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View Full Version : cheap vervsion of aligment help for mill drill



Luke55
03-06-2015, 03:51 PM
After reading nice article from Dave Sage HSM march April. Here is my cheap solution. I hot glue a dollar store lazer pointer on the side of the head. In front of the cabinet 8 ft apart from the mill I suspended a plumb bulb. I replace the string with a .185th strip of aluminum . Same width as the red dot. Assuming the machine is level. Standing at almost the same place on the side of the mill, it is repeatable to less than.001 Not bad for a dollar

TGTool
03-06-2015, 07:01 PM
Have you checked level then to be sure your assumptions are correct? The basic idea is sound and you can't beat the price.

oldtiffie
03-07-2015, 08:29 AM
This is a good idea - covered previously.

It should be noted that it is for realigning the milling head by swinging it around the round column - which it will do very well.

It is not and should not be confused with "tramming" tools.

Sage5902
06-23-2015, 07:39 PM
>> Assuming the machine is level.

Yes. Assuming the machine is level is a dangerous assumption. If the column in not vertical i.e the whole machine is tilted forward or back even slightly then the laser will not be moving vertically as you crank the head up and down the column and will therefore not follow the vertical line on the wall in any case. In that case if you rotate the head to re-align the laser with the line you would actually be mis-aligning the head even if it was travelling straight up and down the column. Getting the machine level to the point that you can trust extending the planes accurately far off the machine IMHO would be difficult. (I'm not sure if the vertical error would be amplified by distance as well).
As pointed out here (and in the article) key number one is a properly trammed machine. A machine can be perfectly trammed but that doesn't make it level.
There are all sorts of other possible problems with mill drills and the way they are constructed that I did not point out in the article due to space constraints.
Simple put it's the old adage "you can't make a silk purse out of a sows ear".
One of note is. What makes you think that the Chinese were capable of machining the hole through the head (that fits around the column) straight through in the first place. Next to nill I'd say. So it's quite likely the quill is not parallel to the column in some direction in the first place and there's nothing that you can do to correct it. It can't even be trammed. Even if it was bored properly the fact that you are tightening that hole around the column is possibly mis-aligning it.
I continue to use my mill drill with my modification and it works well. But it will never be a proper knee mill.

Dave Sage

Doozer
06-23-2015, 11:51 PM
Believe it or not,
the Chinese can make wonderful precision things,
It is just that the importers tell them to make low
grade cheap tools, because that is what sells in
the market and makes the most profit.
Expensive and precision tools have a very small
market compared to cheap, and poor quality tools.
-Doozer

Sage5902
10-12-2015, 10:32 AM
What you say about the Chinese products may be true. But all we see here - for the most part - is the junk so that's what we have to deal with.

Sage

1-800miner
10-12-2015, 10:52 AM
What you say about the Chinese products may be true. But all we see here - for the most part - is the junk so that's what we have to deal with.

Sage

Old adage: You get what you pay for.
You want a Chinese lathe with Monarch quality? They will happily build it for the Monarch price.

Mike Amick
10-12-2015, 01:19 PM
I always liked the laser idea. My take ... the mill should be trammed in a traditional way to get it as close
to tram and you can.

Then a laser should be "indexed" to the machine so that it's position can be accurately replicated.

Then mark where the laser hits on a wall as far away as practical.

So as long as the machine doesn't move, this has to be fairly accurate I would think.

TGTool
10-12-2015, 02:45 PM
Just a minute. The OP is talking about a mill/drill. It has no provision for tramming in a "traditional way" since the head can not be rotated in either tilt or nod. The only movement is the rotation of the head around the vertical column. If it was square with the table on both X-Z and Y-Z planes it will still be square no matter where it's rotated. If one wants to check for correct geometry you can do the usual indicator in the spindle test against the table to keep it honest but if there's any discrepancy the only means of correction is to shim between the column and the base.

