# Keeping The X On A Round Column Mill



## Canuck75 (Nov 13, 2016)

Two years ago I posted a thread on keeping the X on my King PDM30 by fixing the rack to the column, and attaching two tight fitting guide blocks on the head. I was getting .001" repeatability. As a method of checking I set a 1-2-3 block in the vise, edge found the X and Y, set both the DRO and lead screw dials to zero, moved the head, edge found again seeing both the lead screws and DRO rereading zero.

I recently watched a You Tube video by Cuppa Joe (Wrong Fu II) in which he used a linear brg and shaft, plates clamped to the top and bottom of the column (8.5" column C/L to shaft C/L), and replacing the hood with a 3/8" flat plate to anchor the brg relative to the head. As a check of the resulting accuracy, he set  DI against the extended quill and moved the head up and down. His results were impressive to > .001". Moreover, because of the sturdy design, the head doesn't wiggle when being moved.

Today I decided to re-test my mill the same way as Cuppa Joe did and have attached a video to show the results. I know the distance between the guide blocks and the  column C/L vs the distance between the column C/L and the quill C/L is not ideal for control, but it seems to work well enough. Cuppa Joe's mill has a split head casting and two clamping bolts, as mine does, but in his case, it doesn't seem to matter how you retighten the bolts. On mine it does, the top one has to be tightened first. In the video you can see how much the head comes adrift after unclamping and if you don't fully retighten the top bolt first it will be off, as it was in one case in the video. Just the interaction between the rack and the split head as it comes back together I believe.

Anyways, it was a bit of relief to see that the setup is still accurate.

Canuck75


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## mickri (Dec 19, 2016)

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


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## JimDawson (Dec 19, 2016)

The problem with that is the witness marks will get you kinda close, sorta.   You still have to dial in the last few thousandths.  Consider the distance from the column to the spindle, a very small amount relative movement at the column translates into a large movement at the spindle.


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## tq60 (Dec 19, 2016)

Best simple solution we can come up with is a simple post and base plate.

Imagine a chunk of good round stock welded or attached to a flat chunk of steel with one hole in it.

This must be square to table so a machinists square is also needed to verify.

When needed this is bolted to table and verified square to table.

Method to measure distance to spindle depends on your style.

Adjust z then place spindle distance same distance as before and remove tool if needed.

Repeatable to accuracy of tooling and build.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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## mickri (Jan 7, 2017)

Canuck75
I am wondering just how hard it was to attach the rail to the column.  I can chuck the column up in my lathe using my 8" 4 jaw chuck and a 6" center that I have held in the steady rest.  I could then use the carriage with the dial indicator on the compound to keep everything lined up.   But I worry about everything staying line up as I drill the holes by hand.  How did you clamp the rail to the column as you went along.  Do you use large hose clamps?  What were some the problems that you had to overcome to do this?
Chuck


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## mickri (Jan 9, 2017)

I have also been playing around with having a separate round 1 inch column as shown in some of the threads about solving this problem.  One of my concerns is keeping everything in alignment and the rigidity.  I took rough measurements of my drill/mill and 3d modeled it in Google Sketchup.  I then modeled a 1 inch column held fairly close the the head.  Jpeg's of the models are attached.  The head of my drill/mill is wider at the back than the front and there is a 1 inch step in the casting where the width changes.  A bushing would fit nicely in this step.
  IMHO which could be way out in left field I think that one long bushing would be more rigid and easier to align than two bushings spaced several inches apart.  Boring a long bushing will likely have some taper to it resulting in play between the bushing  and the 1 inch column.  My machining background and experience is basically zilch.  But I have a lot of experience working with fiberglass cloth and epoxy or polyester resins.  One thing that I have done in the past when needing a tube to fit tightly to a shaft is to wrap the shaft with fiberglass cloth and resin.  You get a tube that precisely fits the shaft.  You better hope that the shaft is straight and round because if it's not you won't get the tube off the shaft.   Once the tube is made you hold it in place and apply more cloth and resin to mold the tube in place.
To make the inside of the tube harder and less susceptible to wear you can add powdered bronze or aluminum to the resin.
Getting back to my drill/mill I would assemble everything making sure that the 1 inch column is in alignment with the column on the drill/mill and then I would apply more cloth and resin to mold the tube to fit the step in the head casting and have some tabs that you could drill for fasteners to hold the tube in place.  I would end up with a bushing that precisely aligns the head to the 1 inch column.
What do you guys think of this solution to the X axis problem.


