Keeping The X On A Round Column Mill

Canuck75
I hear you on the length of the control arm and that longer is better. After it was pointed out above about the amount of potential error when trying to use a scribed line and witness mark I did a drawing on Google Sketchup to measure how much a small amount of error at the the column escalated to huge errors at the quill. My column is 4" in diameter and my quill center line is 10.5" from the center line of the column so the potential for error at the quill is huge.
Last evening I sold a 16" Walter rotary table I had gotten with my mill/drill (wouldn't fit on my mill/drill) to the owner of a local machine shop and we were talking about ways to solve the X axis problem. In his opinion the best solution would be to use spacers of different heights off the table. There would be a base plate clamped to the table and a top plate with T slots in it to hold the work. Then have spacers of varying thicknesses used to raise the work to the height needed. Drill a hole in each of the four corners of the base plate, top plate and spacers for pins to keep everything aligned and a hole along each side for a flat head machine screw to hold everything together. He also suggested making the spacers in a grid pattern to cut down on the weight of the spacers. He even suggested drilling and taping a hole through the head into the column for a bolt to lock the head to the column. That would be what he would do if he had a mill/drill in his shop. See drawing.
It would be more time consuming to take off the top plate and a spacer to change the bit in the quill but you would not lose the alignment of the work to the quill. Just another possible solution.

spacer table.jpg
 
Canuck75
I hear you on the length of the control arm and that longer is better. After it was pointed out above about the amount of potential error when trying to use a scribed line and witness mark I did a drawing on Google Sketchup to measure how much a small amount of error at the the column escalated to huge errors at the quill. My column is 4" in diameter and my quill center line is 10.5" from the center line of the column so the potential for error at the quill is huge.
Last evening I sold a 16" Walter rotary table I had gotten with my mill/drill (wouldn't fit on my mill/drill) to the owner of a local machine shop and we were talking about ways to solve the X axis problem. In his opinion the best solution would be to use spacers of different heights off the table. There would be a base plate clamped to the table and a top plate with T slots in it to hold the work. Then have spacers of varying thicknesses used to raise the work to the height needed. Drill a hole in each of the four corners of the base plate, top plate and spacers for pins to keep everything aligned and a hole along each side for a flat head machine screw to hold everything together. He also suggested making the spacers in a grid pattern to cut down on the weight of the spacers. He even suggested drilling and taping a hole through the head into the column for a bolt to lock the head to the column. That would be what he would do if he had a mill/drill in his shop. See drawing.
It would be more time consuming to take off the top plate and a spacer to change the bit in the quill but you would not lose the alignment of the work to the quill. Just another possible solution.


mickri,-

If I understand this approach correctly he is advocating keeping the head at the top of the column and bringing the work within range of the quill and tooling with the "spacers". That certainly is different but no matter how much you "lightened' the spacers you would be adding weight to the table (wear), and, keep in mind that the mill is most rigid when the head is at the bottom of that long column and tooling plus quill extension are also kept to the minimum.
 
Canuck75
This is where my lack of experience comes into play. How many spacers you would need would depend on the amount of distance you would need between the work and the quill to be able to change tooling. The space needed to change tooling might be fairly consistent. Although I showed 3 spacers with thicknesses of 1, 2 & 3 inches you might actually only need one of those spacers to be able to change the tooling. The height of the head would not necessarily have to be at the top of the column and could be lower depending on the height of the work. I lack the experience to be able to answer these questions. The shop owner was thinking along the lines of his bridgeport mills when he suggested locking the head in place with a bolt at the top of the column and bringing the work up to the head.
I also don't know how long this whole setup would need to be. Or even if you would need the bottom plate. You could probably drill the holes for the locating pins in the table top and the holes for the screws to lock everything in place could be lined up with the T slots in the table top. A 1 or 2 inch spacer might be all you need. I don't know. Again my lack of experience.
Thanks for your comments and suggestions. When I get my mill/drill setup my first project will be to solve this X axis issue. How I do that remains to be seen.
Chuck
 
I have an Excel EC 30B Mill/drill and have been pondering this round column x y axis issue. I have read numerous threads about possible solutions and all seem to entail a fair amount of precision machining, fabrication and alignment. What I have been thinking about doing is scribing a line down the column parallel to the column axis coupled with a witness mark(s) on the head. When you move the head all you would have to do is realign the witness mark with the scribed line and you should be good to go. This seems like a really simple solution. I am I missing something here?

Chuck
this is what i did on my drill press..i have a 2 axis vise it...so i have to lower and raise the head alot...i centered it perefekly...then put some dykem on the column...and then scribed a line...
 
I have a similar x/y axis vise on one of my drill presses and have worked a little bit to try to get it centered without success so far. But I haven't put much effort into it either.

What I now do on my mill/drill is use a dial indicator in combination rod and a magnetic base. I position the rod and the DI against the head. Then zero the DI. Move the head wherever I need to and then bring the head back to where the head just touches the rod and the DI reads zero.

IMG_3922.JPG
 
I'm going to do this to my round column mill. I'm currently motorizing the lifting/lowering of the head. That has a plate that will let me attach the head to a rail via a linear bearing. I hadn't considered the length of the arm so much before. Great point!
 
On my HF clone I used a 7/8" ground rod with a pillow block as the bearing. It has served me well for a few years now.
 

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On my HF clone I used a 7/8" ground rod with a pillow block as the bearing. It has served me well for a few years now.
That's an interesting take, I'd love to see the whole thing. Is the rail bracket all one piece? What is it mounted to?

Thanks
 
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