[mduckett]

I ordered some of this bellows material from McMaster and was pleased with it....

McMaster-Carr

Item #
1320K34

It's a woven nylon material that's slightly stiff. If collapses well (better than the stock rubber) and is a decent replacement. You can cut it with scissors but it's held up fine on my X2.

That being said... I'd want a better sealed environment on a CNC machine if possible.

I'll be interested in what you come up with.

Have you given much thought to the coolant systems? Mist, flood etc? (Edit: LOL, never mind... went back to page 1 of the thread and said 'Doh! Flood it is... )

Thanks for the link and info, options are good. Yes flood, although my machinist friend thinks that mist is a good option. These new anti-flog mist systems are interesting. I've already built up the flood tank/pump/plumbing system and will post that soon. I plan to use Syn-Cool or Kool Mist 77 as the coolant.

[BAMCNC.COM]

Kool Mist works great for Aluminum just mix it twice as strong for flood.

[hoss2006]

I've been using Syn-Kool for years, great stuff for flood.
I also keep a squirt bottle handy mixed 10:1 for little jobs.
Hoss

[mduckett]

Kool Mist works great for Aluminum just mix it twice as strong for flood.

I've been using Syn-Kool for years, great stuff for flood.
I also keep a squirt bottle handy mixed 10:1 for little jobs.
Hoss

Thanks guys, can't wait to be set up to try them out.

[mduckett]

I completed the spindle/column tramming procedure over the weekend. The procedure is basically as outlined here: Mini-Mill Spindle-Column Alignment - Home Model Engine Machinist. I used a ½” turned, ground, and polished 1045 steel rod from Speedy Metals for the test shaft, held in a collet.
Early on I had already tested the Y direction and found the alignment to be around .001” so I knew I only needed to concentrate on the X. After two tries, I got the alignment in X to be about .0015” at 7”, and measured < .0005” at the collet. It was zero initially, but the removing and tightening the bolts always caused it to move, so this will have to do for now. Re-checked the Y direction and found it to be between .001” and .0015” as expected.
I really don’t like that it requires a disassembly of the spindle from the column to do this alignment, so adding a spacer block to allow easier removal of the spindle block from the carriage will be added to the future improvements list. This would also make it easier to access/service the Z ball nut because the current design needs to remove the spindle block in order to allow the Z ball nut carrier to be removed.
Also got started on finishing the limit switch installations and making the column side support braces. I'll post those soon.

[mduckett]

As mentioned earlier, the Z axis ball screw had the .1250” balls replaced with .1256” balls and is good to go. I bought extra .1256” balls and replaced the original .1254” balls in the X-axis ball nut with similar good results. Moving to the Y-axis ball nut, I was disappointed to find that it was very loose feeling with the .1256” balls. Next I tried a set of .1257” balls and found them to also be loose. Puzzled, I pulled out the original set of balls (I counted and bagged all of the original balls in a zip top baggy with a piece of paper identifying the ball diameters and number. I had assumed that this ball nut had the same .1254” balls as the X-axis). Got out the micrometer and started measuring and found these balls were .1258”. So much for making assumptions. I went to Tool Supply and checked for .1259” balls and they didn’t have any, so either try .1260”, which were in stock, or just go with the originals. Since the originals were oversized from RBS, I decided to just stay with those. I measured the back lash to be about .0015” or so, so maybe these are good enough. If not, it’s not that bad to disassemble and replace them later.

[mduckett]