So, to get back to the laser alignment. This is a perfectly valid method in principle, PROVIDED that the fundamental geometric error possibilities are accounted for. So, you could mount a laser on the head throwing a vertical line on an adjacent wall. Mount your plumb bob on the wall, adjust the laser line to be perfectly parallel to the line and epoxy it there. Now, as you swing the head around the column the laser line will always be parallel to a plumb line. Can you now just crank the head up and down, rotate it again to have the laser line be coincident with the plumb line and be confident in your re-positioning? Imagine if the machine is tilted at 10 degrees on the workbench. (Yeah, I know you'd never see one like that but it's easier to visualize) With the head at the top of the column you turn on the laser, assure yourself that it's matched to the plumb line on the wall which will not move. Now lower the head six inches and rotate it to again be exactly coincident with the plumb. Is it now in the same position over the workpiece on the table?

Get out the trig. As the head is sliding down the hypotenuse of the triangle for six inches it is moving sideways by Sin(10)*6 or about 1.042 inches. If you now rotate the head to again align with the plumb line you'll be that far displaced from the work.

So what's the solution? One would be to align the laser exactly with the column, even it it's tilted. Then you draw a line on the wall exactly parallel to the column. Now, as you move the head up and down the laser line will always track the column and if you're realigned with the wall line after the move you'll still be exactly right. The two difficulties with this are 1) how you align the laser with the column to start with, and 2) if you've got a line on the wall you always have to have the head in the same position relative to the table. In other words, if you were to swing the head to one side or the other to access a long workpiece, your laser line will now be parallel to, but not coincident with the line on the wall. You'd have to scribe another parallel line on the wall to accommodate the new head position.

The other method is to level the machine up so you can use earth's gravity as a reference. If the machine is square the the world you can mount the laser to the head and align IT to a plumb line anywhere. Now fixed to the head, you can rotate the head anywhere you wish, hang the plumb line to the current head position, move it up and down as you like and when it's swiveled again to plumb it will also be aligned with the table.

Paul Alciatore
10-12-2015, 08:08 PM
The round column, import mill/drills CAN be trammed. You must first remove all the putty that is filling in the junction of the base with the column. Then you need to find which way it needs to go and how much. You CAREFULLY loosen the bolts holding the column to the base and insert shims under the corners, by the bolts, one pair at a time: left, right, front, or back. Torque the bolts back down and recheck the tram. Repeat as needed until it is square to the table.

Of course, you probably want to insure that the table is parallel to the ways first.

As for using a laser to set the rotational position of the head on the column, I favor using a first surface, high quality mirror that is tall enough to cover the entire vertical range of head movement. This mirror can be fixed on a wall and the laser can be aimed at it, in an approximate horizontal path, from any position of the head around the column.

To avoid changing the figure of the mirror, I would make a frame for it and suspend it by one point at it's top center. And with this method, you do not have to have the laser beam dead horizontal. It would be adjusted to be reflected back to a target on the mill's head which could be an inch or so above or below the laser. The mirror doubles the length of the optical path so the method is twice as sensitive to errors. And the laser's spot is at the mill's head where it can be observed easily, instead of being across the room. This also increases the accuracy of the method.

old mart
10-13-2015, 07:51 AM
Great food for thought, our museum drill mill would be easier to use and only needs to have the column vertical from side to side to work. I shall be examining the walls and seeing if obstructions can be circumvented. Also, a mirror on the wall might be the way to go. I use a laser alignment tool to check my car wheels alignment, it works very well.

TGTool
10-13-2015, 02:21 PM
Paul,

I'm struggling with the geometry of the laser and mirror you're proposing. Doubling the length of the light path is a good plan, and it sounds like you're using a spot laser rather than a vertical line. Is that true? And in connection with the mirror and swinging the head, doesn't that mean that the reflected spot is now moving at a double angle if the head is rotated? If I've got that right it means that each time one swivels the head the mirror needs to be rotated and possibly repositioned to bring the spot back on target at the mill. And then if the mirror twitches at any point the reflection is no longer reliable for position.

vpt
10-14-2015, 07:50 AM
Could the laser be mounted int eh spindle projecting on a horizontal plane and spun to create a circular line around the entire shop which can be checked if level/trammed all the way around? Assuming the table is level? Could the table be checked with the same level sitting on a turntable spinning in the same fashion as the spindle? The have two lasers spinning, one on the table and one in the spindle, measure the distance the two lasers are projecting on the walls all around and make it equal = trammed?

