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X3/SX3 SMALL MILL

How I increased stock CNCFusion kit travels:
The CNCFusion Deluxe X3 kit is great, but travels are only a little more than what the stock X3 has:
X =15 7/8 inches
Y = 5 3/4 inches
Z = 14 3/4 inches. Spindle will touch table with CNCfusion deluxe kit.

I wanted more.

My expanded travels are:
X = 18 inches (This could be increased to 20 inches)
Y = 8 inches
Z = 18,0 inches. Spindle will STILL touch table.

My enclosure has a 48 x 32" working envelope, and the mill just fits with base mounted off-center to right.

HOW TO MEASURE AXES TRAVELS:
X)
FIRST run the spindle down close to the table, and the Y all the way back. A: Run the table all the way left. Mark the position of center of spindle. B: Run the table all the way to right and do the same. Now measure between marks--that is your X axis travel. 18

Y)
A: Run the saddle all the way back. Measure distance from column to rear side of table. B: Run the saddle all the way forward. Measure the same. Now subtract A from B. That is your Y axis travel. 10-2=8

Z)
  A: Run the head down as low as it will go. Measure distance from spindle to table. B: Run the head UP as high as it will go. Measure the same. This is your Maximum Spindle Height. Now subtract A from B. That is your Z axis travel. If A measurement was Zero, then Z travel and MSH are one and the same. If CNC only moves the quill, then Z Axis travel is maximum quill travel.
18-0=18

Here's what those travels look like:
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At no point do any of the axes extend more than 45% OF THEIR GIB.
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ATTENTION:
 these extensions are over-traveling the gibs a bit. They are for light-duty like cutting long slots or something. You cannot load 150 pounds onto the end of the table  and have any useful extension. You must realize though, that even with
NORMAL travel, some of the gib is exposed. I am only increasing that slightly.

Nothing I've done weakens the table itself, or limits the table load within normal travels. This just gives you the option of say drilling two holes 18 inches apart, or cutting a slot up to 18 inches long. Or being able to drill two holes in the y direction that are 8 inches apart.

The X3 table is rated for 150 pound working weight. That includes any vise, rotary table etc. that you have bolted on there. As long as that stays within normal travels, it's good. Anytime the table or saddle (or both) exceed normal travel, then the weight that the table can hold goes down.

Mostly it's moot though, if you work on parts of less than 20 pounds. Or if you have an equal amount (total table load less than 150 pounds) of weight at each end of the table and centered on the Y axis.

My extensions required a lot of work. You can do yours much more easily than mine if you have not yet purchased a kit. If you are buying a Deluxe kit, Michael at CNCFusion has agreed to Custom cut your ball screws to the CR lengths needed. (NO EXTRA CHARGE!) You will than only have to make the X/Y spacer blocks. This is REALLY an advantage for the Z extension, because you will not have to fabricate a new mount for the lower bearing block.

So, with the custom Z screw length, you will only have to drill a top hole, move the top bearing block, make new mounts for the lower electronics cover screws, and make a filler block for the large open space at top.

With the custom X and Y screws, you will not have to turn any extension spacers. You WILL have to make the X and Y spacer blocks and use longer screws.

The CR Deluxe custom screw lengths are: X= plus 1 5/8 inches, (To expand to 20 inches X would need to be 3 3/8" longer) Y= Plus 1 1/4 inch, Z= Plus 2 1/2 inches. (Or Z could be left stock and still get the increased travel--See end of Z mod)

Okay, here is how I extended my stock CNCFusion deluxe ball screws:

X SCREW:

1. Make a spacer for the X mount:
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This spacer is an inverted "U" 1 1/4 inches thick. I used a 1 1/4 inch block of steel. To make it fit the table, it needs to be
1 1/2 inches high. So the dimensions are 6 3/8" wide, 1 1/2" high, 1 1/4" deep. The U channel starts 1.5" from left side and finishes 1.75" from the right side. the channel is 1/2" deep. It can be made from 6061 aluminum.

http://www.speedymetals.com/pc-2312-8351-1-14-x-1-12-6061-t6511-aluminum-extruded.aspx

This spacer could as easily be made as much as THREE inches wide instead of 1 1/4". That would allow TWENTY inches of X travel, and move the table equally in each direction..

To do this, the X ball screw would have to be 3 3/8" longer, or you would have to make a longer turned spacer.

You will need 1 1/4" longer mounting screws (Or 3" longer mounting screws.) I couldn't find socket-heads that long, so used hex-head and spacer nuts.