The limit switch mounts for the Y-axis needed to be completed, and the X-axis limit switch needed the actuator stops to be made. Finally, each switch needed to have the Plexiglas covers made.
The X-axis switch housing was previously installed onto the saddle as described earlier. The actuator stops are mounted to the front table slot. I considered several different options and decided on a simple implementation using a bolt and a home made nut that would serve as the stop. The nut is made from ¾” aluminum hex bar. I cut a piece about 3” long, which allowed for 2 @ 1” long nuts with enough left to chuck in the lathe 3-jaw (the bar doesn’t fit through the spindle so a little is wasted). The piece was chucked in, faced, then center drilled then tap drilled for ¼”-20 threads to match the hex head bolts I picked to fit in to the table slot. It turns out that this size will fit into the slot and the hex flats are large enough to engage the slot and prevent spinning when threading on a nut. The hex stock was then threaded with a tap held in the tailstock chuck and hand turning the chuck. I tapped to the depth of the tap, then proceeded to part the stock at .8”. I then faced the end of the bar and repeated the tapping and parting to make the second nut. Each nut was then re-chucked and the parted side faced as it wasn’t perfectly flat (I’m not the best at parting operations). After cleaning up the edges with a file and running a countersink by hand on each threaded hole to clean burrs, the new stop nuts were threaded onto the bolts. Each stop nut was then fitted and the bolts cut to allow them to be flush with the end of the nuts.
The Plexiglas cover was also made and drilled for the X-axis. In hindsight, I realize that I should not have put the cover over the mounting screws, as the cover now has to be removed to mount/dismount the switch—Duh! (Edit: What I meant here is the design should have allowed the cover to be independent of the bolts that attach the housing.) It will work until I make the new housing designs using CNC. As this description is going long, I’ll post the Y-axis switch mountings in a separate posting.

[mduckett]

The Y-axis switches will be mounted as described earlier, one in the front, one in the rear. Both turned out to be more work than anticipated (as usual). The rear mount was complicated because the webs in the column support are skewed both vertically and horizontally so a simple bolt-on solution would not work without significant shimming to align the plunger axis to the saddle. I decided to mount the switch on a L-bracket that would be captured by the center bolt of the column support. Looking around the scrap bin I found a piece of bent sheet metal, probably 20 or 22 gauge (stiff) and even painted blue. Got it cut barely with tin snips, located the holes for the switch and drilled them (2@ #4-40 clearance). The column support was removed from the base, the bracket held in the desired position, and a transfer punch used to mark the hole location. To drill the hole, I put the bracket over a piece of wood and clamped it in the vise on the drill press and worked up to the final holes size. The bracket was lightly filed and straightened using a hammer and small anvil. The switch cover was then cut from Plexiglas and the needed holes drilled (2 @ #4-40 clearance), and the switch was attached to the bracket with #4-40 hex bolts and using nuts and washers. For this switch the cover ended up against the bracket, but no big deal as it will be under the way cover anyway and nothing to see. I couldn’t mount on the other side because the center bolt is not symmetrically located.
The front switch is mounted to the side of the bearing block, however the lower mounting hole landed on a place on the block that could not support a tapped hole (obviously not well planned here). Finally decided to make a mounting bracket that is mounted to the bearing block in a better position, and the switch then held using bolts into tapped holes in the bracket. The bracket is made from 1/8” flat aluminum and attached to the bearing block with #4-40 hex bolts. The holes for the switch were marked using a transfer punch, drilled and tapped for #4-40. Finally everything was bolted on and looks good. The last remaining task is to drill the hole for the cable entries into each switch. I left this for last so I could put the holes in the best places to help with cable routing.

[mduckett]