TGTool
10-14-2015, 12:14 PM
Yes, that's valid if the turntable can be verified to have its rotating spindle exactly perpendicular with the base and the base is flat to the table. Having the extended distances would exaggerate any discrepancy and make it easier to measure.

In real life it's probably easier to use an indicator in the spindle checking against the table top.

Sage5902
10-15-2015, 10:14 AM
Or. You can forget all the smoke and mirrors and do as the article suggests and install the bar on the machine. No worries about lasers, mirrors, plumb lines, machine being level, vertical lines, angled lines, wall distance trig etc. etc.

Works fine here for me to within a couple of thou top to bottom.

Sage

old mart
10-15-2015, 05:08 PM
I stuck a cheap plastic spirit level with a laser pointing out of the long axis onto the right side in line with the Y axis. On a window about 12 feet away, I stuck a piece of paper, set the mill as square as possible and marked a vertical line to coincide with the dot. I had great success although the job I was working on had +_0.006" tolerance. I have an optical alignment tool and I will devise a test method to find if 0.001" can be achieved.

Sage5902
10-15-2015, 05:37 PM
Don't fool yourself. If the mill is sitting on a non-level table tilted slightly left or right, the dot wouldn't follow a perfectly vertical line on the wall even if the mill head was moving perfectly up and down the column.
There isn't much point spending time trying to get the mill properly aligned with it's environment (the room). That just complicates the issue.
If you intend to crank the head up and down and produce a cock-eyed line on the wall to correspond to the existing angle of the machine - how do you ensure that the head isn't moving improperly as you go through that exercise?

The solution to the problem needs to be machine-centric not environment-centric.


Sage

old mart
10-16-2015, 10:58 AM
Our mill is vertical using a woodworking spirit level, we don't have anything better. I will use a large angle plate and parallels with the optical sight to calibrate the laser target to the mill. I have just bought a cheap laser gun sight on ebay, this has a noticeably smaller spot than the level that is on the mill at present. Allowing the quill movement plus another 10 inches will probably be plenty for me.

KenShmid
10-16-2015, 11:58 PM
The following video tutorials show an interesting way to brace a mill/drill column using a radial bearing, guide rod and some fabricated standoffs:

RF-31 Guide Rail--Part 1 (https://www.youtube.com/watch?v=ddy0T_nbYKk)

RF-31 Guide Rail--Part 2 (https://www.youtube.com/watch?v=BHGnGJZkG3E)

wmgeorge
10-17-2015, 08:41 AM
I had a round column mill years ago and my solution then was the same as now. Get your machine leveled and squared with the table and the mill head lined up where you want it, and use flat head machine screws in counter sunk tapped holes and mount the rack to the column. I even posted online the procedure and pictures. It worked wonderfully. Lots of people did the same thing, this might of been maybe 10 -15 years ago.

Yes its a little more involved than mounting a laser and some mirrors, marks or whatever.

I used it all the time and if its repeatability you want, you got it. I even converted the machine over to CNC.

And its been published by someone else, but I don't recall seeing this before I did mine.

Posted from another website>
The article is in the May/June 1998 issue of The Home Shop Machinist.
The basics are get the rack square to the table. Use flat head socket head screws top and bottom and two roll pins in between on the rack. He states there is clearance between the head and the rack but it is always taken up in the same direction. Claims accurate to .002 in 5".

Paul Alciatore
10-17-2015, 02:23 PM
TG, Yes, I had a spot laser in mind as was used in the first post above. If you are going to use a laser that produces a vertical line, then you are at the mercy of just how vertical that line is. In my suggestion the spot beam travels out and back on a near horizontal line but, as I suggested, a slight deviation up or down would make it easier to do. That deviation would make no difference.

The problem that I see with the original post is that his vertical line on the wall must be parallel to the column of the mill in order for it to work. This could be done, but it is not trivial. And what tolerance on that alignment? And how will it hold under shop conditions? The OP claimed 0.001" accuracy. How did he measure that?

