loose from it yet.

[secutordesign]

I guess I wasn't very descriptive in my last post.

The stationary vice jaw is parallel to the x travel of the table. That's easily aligned.
I shimmed the vice on one side so that the inside bottom of the vice (the 2 flats that run along/besides the thread) are square to the spindle in both x and y : they are parallel to the table along their length and between the two of them.

But if I clamp a 1-2-3 block to the vice jaws, and move the spindle up and down with a dial indicator along the upright face of the block, I get .015" over 3" of travel. (123 block is clamped with bar on one side to ensure the block is flat against the jaw surface)

So the base of the vice is square to the spindle, but the clamping face of the jaw is not.

So I took it off the jaw (2 bolts), and clamped the 1-2-3 block to the stationary part of the vice (the face that the jaw clamps to), and its out by the same amount.

So should I leave the vice face alone and just machine the jaw so that just the jaw face is square to the spindle? This has the drawback that every other jaw that I make will need to be 'adjusted' in a similar way.

Or should I machine the vice face so that all jaws will fit un-modified?

Are you moving the quill or mill head for your z measurements? I would check the tram of your head prior to messing with the vice. Also, there can be significant slop in the quill when extending it.