As described earlier, the two column braces would be fabricated from a piece of 2” x 6” x ¼” rectangular steel tubing. You can buy uneven leg 6" angle iron also, but I had access to some scrap tubing so I wanted to try this approach. To get started, the column was mounted to the base, and the tubing was cut to length to fit the base and column width, which ended up being about 3 ½”. After cutting to length, the tube was sawn through one layer on one side near the end, then turned around, flipped over and sawn through on the other end to make the two L-shaped braces. The short legs were cut to fit the width of the base areas when positioned against the column. This needs to be done individually as the column spacing is a bit variable, so cut them to fit. Cutting pieces like this is awkward on my bandsaw, but I’ve found that using some wood extenders on each side of the piece can help out a lot. I put the piece in standing upright with the short leg parallel to the blade. A scrap piece of ¾” x 1 ½” x 6” on each side, and the second brace acting as a spacer behind. Cut one and trade positions. Once cut, the pieces were belt sanded and filed to get rid of the burrs and sharp edges. In hindsight, I should have milled the tubing flat on all sides before cutting the braces, but didn’t realize how non-flat the sides were. No big deal, just takes more sanding. This is alwo welded tubing, so one brace has the weld evident near the center, but it seems ok excpet for cosmetics. Early on I had planned on cutting the braces into triangular shaped gussets, but after looking at the fit up there was no need to cut them. The pictures how the fit up to the column. I marked and drilled the 5 holes in the braces with the ¼”-20 tap drill (#7) and then used a transfer punch to mark the base and column locations. These were drilled and tapped, and the brace holes enlarged for generous clearance (used a #K drill to open them up). The base holes were tapped to about 5/8” depth as I am using ¾” button head bolts for all. I It would be nice if the base were a bit longer to give more support to the bottom of the braces. If necessary, the whole mill could be mounted on a base plate and a rear base extension could be added if it seems to be a problem. With the braces attached and snugged, the column seems pretty stiff, but I haven’t put an indicator on it yet. It is going to be interesting to see if the braces tend to pull the column out of tram when tightening them down. I plan to tram using shims as required for the Y-direction, and snugging the big pivot nut for the initial tram. Then the braces, which have generous clearance holes, will be tightened up, hopefully without stressing the column. I will monitor the indicator while tightening and hopefully can balance out the stresses, we’ll see. I couldn’t resist doing a quick throw-together once the column was attached, shown in the last pix.

[mduckett]

Ok, so I couldn’t let the Y-axis go without trying some .1260” balls in the Y-axis. I ordered them and they arrived just after Christmas. Finally got around to trying them and they fit very nicely. The nut turns smoothly with no noticeable play, so the Y-axis is good to go.
Other activity has been slow but steady. All of the electronics connections from the breakout board to the external connectors have been completed inside the electronics housing. Also, the X, Y, Z stepper cables were re-wired using the heavier cabling with the oil resistant sheathing. The wire sheath turned out to be too thick for the connectors to fit over, so I stripped the sheath back about 1.5" for the connection, and put shrink tube over that section, then after soldering the connections,the connector body strain relief clamped down on the heat shrink area, and then I put a larger heat shrink tube over the entire assembly and pulled it up over the back of the connector. This makes for a nice sealed connection, at least aft of the connecting nut. An O-ring installed inside the connecting thread ring would make it pretty much water tight. I’ll need to check into finding one that fits, or making some. The motors were all wired with their connectors. I don't know if it matters, but I twisted the wires from each phase (A+,A- and B+,B-) with the theory that at any given moment one of these is tied to ground through the electronics, and thereby providing some shielding--I'm not completely sure if this has any value but if nothing else it does tidy up the wires. The plan is to attach these connectors to the sides of the motor covers. Also made up the X, Y, Z limit switch cable. This was made from some salvaged 9-wire shielded serial cable, the lighter colored cable in the pictures. I’m using 4 conductors in the cable (X, Y, Z limits + common ground). Somewhere on the mill there will be a connection box where the X, Y, Z limit switch connections fan out to their respective switches. I’ll make a separate post later on the limit switch connections with more details. The last connector on the box is a dedicated connector for the E-Stop switch connection. Here I used two conductors and two connector pins for E-Switch and two for ground to add redundancy to the connections.
Getting ready for final assembly, with way covers, motor covers, and the motor electronics box mount left to do. Those things can be addressed after the machine is assembled, so I’m going to proceed with the build up and do those things later.

[SwampDonkey]

Amazing work! I especially like the way you were able to mount the Z axis ball screw down the center of the head. Brilliant stuff. Any chance you would have any of the plans for that laying around? I really need something like this since my CNC fusion mount flexes like crazy.
Thanks.

[mduckett]

Amazing work! I especially like the way you were able to mount the Z axis ball screw down the center of the head. Brilliant stuff. Any chance you would have any of the plans for that laying around? I really need something like this since my CNC fusion mount flexes like crazy.
Thanks.

Thanks for the kind words and the vote of confidence in this design--We'll soon see how well it actually works; you may not want to copy it If it does turn out to work well I do want to put some effort into designing this part so that it would generally fit all mills, but at present there aren't any drawings. I did the 3D model to verify the concept, but for now it's just a one-off custom part that fits one particular spindle carriage. Thanks again for reading.

