Spindle Alignment

[forrest39]

So I thought all was well with my X2 with the X and Y axis motivated per Hoss's conversion designs when I realized that I can't drill holes where I think they should be. I made one part and the the profile dimensions were perfect. When I drilled a hole, it was .025 off in the x axis. I thought my math was off so I recalculated everything and made another part - exactly the same error. (at least I'm consistent!) After making two blems- I decided I had to figure out what was going on. I discovered that when I center drill a pilot hole with a .25 center drill in a collet then used a .323 drill in a chuck, the centers were not even close. I had trammed the mill with minor adjustment so that told me that the spindle was not aligned and while it was square with the table, the spindle center changed whith z axis movement.
I took the head off and loosened the 4 bolts that bolt the spindle block to the z-slider (I don't know what the correct name is) and after 3 attempts I managed to relocate the spindle so that the error is positive direction not the negative side.
So finally the question -- What is a good method of aligning the spindle so I'm not making swiss cheese any more?!?

Thanks,
-4ist

[mwood3]

one method of squaring the column is to get a long piece of true round stock and put it in a collet, using an indicator on the round stock run the Z axis up and down to "tram" the column in. the longer distance you can measure the better off you will be.

Im sure there are better methods, this is just one that will work and will give you a good indication of how square your cutting bit is running in relationship to the table. Remeber the longer your cutting bit the greater the error will be exagerated, hope that makes sense.

[hoss2006]

read below the tramming section here for links to a few ways to align the head.
http://www.hossmachine.info/Shop_Info.html#tramming
Hoss

[Boots]

The "Machinist" approach is simple. Put a finger indicator (or dial test indicator) in the spindle and bring it down to the table surface and Zero it. Rotate the spindle by hand and sweep it from side to side and front to back making sure it is Zero in all the quadrants every 90 deg. Loosen the bolts that hold the head keeping one slightly tighter than finger tight to piviot on, and tap the head from side to side using a DEAD BLOW HAMMER to tram it in. If it is off from front to back then your mounting plate may need to be either shimmed or milled flat. As you tighten the mounting bolts the head might move so tram and tighten at the same time until every bolt is tight. I would also use tread locker (not the permanent type) on the bolts so they do not come loose from vibration. You will typically need to do this from time to time in the event the tool runs into anything forcing the head out of sq.
Hope this makes sence to you.

[mwood3]

The "Machinist" approach is simple. Put a finger indicator (or dial test indicator) in the spindle and bring it down to the table surface and Zero it. Rotate the spindle by hand and sweep it from side to side and front to back making sure it is Zero in all the quadrants every 90 deg. Loosen the bolts that hold the head keeping one slightly tighter than finger tight to piviot on, and tap the head from side to side using a DEAD BLOW HAMMER to tram it in. If it is off from front to back then your mounting plate may need to be either shimmed or milled flat. As you tighten the mounting bolts the head might move so tram and tighten at the same time until every bolt is tight. I would also use tread locker (not the permanent type) on the bolts so they do not come loose from vibration. You will typically need to do this from time to time in the event the tool runs into anything forcing the head out of sq.
Hope this makes sence to you.

Tramming the head would not solve the problem stated in this thread...

the problem experinced here comes from the colum not being square to the table. It comes into play or becomes noticable when you use drill bits of different length (i.e. center bit then drill bit) The only way to fix this problem is to tram the spindle in square to the table. With column misalignment you actually get Y or X axis travel at the tool bit as the Z axis is traversed. The Op. stated that his holes were off in the X direction so this would indicate the column needing to be tilted one way or the other.

[forrest39]

Thanks for the responses and links. I have a plan to align the spindle once I come up with some 1/2" drill rod and some brass shim stock.

I'm well practiced at tramming the x axis but is there a good procedure for tramming the Y? One I square the spindle in the X and Y, tramming the column in X and Y should solve my issues. I think...

Thanks!
-4ist

[mwood3]

Tramming the Y would involve shimming between the head and mount.

[Boots]

If the head is not Sq. to the table then it is impossible to produce good parts. your sides of the parts wouldn't even be sq. to your part. As you found out holes etc. will be off location also. On a bridgeport, for instance, the head has to be squared up all the time in order to produce quality parts and "Tramming in the head" is the first step in setting it up. This is usually only a problem on the X axis. Once the Y axis is trammed in it usually remains intact on any mill or Router.

[Dano523]

Step one, using a gauge in the spindle, get the column to table trammed (read shim the base to column support the needed direction so the spindal is constant/trammed to on the Y axis).

Next get the head square to the table so it does not change on the Z stroke. Not only may you need to rotate the head left to right, but shim it as well.
Note, there are many ways to check for this, but a fine dot laser makes short work of such in the spindle to verify that the head is set correctly as you move the head up and down on the column.

From there, then you can tram the column to the table (X via the back column nut) if you did not do such in the first step, and if all the above's are trammed as well, no mater where the head is in the Z axis, it's all going to be the same to the table/workpiece as long as your spindle and collet are running true.

Lastly, if you have not installed a back column support brace, now would be a good time for such. Lets face it, the column to base has a lot of flex, and until you resolve that, the slightest bit of pressure will have the tool center all over the map on the work piece.

[forrest39]

I have 1/2" drill rod on order. I plan on using Rollie's Dad's method to align the spindle in the saddle in Y first, then dial in the X. I'll pull the column off to do this. While I'm at it, I may put a piece of channel on the back for column support. I am continuously taking 2 steps forward and 1 back. I can move the table where I want it, but when it comes to making precision holes - I'm making swiss cheese.
After I align the spindle I'll tram the column. Hopefully all will be well then...
Cheers! -4ist

P.S. I don't know who Rollie's Dad is, but I think he should stand up and take a bow!