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## Canuck75 (Jan 10, 2017)

mickri said:


> Canuck75
> I am wondering just how hard it was to attach the rail to the column.  I can chuck the column up in my lathe using my 8" 4 jaw chuck and a 6" center that I have held in the steady rest.  I could then use the carriage with the dial indicator on the compound to keep everything lined up.   But I worry about everything staying line up as I drill the holes by hand.  How did you clamp the rail to the column as you went along.  Do you use large hose clamps?  What were some the problems that you had to overcome to do this?
> Chuck



mickri,-

What I did was to lay the column on two v-blocks on the mill table with the rack topside by eyeball, then strap clamped the top of the column to the table. This kept it secure and the angle plate holding the DI is on a flat parallel; and smooth surface. Then, as I mentioned in the original thread, I predrilled the rack for the 1/8' roll pins in the drill press (as amany as you want), and drilled the top and bottom for FSHCs. I started by anchoring the bottom of the rack to the column with a FSHC. I then set up the angle plate with the DI attached so the angle plate runs along the side of the column and the DI runs along the side of the rack. The angle plate with the DI attached running against the column is what accurately confirms the alignment of the rack to the column centreline. Make sure the angle plate runs smoothly on whatever flat surface you are using. As I progressed up the column making sure the rack was at zero on the DI, I held the top of the rack to column with a c-clamp, drilled the roll pin hole through the column and drove home the roll pin. Move up to the next roll pin hole, make sure the DI again reads zero(warp the rack a little sideways if not), reclamp the rack at the top, recheck the DI, drill for the roll pin and install. Repeat until you are at the top. If you have done everything correctly the rack is now perfectly parallel to the column centreline and fixed firmly (forgive the use of the small claw hammer - it was just handy). The top SHCS finished the job.

Hope this helps.
Canuck75


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## Canuck75 (Jan 10, 2017)

mickri said:


> I have also been playing around with having a separate round 1 inch column as shown in some of the threads about solving this problem.  One of my concerns is keeping everything in alignment and the rigidity.  I took rough measurements of my drill/mill and 3d modeled it in Google Sketchup.  I then modeled a 1 inch column held fairly close the the head.  Jpeg's of the models are attached.  The head of my drill/mill is wider at the back than the front and there is a 1 inch step in the casting where the width changes.  A bushing would fit nicely in this step.
> IMHO which could be way out in left field I think that one long bushing would be more rigid and easier to align than two bushings spaced several inches apart.  Boring a long bushing will likely have some taper to it resulting in play between the bushing  and the 1 inch column.  My machining background and experience is basically zilch.  But I have a lot of experience working with fiberglass cloth and epoxy or polyester resins.  One thing that I have done in the past when needing a tube to fit tightly to a shaft is to wrap the shaft with fiberglass cloth and resin.  You get a tube that precisely fits the shaft.  You better hope that the shaft is straight and round because if it's not you won't get the tube off the shaft.   Once the tube is made you hold it in place and apply more cloth and resin to mold the tube in place.
> To make the inside of the tube harder and less susceptible to wear you can add powdered bronze or aluminum to the resin.
> Getting back to my drill/mill I would assemble everything making sure that the 1 inch column is in alignment with the column on the drill/mill and then I would apply more cloth and resin to mold the tube to fit the step in the head casting and have some tabs that you could drill for fasteners to hold the tube in place.  I would end up with a bushing that precisely aligns the head to the 1 inch column.
> What do you guys think of this solution to the X axis problem.




mickri,-

I have continued to follow solutions to "keeping the X" and have seen the kind of solution you are suggesting but using a shaft and a linear bearing. All these solutions have merit in one way or another. The arms and linear bearing idea is rigid and accurate once it is lined up. Something to think about is that the "arms" might interfere with the hood or require it to be removed altogether. If they are out to the right they may restrict how high you can raise the head because the idler pulley may run into the top arm. So, lots to consider. I don't know anything about fibreglass but your ideas sound interesting.

