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Mill/Drill question

10s4me

Aluminum
Joined
May 13, 2006
Location
WA
Hello, I'm new here and have a question about a mill/drill benchtop type mill machine I recently purchased. I bought it from http://www.harborfreight.com the green version. Good machine so far but my only problem I have is when raising or lowering the head (Z) is to loosen two bolts on the side of the machine. Thus creating a swing to the left or right. There's absolutely no way to tell if the head is centered to that of the table. I've looked for some type of marking, number, etc. and I've found nothing. If anyone else owns a mill/drill machine and if yours has something that aligns the head with the table, please let me know. If I start cutting aluminum or something, it's gonna be tapered a bit and possibly scrap the part.
 
I have an older grizzly mill drill, looks almost the same. It does not matter if the head is centered to the middle of the table, it is made so that it will cut accurate anywhere in the swing. Is that what you mean?
If you indicate your part and then raise the head then your in trouble, it will be off.
 
You've just discovered the single biggest shortcoming of the mill/drill. My first machine looked exactly like yours but had a Rutland Tool name plate. It's one of the main things that made me move to a Bridgeport
 
Some people have reported mounting a laser pointer or level such that it points to a line drawn verticaly on the shop wall some distance from the machine, in any direction. As lng as the head is rotated such that the dot is on the line, it will be centered.
 
Excitable Boy, unfortunately, this is my only option since I don't own this place and limited on space. I want a Bridgeport but perhaps in the future.
 
If you don't want this problem but stay in the smaller mill sizes you buy a mill with a dovetailed rectangular column. HF also sells a small knee mill which is covered in a Yahoo group with 9x26 (The table size) in its name.

Moving the head to the left or right will not "taper" the part unless you don't do the bolts up tight when taking a cross cut where the table moves front to back. Most people think the real problem is resetting the head after changing tools.

Chris P
 
I use a laser level when I need to change the height of the table on my drill press, then re-center the spindle.

I used a plumb bob and chalk line to snap a vertical line on the wall about 5' behind the press. You want the line as far away as possible as long as you can easily see the dot. You need to be very careful when you snap the line. If the line is off, you'll have an error that increases the farther you move your table or mill head.

Best of all would be to leave a plumb bob permanently hanging from the ceiling with the bob in a bucket of water to damp (no pun intended, as far as you know) any movement of the bob. This is a bit "retentive," though, and I find that the line is more than enough.

Before I move the table I put the level on it (the level is magnetic) and center the dot on the line. It's not a perfectly round and crisp dot, so a bit of eyeballing is called for. Then I move the table, re-center the dot, and remove the laser from the table. The laser lives on top of the drill press, stuck to the belt guard so that it's always handy.

I have measured this using my Blake Co-Ax indicator, and I can consistently return the table to center within +/- .002". Best of all this procedure is fast, and there is no need to change tooling to insert a wiggler, indicator, etc.

Two thou is pretty good on a drill press but might be a large error if you are boring (well, not you personally....I mean, if you're using a boring head. ;) ) or doing some other precision work, and in that case you might need to use a indicator to perform the final tweaking.

Try it. Works great. Frankly, I think this is about the only good use for the laser levels that just shoot a line. I'd never buy another of those. The only useful laser levels are the ones that rotate or produce a "fan" shaped line. Otherwise you might as well use a water level, it's more accurate and easier to use too.

Glenn
 
bcstractor, money is an issue as well. I can't just go out and buy that red mill you mentioned....however, it was an idea and thought about it too but again, space is limited in a 1 car garage. Since I've had a few responses to my question, I've came up with 2 solutions. First I can try milling something in the X direction with one pass. Then, I'll raise or lower the head and take another pass in the same axis direction. After that, measure the part to see if its within the same measurement at both ends. OR....another idea I came up with is to remove my 4" vise from the table, and dial in one of the 4 t-slots and make it square from there. Then put the vise on the table and dial it in. Then recut the softjaws if necessary since they might not be square with the new loc of the vise.
 
I've had a Jet mill/drill,for about 15yrs.and have used the useless laser pointer that was a gift for aligning my mill head.That function is the only good use for the pointer! I have it attached to the mill by a horseshoe magnet,with the spot on a vertical seam in the drywall 20ft.away.I can raise and lower the head and get it right back in the same spot! I also have a gas strut,as used on car hoods and trunk lids to raise the head of the mill.Instead of two hands,I can use one finger on the crank handle.
 
You can easily measure if the column at the back is square to the table by putting a dial indicator in the spindle and move the head from side to side with the indicator touching the table. In general the column IS square to the table.

The real problem with these machines is getting the head back in the right place left to right if you move it vertically to remove a chuck or for some other reason.

Don't cut the vice jaws. You need to make the jaws parallel or square to the table with a dial indicator.

I think that you need to figure out in your head how the spindle moves in an arc when you move it from side to side. The spindle should not tip at an angle to the top surface of the table. Movement to the left and right and front to back is controlled by the X-Y leadscrews.

Chris P
 








 
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