Author Topic: Increasing Y and Z axis using X2 parts  (Read 2374 times)

Offline superc

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Increasing Y and Z axis using X2 parts
« on: February 26, 2014, 02:45:04 PM »
 :proj:

I have this big old safe near my lathe.  Steel and concrete, over 1,000 lb. hasn't moved a 1/16" inch in 25 years, not even during an earthquake a few years ago.   Somewhere in the process of haggling over back plate designs, communicating off line with other X2 owners and perusing Ebay while epoxy filling my own column an idea began to percolate.

Why not mount an X2 column onto the side of the nearby safe?  Combine it with a sliding table (or a used real mill table).. 

Yes, I am aware the of the gib screw precision issue regarding some sliding tables.  As always, we get what we pay for.  There are $80 dollar tables, and there are $400 dollar tables.  Surely some things are different between the high and the low ends?

Additionally I note that Ebay has several used big mills for sale, some broken and being sold as parts/scrap or for rebuild.  The $2,000 price range, Bridgeport type I knee/column mills, etc.  Last night I saw an ad for a complete table pulled from one of those 40 something inches long.  Sadly that vendor didn't have the parts below that make a table work also for sale or at $400 I would have dusted off my Amex card and acquired it on the spot.

The old 1940s vintage Bridgeport Series Is with the type C wide motor housings used 440 volts to generate a 1/2 horsepower motor which drove the mill head.  My SX2 with 110V generates a full 3/4 horsepower.  The old bridgeports could hit 4,000 RPM, vs the 2500 of the SX2, but with less HP.  So the cutting power of an SX2 milling head in theory more or less equates to that of a WW2 era Bridgeport production mill with a J head (R8).  In my opinion the only reason the Sieg SX2 doesn't show us that because of the flimsy light weight mount.  Given it was designed for home use, IMO there is not a durn thing wrong with that mill head in concept.

I go to speedymetals.com and look at rectangular tubing.  Yes, I have moved a step ahead in the planning.  Not mount the column to the safe, but mount the column to a brace column and then mount that to the safe (picture amended).  I reject aluminum as a choice.  If I pick 3"x4" (3" stand off and 4" to back the column) with a .312" inch wall thickness, 2 feet long this would cost $49 and weigh 25 pounds.  I would epoxy sand fill it of course.  I am envisioning two rack gears mounted flush top to bottom (or 1 1/2 given the length of the X2 column..), and I would expect the spline gear to happily pass over the joint between them.  Currently the X2 mill head goes lower in Z axis than any project I can envision, so my column mount will be a little higher up.

Another brain flash.  Using tubing of the exact same diameter as the column requires that tubing also somehow be trammed or at least mounted as close to perpendicular with the floor as possible.  Too hard.  Much simpler to bounce up to 5" wide tubing mounted more or less perpendicular to the floor.  That also allows thicker walls of up to a half inch, which would really help in vibration fighting (but add weight to the mount).  A 2 foot length is 43 pounds for $55.  Dropping back to a 3/8" wall thickness, the weight is 35 pounds and the cost is $61.  Again I would epoxy/sand fill it. 

You  would have to unbolt the power box and mount it alongside.  No biggie.



This redesign 'mod' does two things for users.  The usable Z axis has increased by at least 50%.  The overhanging design provides the Y axis with a full 5" of increased space.  Greater than the entirety of the original table dimension in Y.  The X axis is dependent on what kind of table we put in there. 

My first thought was the difficulty of tramming the column before welding it in place.  I almost discarded the whole concept.  Then I realized I was still stuck in Sieg's box and a better paradigm existed.  Just mount the column perpendicular to your floor with either a plumb line or an inclinometer or some such toy.

Now since you trashed the old X2 table and have a new larger mill table, don't tram the column, instead tram the new mill table.  This new arrangement gives you a lot more options.  The height of the column is now fixed, this does not mean the height of the table has to be fixed.  You can emulate a knee if you so desire.  The column vibration issues disappeared when you epoxy/sand filled it before mounting it.  You can put your new mill table on a monolithic block that will never vibrate, perhaps something with a 400+ lb old blacksmith's anvil at the core and bolted to the concrete, or you can attach the new table's base to the same steel I beam or 2,000 lb safe you welded the X2 column too.  It is all your choice and there is much room for variation.

Will I do this?  I dunno.  Not this week, but the concept is there.  Maybe someday.