[mduckett]

Slow/steady progress, working down the final to-do list items. It's finally time to start the build-up of the machine on the bench. The old table/saddle were unbolted and removed with some effort--looks a little forlorn sitting there on my table saw. I found that the ring of silicon I put around each mounting hole did a good job sealing and gluing the base down. Had to drive a single edge razor blade under each corner to get it loose. With the old pieces off and the mounting area cleaned up, the new base was bolted down again using silicon around each bolt hole. The column was then bolted on. Next the Z-axis ball screw was installed into the spindle carriage, and the spindle assembly placed onto the column. This was a little tricky to put on because I couldn’t use the column stop bracket to support the assembly anymore because it interferes with the ball screw. I needed something to hold up the carriage while I worked to get the gib into place, so I used a couple of adjustable F-style wood clamps with the rubber protectors, one on each side of the column about 10” down the column. The assembly was slipped on carefully, and slid down to rest on the clamps, and the gib strip installed and tightened. Next, the column insert block was bolted in place. Next, the end of the ball screw was fed through the Z bearing block bearings and the ball screw turned to allow the block to rest on the column insert. Two jam nuts were used to fix the screw end to the bearings. I had to use some vise grips with a brass strip to hold the screw while I tightened the first jam nut, holding it in an unused area of the screw (how does everyone else do this? -- it never occurred to me to grind flats to hold the ball screw when tightening/loosening these nuts.) Next I tried to insert the three hold-down bolts for the Z-bearing block and found that they would not engage their tapped holes(!). After some wiggling around, the center bolt started, and I found that, for whatever reason, there was a small misalignment that requires about .010” shimming at the rear of the block. Once shimmed, all screws went in normally. At this point I wanted to adjust the gib so I got my cordless drill and chucked on the end of the screw, and to my relief found that the drill easily drove the spindle block up and down the column, even at super slow speeds. The drill was removed and the drive pulley installed onto the end shaft. I found that I could easily move the column up and down with my hand torque, so I felt pretty good that the 381 oz-in motor with 2:1 belt reduction would be able to move it without issue. At one point the pulley began slipping and I re-tightened it, this time really cinching it down. I don’t have a flat on the shaft, so if it breaks loose again I will need to grind a flat. I did quite a bit of hand cranking up and down to locate any tight spots and played some more with the shimming. I also realized that I probably hadn’t applied enough grease to the ball screw/nut so I really gave it a good layer, which improved the smoothness.
With the column installed, the Y-axis was next. With the base bolted down, the only option for installing the Y ball screw is to put the screw through the front hole, then roll the ball nut assembly onto the screw inside the base. This is very easy to do using the tube end adapter I made and described earlier. The saddle is then placed onto the base with the right (gib) side tilted up, then the saddle is slid to the right, aligning and then lowering the saddle slot over the ball nut holder. The single set screw for the holder is then just barely tightened to hold the ball nut in place so that it can be adjusted for alignment and smooth operation. The front bearing block assembly was then put in place and the screw end passed through the bearing. The vise grips and brass were used again to help in tightening the jam nuts, and I attached the inner half Oldham coupling to the screw end to assist in hand turning the screw. The ball screw/nut and bearing were moved around until everything was aligned and moving smoothly, then tightened down. I then removed the coupling and used the drill to drive the saddle back and forth and adjusted the gib. I tried to hold the drill trigger at the same position, very slow, to listen for the motor to drag down, which would indicate a tight spot. With a little more adjusting, everything was running smooth from end to end. I went ahead and installed the Z and Y axis motors and called it a day. Starting to look like a milling machine again!
I decided that this would be a good place to stop and get the limit switches wired for the X and Y axes so that I could test the Y axis (and Z) drives before assembling the X-axis. I also wanted to get the spindle motor installed so that I could test the Z motor with the full load installed, which means getting the backpack electronics mounted too.