And make some extensions for the X screw. Here is the short spacer I made for the handle end of the table.
This allows the end of the screw to penetrate 3/8 inch more into the ball nut:
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On the other end, the screw is just a bit short with the spacer block installed:
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So I made an extension shaft for the Ball screw. This shaft is bored about .002 less than the screw end size. Then the screw is frozen overnight, to shrink it and the extension shaft is heated to cherry red, to expand it. The extension shaft then taps right onto the screw end and when cooled, will never come off, You can see the teeth marks where I held it with Vise grip pliers when it was hot:
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The important part of this extension shaft is the inside bore. The outside is invisible, so I took no pains to make it pretty,
but it does the job nicely: Notice the size of the excellent CNCF helical coupler. It is MASSIVE next to the screw.
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The extension shaft does not actually go INTO the ball nut because it cannot reach it.

We have now extended the X Axis 2 1/4 inches. If you are just ordering your Deluxe kit (This is the only one for which free custom lengths are available) then you can just order the X screw 1 5/8 inches longer. (Or 3 3/8" longer for 20 inch X travel) Then all you have to do is make and install the spacer block and buy some longer mounting screws.

Y SCREW:

My goal here was to equalize the travel front and back of the spindle. So Now my table ends extend equally to the front of the spindle and behind it.

To extend this travel, FRONTWARD we must make the screw longer to allow more forward travel. A turned 3/4 inch spacer on the far end of the Y screw allows the saddle to come farther forward Notice the lock washer under that bolt:
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If I had not installed the washer and bolt, (Which also holds the spacer ON) then the saddle could be driven forward until the balls all fall out of the nut. Future CNCFusion kits will come standard WITH some sort of screw retainer now.

There needs to be a 3/8" spacer on the OTHER end of the screw also. If you have the screws custom cut to CR travel mod size, then you will not NEED any screw spacers.

That was the EASY part. Getting the saddle to move farther BACK is much harder. For this, you must allow the screw to travel farther towards the column. This is accomplished by making a spacer that allows the saddle to move underneath it and approach the column more closely:
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This should be 3/4 inch thick. I used what I had, which was 2 pieces of 5/16" steel. You could use 3/4" aluminum and make it match the top of the mount. The under part is cut out to straddle and slide over the ball nut.

So this spacer will be 4 1/4" wide by 1 1/2" high by 3/4" thick. The inverted "U" part starts 5/8" from left and finishes 3/4" from right side.
The "U" channel is 1 1/16" high. It can be made from 6061 aluminum.
 
http://www.speedymetals.com/pc-2300-8351-34-x-1-12-6061-t6511-aluminum-extruded.aspx

you will need 3/4" longer socket-head screws.

That was the SECOND easiest part. With this done, the saddle at least has the opportunity to move farther back. It can't actually DO so though, because the screw will hit the column. And if we drill a hole to allow the screw end to penetrate the column, then the SADDLE will hit the dovetail way and stop about 1/2 inch short. We must also compensate for the length of the bolt head. So we have to drill a 1 3/8 inch deep hole in the column, AND machine away some of the bottom of the dovetail way.

This is VERY easily accomplished by removing the column and machining it on another mill. Without a mill, you can drill it on a drill press and grind off the lower dovetail way.

DON'T do it as I did--With the column still bolted onto the machine:
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Doing it this way makes a messy looking job--But it WORKS quite nicely and is invisible under the way cover:

If you are ordering a Deluxe kit, tell Michael to make the Y ball screw 1 1/4 inch longer.


Z AXIS:

Remember, I did this the hard way. YOU, even if you go the full bore route, can do it much easier without moving the lower mount, with a custom-length ball screw. BUT, at the end of this, I will show you a much easier way YET, that does not involve moving the cover up, or drilling a hole through the column top--or even a custom-length ball screw.

One way to increase head height from spindle is to make a riser block and mount it between the column and base. This would have to be very accurately machined and trammed perfectly to work properly. This would be an easier mod if you have the equipment and are capable. I felt that a 3 inch riser block might compromise rigidity and I chose instead to increase travel at the top. Later, I decided to add a column brace. WITH the column brace, the three inch riser would have been a lot more attractive, and IT could be machined to take the Y screw into IT--Instead of the column.

One OTHER factor influenced me though. I did NOT want to cut out the back of the case so the Z motor could fit inside, (The way you have to do for the stock CNCF kits) and open up my electronics to possible chip or coolant contamination. This way, that area remains sealed.