Try and view Cuppa Joe's "Wrong Fu 1" and "Wrong Fu 11" videos on You Tube using arms/shaft/linear bearing as a solution.

Hope other H-M members way in on this.

Canuck75


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## mickri (Jan 11, 2017)

I have watched his videos and like how he attached his bushing to the side of the head.  That is what gave me the idea to see if I could attach my bushing to the side of the head on my mill/drill.  In my proposal the upper arm would interfere with the top of the hood.  If my rough dimensions are accurate I would only need to cut a hole in the bottom of the hood for the 1 inch column and remove a small portion of the upper hood piece to clear the upper arm.
I think that your method of attaching the rack to the column is the simplest and most elegant solution if your can keep the rack lined up.  I will be taking the head off of my column this week.  The head does not move smoothly went lowering the head and I think that the gear that meshes with the rack has a broken tooth.

Chuck


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## Canuck75 (Jan 11, 2017)

mickri,-

As I said, lots of things to consider. On mine the control "arm" is from the column C/L to the C/L of the rack or approx 3". This control 'arm" is then attempting to keep the accuracy of the "arm" between the column C/L and the quill C/L of about 8". It would be nice if it was the other way around, the big "arm" controlling the little "arm", but this is not to be in my setup. However, considering it works very well, was cheap, is actually accurate, repeatable, and keeps the esthetics of my machine, it is therefore fine for my purpose and needs.

If you are going to make a better system consider that "arm" question. Keeping your linear bushing close to the head won't give you the control or rigidity during head movement that placing the bushing futher away will. Cuppa Joe uses "arms" about equal length thus very rigid.

Anyways, the fun is in making something of your own design and seeing it work in the end.

Good luck and happy machining!


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## mickri (Jan 12, 2017)

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.


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## Canuck75 (Jan 12, 2017)

mickri said:


> 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.


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## mickri (Jan 12, 2017)

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


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## minsk (May 8, 2022)

mickri said:


> 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...


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## mickri (May 8, 2022)

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.


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## scottdube (Jun 13, 2022)

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!


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## epanzella (Jun 13, 2022)

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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## scottdube (Jun 14, 2022)

epanzella said:


> 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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## mickri (Jun 14, 2022)

Scottdude Have you seen this thread? https://www.hobby-machinist.com/threads/rf-30-clone-head-alignment-guide.84270/  Several members have made these.


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## scottdube (Jun 14, 2022)

mickri said:


> Scottdude Have you seen this thread? https://www.hobby-machinist.com/threads/rf-30-clone-head-alignment-guide.84270/  Several members have made these.


Thanks, that is interesting!


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## epanzella (Jun 15, 2022)

scottdube said:


> 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


Here's some pix. I used a 6 ft piece of 3" x 3" x .500" angle iron attached to the stand to mount the ground rod. The hole the rod goes thru is oversize to allow dialing it in. I used the 4 bolt holes for the old manual crank head lift to mount the bracket that holds the pillow block. I wanted the indexing rod to be as far as possible from the column to minimize runout. When I built the powered head lift I added a piece of angle so I could tie it all together at the top of the column.  Unlock the head, raise it, lower it back, lock the head again, and it repeats to .001inches. When the head is unlocked the tool will be stable but .005" from the locked position. If I'm doing a lot of drilling, tapping chamfering, ect that requires constant raising and lowering of the head I just leave it unlocked. The indexer is rigid enough to handle that on it's own.


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