[mduckett]

I wanted to maintain the rear mounting position for the spindle electronics box, but with the Z-stepper motor installed, this requires the box to be lower than the original mounting position, but still high enough to be clear of the table. Since the C-channel column stiffener is now bolted to the column, obviously the box can’t be bolted directly to the column, however, there are now plenty of attachment points available with the numerous ¼-20 bolts used to attach the C-channel to the column. I also want to be able to dismount the electronics box without needing to open the box and unbolt the circuit board as was previously required. The idea is for the brackets to be hidden as much as possible and for the box to fit flush against the column. I ended up with top and bottom brackets, with each consisting of two parts; a column attachment piece and a box attachment piece. The two are bolted together using tapped holes in the box brackets and 1/4-20 screws. The column brackets were cut to length and the attachment holes located and drilled for the nearest column bolts. It turned out that a single bolt was available on the top, and two on the bottom. The holes were then turned into slots by cutting down to the hole sides with the band saw. This allows the brackets to be slid into position by loosening the column bolts. With the column brackets installed, the box bracket pieces were cut to size and then positioned against the column brackets to locate the bolt positions. The holes were drilled in each piece, with the column side opened up for clearance and slotted to allow for adjustment. The box-side pieces corresponding holes were tapped ¼-20. New mounting holes were drilled in the box because the original holes were located at the very edge of the column and would not engage the new bracket. With complete top and bottom brackets attached to the column, the electronics box was centered and the box holes marked onto the box brackets. These were then drilled/tapped for the original screws, which are 4mm x .70mm. Two more tapped holes were needed to provide the machine grounding lugs. These originally passed through a slot in the box and were attached to the column. By luck, the bottom aluminum bracket falls right over the slot so the two more holes drilled and tapped and the connections were made to the bracket. I checked the continuity for safety and found good connection to the ground lug on the power plug. The pictures hopefully explain all of this better than the text, but each bracket ends up shaped like a square S. A final step would be to cut the slotted column side pieces down enough to allow removal of the electronics box without needing to completely remove any bolts, but I'm lazy so I will need to remove the top bracket bolt to remove the box--good enough for me. With the electronics box re-mounted, it was time to re-install the spindle control box to the side of the spindle housing and then re-install the drive belt, spindle pulley cover, motor mount plate, and the spindle motor. When completed, I plugged it in, and after months of sitting as a pile of parts, the spindle is once again operational!

[BAMCNC.COM]

Keep up the good work

[mduckett]