Here's the normal Z Axis at its highest elevation---ONLY it ISN'T normal--The Z saddle is elevated an inch FARTHER than
normal. Normally, that saddle would be an inch lower because of hitting the electronics cover. So if we raised the cover one inch, there would be one inch more Z travel--Even if we did NOTHING else.
Now look at that top nut. The back plate hits it and stops any further Z travel. Just imagine if that back plate didn't stop until
it reached the top of the opening? That would increase Z travel at least another 2 inches.
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Of course, then some of the Gib would be exposed, but not an inordinate amount. Thjere are no chips to contaminate the gib at this height. And there is not much side load on that head saddle. So, There is extra height to be had--NOT for precision work, but for simple things like tool changing over a high workpiece etc. This extra Z height is well worthwhile to have--Even worth going through the hell it took ME to achieve it. All YOU have to do is measure from the top of that back plate to the top of the column, then add that measurement to standard Z screw 29 inches when you order your deluxe kit. Michael will cut you a Z ball screw that long and you will just have to drill a hole, mount the top bearing and move the electronics cover up. In my case, Michael would have to make the screw 2.5 inches longer.

Here's how I did it though, and maybe those of you who already HAVE your kit will do it this way also:

1) Determine center of shaft and drill a 5/8 hole through column top. It really helps if you have access to a floor standing drill press for this. After you remove the brass bearing, and BEFORE you install the ball nut--Use the backplate to establish the hole. Just lay the backplate on TOP of the column, line up the sides, and mark
through the backplate hole. Then determine center of that hole and punch a dimple.

2) Drill and tap the mounting holes for the bearing mount. Here, I am tapping mine just a little too close to the edge--You will want these two holes each about 1/4 inch closer to the center. You don't need to drill the 4 small holes around the shaft hole--They were for an earlier bearing design:
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And bolt on the new top bearing mount You can see where I had to cut the washers, because the holes were drilled too far outboard:
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Notice that the mount is tapped for the original bearing block screws:
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Remember: there must be a little end play space in the bearing, so the ball screw can expand and contract.

Now the backplate is free to move all the way up, until it contacts the top of the opening:
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And the bearing block is mounted on top of the column:
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To achieve this happy circumstance, (Unless you are using the custom CR Z screw) you will have to fabricate
a new lower bearing mount that is 2.5 inches higher up the column. This is how I made mine:

Using what I had around, I made 2 pieces of steel fit the column, drilled 4 holes in each side of the column, into the new mount pieces and tapped the mounts to accept 1/4 20 socket head screws ALWAYS wear a mask when drilling or grinding cast iron
It's TOXIC:
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The pulley now falls where the old mount is, so the center of the old mount must be ground out to accomodate
the pulley/belt:
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The face of the mount is tapped to receive the original lower bearing-block screws.
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This is the finished product. Note the angle iron on the sides,  Note also that I have assembled the CNCFusion
Z mount in a new way, so I can mount the motor upside down and keep it out of the electronics bay.
If you are using the custom screws and the original lower mount, you will have no choice but to cut
a hole in the bottom of the electronics case to allow the motor to mount right-side-up. This is a great
improvement over the stock Deluxe kit, which opens up the FRONT of the case and potentially allows
chips to get blown in.
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New bearing-mount screws and angle-iron electronics case mount. Notice how front of case is still sealed:
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So now it will work--but we still have to mount the electronics case and fill the huge opening
at the top.

I chose to cut a piece of 2x6 lumber to size and screw it to the same angle iron that mounted the top bearing. The top case
screws are now wood screws that go right into the 2x6:
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If you have opted to install the column brace, you will have to cut a slot into each side of the electronics
case, so the case can be easily removed later:
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Here's the finished job, just needing a coat of gloss black on top of the primer:
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If YOU are going to do this much extra work, Tell Michael to make the Z ball screw 2 1/2" longer. But there is an EASIER way:

Okay! Was all that Z work scary? Would you LIKE to have the 3 plus inches of extra Z travel WITHOUT having to drill a big hole in the roof? WITHOUT having to make the rear cover stick way up in the air? Well you CAN!

Let's look at that top bearing. Is it really necessary? With the lower end chucked in a lathe, the 29 inch CNCFUSION kit ball screw does not whip until driven upwards of 1200 RPM. (The G540 is not likely to drive it more than 1000 RPM.) That's an unsupported screw. In reality, the ball screw is never supporting less than 1/3 of the screw. So for all practical purposes, the screw will NOT whip if we leave off the top bearing. The BALL NUT actually acts as a supporting bearing. So you can get the ENTIRE 3 1/2" Z travel extension WITH only the standard-length CNCFusion kit ball screw, and with MUCH less work than I did.

You WILL still have to cut a little from top front and each side of the cover though, to let the side plates and saddle raise up, and a loose spacer will have to extend the screw a little so the ball nut does not over extend:


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And of course, if you opt for the column brace, that's another cover cut. But by and large, this is a MUCH easier way to get the extra Z height.

CR.
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