The first thing about my suggestion is that it replaces the need for aligning the vertical line to the mill with the need for a really flat mirror. You can not just go to the local glass company and buy one. You need an optical quality mirror. So it is not going to be a $1 solution.

Oh, the mirror does not change the horizontal angle of the beam so, in that sense, there is no double angle. And the mirror must not be re-positioned at all. It must remain in exactly the same orientation throughout the session. If you rotate the mirror in the horizontal plane you will change the angle and throw the whole thing off. If you are talking about re-positioning the head to one side or the other to reach another part of the table, then you would re-aim the laser to hit the mirror and the target on the mill. This assumes that the mirror has a certain width so it can be hit from all rotational positions of the head.

Yes, if the mirror moves, then the alignment is off. That is why I suggested a frame around it. I also suggested that it be suspended from it's top edge, preferably at a single point, so it is not warped. You want the top and the bottom of the mirror at exactly the same angle.

I know that many here will consider this more than is necessary. Perhaps that is so for them. I have worked with a round column mill and I know what I would want. That would be well under a thousandth, not one or a few.




Paul,

I'm struggling with the geometry of the laser and mirror you're proposing. Doubling the length of the light path is a good plan, and it sounds like you're using a spot laser rather than a vertical line. Is that true? And in connection with the mirror and swinging the head, doesn't that mean that the reflected spot is now moving at a double angle if the head is rotated? If I've got that right it means that each time one swivels the head the mirror needs to be rotated and possibly repositioned to bring the spot back on target at the mill. And then if the mirror twitches at any point the reflection is no longer reliable for position.

Paul Alciatore
10-17-2015, 02:37 PM
A thought just struck me. I was thinking about how to keep the quill of my drill press on the center line when I move the table up and down. This is not an accuracy thing in my mind, just a way of keeping the drill over the central hole so I do not drill into the table.

I think I am going to use the OP's suggestion for that purpose. Perhaps attach the laser to the head pointing down and let it hit a line on the table (existing line?). I would want it to be visible while I am at the rear where I tighten the table clamp. That would be well worth the $1 price, even on my bench top cheapie DP.

old mart
10-17-2015, 04:13 PM
Its not quite as easy as I thought, I have fixed the laser in such a way as to have a 110 feet sight line, something not many others would be able to achieve. At that distance the spot is about 3/4" dia. I clamped a 1-2-3 block at right angles to the X axis and lined the optical sight with the edge, not the chamfer, of the block. The rings of the sight are 0.25mm apart at 20x magnification, it's easy to repeat within 10 microns. Then I raised the mill head 10 inches, set an angle plate against the block, clamped it and attached the other block of the pair to the top of the angle plate. I realigned the sight and the laser spot was no longer directly above the first position. Lining up the spot directly above the original position displaced the head one full ring, 0.25mm or nearly 10 thou. I will have to check the angle plate for burrs, also whether the quill travel is a factor. Locking the quill while looking through the optical sight amazingly does not displace the spindle. I think that the best I can achieve will involve an error chart for a number of mill head and quill positions.

old mart
10-17-2015, 04:26 PM
Our drill press is floor standing with rectangular base and table. Just a glance down past the table will check that the sides of the table are parallel with the base, and as long as the head is central, you are unlikely to hit the table.

old mart
10-18-2015, 02:59 PM
I have just realised why my results with the laser were so underwhelming. I thought a long sight line was an advantage, and so it would have been if I hadn't set the laser tangentially to the rotational axis of the column. The most sensitive alignment is parallel to the radius between the column and spindle. That way, I have about 12 feet to a target on a window, but I could shine through and get about 40 feet (the window is in an internal partition).

TGTool
10-18-2015, 04:53 PM
I have just realised why my results with the laser were so underwhelming. I thought a long sight line was an advantage, and so it would have been if I hadn't set the laser tangentially to the rotational axis of the column. The most sensitive alignment is parallel to the radius between the column and spindle. That way, I have about 12 feet to a target on a window, but I could shine through and get about 40 feet (the window is in an internal partition).

Good deal. It sounds like you're on exactly the right track. Opening a window to let more light in (or out in this instance) is almost always a step in the right direction.