The goal for the limit switch wiring was to have a connection point where the single cable carrying the X,Y,Z limit switch signals from the electronics enclosure fans out the cabling to the X, Y, and Z switch locations. I want to be able to disconnect the main cable in case the cable needs maintenance or additional connections need to be added (the cable has 9 conductors, so adding a connector with more pins would be an easy expansion). Shopping around I found a telephone jack breakout box that consists of a small plastic box with a phone jack installed, and inside has a terminal block with a four wire breakout from the phone jack connector—perfect! I made a mounting plate from some scrap ¼” x 2” aluminum flat and tapped a couple of #4-40 screws to match the mounting holes of the terminal block. There was a column bolt available, located just above the big pivot bolt and below the electronics box inside the C-channel that looked like a good place to mount the box. I counter-bored a hole in the plate (the scrap already had a slot cut in it) and bolted it to the column, then attached the terminal block with #4-40 screws. I needed to install a telephone plug on the main cable coming from the electronics enclosure that plugs into the breakout box. I found an old modem phone cable in my electronics junk box, cut off the end, and installed it onto the main cable. A multi-meter was used to ohm out all connections from the cable’s connector pins to the breakout terminals—all good. One note here: not all patch cables have all 4 wires connected to the plug, some only have only 2 contacts actually wired to the plug.
Next was to install the cables into each switch box. I removed the switch housings from the mill and drilled holes in each to pass in the cable with a snug fit, stripped the wires and soldered them to the switch terminals. Since my cable has 9 wires, for redundancy I used a pair of wires for each of the incoming/outgoing connections. I paired red/green to represent the incoming signal and the gray/black pair to be the return signal on all switches. Though it doesn’t matter for the connection, I always used the same switch contacts for the incoming and outgoing connections. (Edit:That sounds good but that's not what the pictures show--Oops) For the Y switches the lower, pivot end contact is connected to the red/green pair, and the other to the gray/black pair. For the X switches, since they are co-located, the red/green enters the box and connects to the bottom contact on the left switch. The upper contact on this switch is connected to the adjacent upper contact of the right switch, and then the gray/black connects to the lower contact on the right switch. I mixed up some 5 minute epoxy and put a bead of epoxy around the cable entry points inside the switch housings to make a seal and to provide some strain relief. Then, back out to the garage to install the switches on the machine and make the connections to the breakout box.
Four holes were drilled into the breakout box cover and the limit switch cables were slid through the cover prior to making the connections. I may turn these into slots if it becomes a hassle to work with this arrangement, but it seems ok. For the Y axis, the red/green pair from the front switch is connected to the breakout terminal with the incoming cable Y limit switch connection. The gray/black pair from the front switch is twisted with the red/green of the back Y switch and the connection soldered and taped. The gray/black of the back switch is then connected to the common return breakout terminal, which is used by all axes. This puts the Y switches into series. The X switch red/green connects to the main incoming X signal breakout terminal, and the gray/black goes to the common terminal. The co-located X switches are wired in series as described above. When the Z switches are installed, they will be wired similar to the Y switches, using the incoming Z limit switch breakout and the common return. I also connected the cable shield to the switch mounting screws, effectively connecting them to earth ground when the machine is plugged in. I’m not sure if this is proper, but would like to use the shielding if possible.
In the picture I show the cables and a coiled phone cord that I plan to install in the final assembly to serve as the strain relief mechanism for the X-axis switch cable as it moves with the Y-axis. At some point I will splice in a short section of the coil near the rear, and use a strain relieving wire to act as a push/pull for the X switch cable, connected to the coiled cord so that as the Y axis moves back and forth, the coil will stretch and retract without straining the rest of the cable that connects to the switch. (Maybe I can find a black or blue cord though) As I’ve seen others do, I plan to route all cables through clear vinyl tubing to provide protection against swarf and flood/oil.

[mduckett]

