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Next, holes are drilled and tapped for mounting the column mounting plate as well as holes for mounting the y-axis way extensions. I used 5/16" bolts for the column mount and 10-32 bolts for the way extensions.
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As anyone who has used an X2 minimill knows, y-axis travel is very limited. I converted a minimill to cnc a few years back and have been constantly plagued by the lack of y-axis travel. Push came to shove when I wanted to use it to machine parts for a gantry router I have under construction so I finally decided to do something about it.
On his website, Hoss lists a couple of mods to the y-axis to extend it around .75" in one direction and around 1.5" in the other. Unfortunately, the latter allows the saddle to over travel the ways by an excessive amount. This thread describes how I solved that problem by extending the y-axis ways.
I began by hogging out the throat of the minimill base. This modification encompasses Hoss's modification and the modification which can be found in the Y! minimill group. This modification necessitates relocating the column mount to the back of the mill base. Shown in the first few images are the throat clearance and the initial milling of the flats for the new column mount.
Next, holes are drilled and tapped for mounting the column mounting plate as well as holes for mounting the y-axis way extensions. I used 5/16" bolts for the column mount and 10-32 bolts for the way extensions.
Next, I fabricated the new column mount out of 3/4" mild steel. All holes are drilled and tapped and a test fit is performed on the minimill base.
I skipped a few steps and didn't take any photos during the process but I recut the base where the extensions will mount - mainly to square up the ends of the existing ways. Then I cut the way extension blanks out of 1/2" mild steel and rough fit them to the base assembly.
Next, I cut the 60 degree dovetails in the way extensions. The extensions are left slightly oversized for fine fitting. The material removal here is to take the load off of the dovetail cutter.
Trimmed and ready for installation.
Here's an image of the base just prior to being put back on the table for final installation.
Here I'm using a very clean edge to indicate the base. That edge was cut during the hogging out of the base throat.
Here are the goodies to be installed.
The base is secured to the table and the parts are installed. The way extensions have been secured with 10-32 socket bolts and a very thin film of JB Weld. I let the epoxy cure for 24 hours prior to final machining.
Finally!!!!
The dovetails were cut with a 60 degree dovetail cutter. To bring everything flush, I removed about .015 from the base of the dovetail, .018 from the left hand dovetail and .023 from the right hand dovetail. The top of the ways was surfaced with a flycutter. This was all done in a single set up to ensure everything is parallel and in the same plane.
That's all for now. Next up will be cutting the dovetails in the saddle and X2 table. Then on to lapping and polishing of the ways.
Nice. Looking forward to more updates.
Very cool. How much travel travel will you get on Y?
With no over travel of the ways, I'll get 5.625" of travel. If I over travel toward the stepper mount, I can get a little better than 6". Considering I started with around 3.5" (the chip guards were getting in the way), this represents a HUGE improvement and makes the machine so much more useful. To utilize this increased travel, I'll need to machine a spacer for the spindle to z-axis mount.
I have tons of other mods planned for my X2 while it's in pieces including a counter balance, limit switches, new spindle bearings and some sort of column brace.
Great work! I would probably have had to order a new base for mine if I tried that!
I'm waiting for the Large Table Assembly from LM, http://www.littlemachineshop.com/pro...ory=-269978449
Once I have that in house I might try something like this to extend travel even further, if the larger base allows it.
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