The day finally arrived to do some computer controlled motion on the machine. The Y-axis was first. I thought that the default settings on the drivers would give me 0.9 Amps and no micro-stepping, so on the first try at motor tuning in Mach 3 the motor was moving very slowly. After playing around for a while, I noticed that the default micro-stepping is not defined, so I configured the stepper driver for half steps and 2.1 Amps, thinking that maybe it was a power issue. Wow—the acceleration and velocity settings were still high from the previous runs and the motor took off like crazy—luckily it was not near the end, though in theory the limit switch would have stopped it. Apparently the default setting is for maximum micro-stepping. After playing for a bit, I found that the Y is pretty good at about 100 inches/min with the acceleration set at 1.5. I’m not sure what settings I should use—I did notice that playing with higher accelerations and velocities there are spots where the motor sticks/squeals so I backed well away from those. The Mach manual just says to find a “comfortable” place, so I’ll start slow and work upward, I don’t care about high speed, at least not right now. Next, up was the Z-axis. I must admit I was pretty nervous here. During my checkouts, prior to hooking up the electronics, I was hand cranking the Z axis to make sure everything was good and out of the blue the Z gib strip just slipped right out! No kidding. After all the running up/down I did to this point. I still had the clamps installed as stops on the column, so at least it could not have slid down past the end of the ball screw, but it didn’t move at all and I re-inserted the gib and adjusted the screws. Turns out I had somehow missed the indents with the screws, but the gib is now firmly locked in. Whew! Hooking up the electronics and using the motor tuning, the Z motor easily lifts/lowers the spindle assembly, which is fully loaded with the spindle motor and hardware. I know it’s been done many times over, but seeing that drive train work as designed is still really satisfying. I’m using full steps on the Z drive to get the same theoretical .0005” resolution as the X,Y direct drives that use half steps. With the Z and Y working well, I proceeded to mount the X-axis ball screw/holder into the saddle and tightened the two holding set screws just enough to hold the screw in place. The X bearing block was installed onto the screw end using double jam nuts. After greasing the screw and oiling the ways, the table was slid onto the saddle. It took some wiggling around to get the end to slide into the non-drive end bushing, but it finally went in and the bearing block was bolted to the table. The inner Oldham connector was installed on the shaft end and I began the gib and ball screw adjustment/alignment. This is tedious as the X axis has 12” of travel. I didn't use the drill this time because it kind of marked up the end of the Y-screw when I used it there, and it's probably good that I didn't. At about 4” to go in the travel I hit a place where I couldn’t turn the screw, it felt kind of spongy but would not continue. I loosened up the screws on the bearing block and the ball screw holder and things started moving again, so I re-tightened in the new position and was able to reach the end. On returning, I again encountered binding at the same place and had to loosen again. About then I realized that I had not loosened the block with the bushing at the opposite end, and that might be causing some mis-alignment. I decided to unbolt the bearing block and slide the table off to examine it and the ball nut carrier. The carrier had a scuff on the top, but I wasn’t sure if it was a new mark or not, and there weren’t any marks evident on the underside of the table. Re-assembled again, this time loosening all bolts and running it back and forth I found a place that minimized the tight spot, but it still seems to persist, but it’s very slight. I decided to press on and see what the drive thought of it, since my wrist was about to fall off from cranking the table back and forth. I also put more oil on the ways and table for good measure. Connecting everything up, I set up the Mach motor tuning for the X with the same settings as the Y axis, it all seems fine, driving the table back and forth smoothly. I need to learn how to post videos so I can show the dynamics of the system; I’ll work on that this week. In the meantime, here are some pictures of the nearly completed system. The picture with the cable is for a reference back to an earlier post when I mentioned about using an O-ring with the motor cable connectors. I bought an O-ring assortment at Harbor Freight and found that the 7.8 mm x 1.9mm O-ring will stretch over the back into the lock ring and makes a nice seal when tightened down. I didn’t try to fit one to the front side yet, but there should be one in the kit that will work there also.

[mduckett]

Spent a couple hours this evening working to tram the column and adjusting the column support brackets. The side-to-side tilt is straightforward and I had no problem getting that within .0005”, however I always have trouble with the fore/aft tramming. I always mis-interpret the direction the column needs to tilt and spend a lot of time trying to figure out why the error is worse AFTER the adjustment. I need to start off with saying that the initial error was about .0025”, not terrible but enough that I wanted to correct it. Long story short, whereas the original base needed a front shim of about .0015” (few layers of foil), the new base needs a rear shim of about .002”. This brought it to between .0005” and .001”, the digital dial indicator would hop between the two, needless to say I quickly cinched it down and called it good. The side to side moved a little out to about .0015” I guess from the shims but I left it, at least for now. The column support bracket bolt holes had clearance, but still were a little too tight and binding a little, so I remove them and opened them up some more. On re-installing, I pushed them up to the column and tightened the base bolts first, then the column bolts, all the while watching the dial indicator. The top bolts had no effect, however the lower bolt did tend to bias the column about .001” in the wrong direction so I just left those snug but not cinched down. As hoped, the column brackets do add a pretty good amount of stiffness. I pushed/pulled on the unbraced column, maybe 5-8 lbs. and saw .002" - .004" deflections. With the brackets installed this was .0005" to maybe .0015", pretty noticeable difference.
Got around to re-designing the X limit switch housing to a more practical design. This was prompted by the upcoming way cover for the front Y axis. The current switch housing is too tall and interferes with the travel and also the way cover that I want to make. Here’s a sketch of the new housing that has the bolts outside the covered area, and the overall height minimized. This will be one of the first CNC projects along with the Z-axis limit switch housings, coming up soon. Next up on the todo list, way covers and motor covers.

[BAMCNC.COM]

Buy or make a "protram" can't get any easier than that.

[SCzEngrgGroup]

Buy or make a "protram" can't get any easier than that.

Below are the drawings for the ProTram knock-off I built about 18 months back

Regards,
Ray L.