Now I know my X, Y ,Zs

January’s theme seems to be the setup of the RF-45 milling machine. After it got mounted on its stand last weekend it was time to take a closer look at it. I knew that when I had decided to buy a clone there were going to be issues. I considered my purchase of the machine simply as a starting point on the road to getting a useable machine. The assembly of the machine is, in my opinion, terrible. I don’t think the clone I got is any worse then other clones it’s just that you get what you pay for. The most noticeable issue was how poorly the x axis and the y axis move. Some sections of the lead screws were tight and choppy, others loose and chattering. The backlash in the lead screws also seemed to be excessive. I consider the machine unusable out of the crate. I decided to spend some quality time with the machine and get to know it from the inside out.

 Before I continue on with what I really have to say I thought I would give an opportunity for a short 3 minute break. Some visitors to this blog have no idea what a milling machine is, many of you do. If you are one of those that keep scratching their head every time you hear the words milling machine then scratch no further. I have posted a video made by Glacern Machine Tools that is a very basic intro to what a milling machine is capable of doing; it also clears up the whole x,y,z mystery. If you are one of those that know what the equipment is used for then just skip the video and carry on.

 

My main focus was to get the x and y tables to move smooth and precise. I started by removing both the cross feed and the table feed off the base of the machine. The removal process was fairly straight forward and logical with the exception of the tapered pins that center the lead screw end bearing plates. It took a 4mm x .70 screw and a slide hammer to pop them out however once removed the rest came apart easy.

 Once I had the table dissected on the bench some of the main issues became evident. The ways and the lead screws were all lubed using a heavy, thick grease. I have no idea what kind of grease it was that was used but it resembled something close to Silly Putty. Every moving component had this grease on it making it impossible for tight clearances to move smoothly as well as makes fine adjustments of the ways and lead screw nuts impossible. The precision ground ways looked to be in good shape except for the holes where the gib locks were drilled. The bore of the holes that contact the gibs had burrs, once again, making proper gib adjustment impossible.

 I had no idea how backlash was adjusted on the leadscrew nuts until I actually got my eyes on the nuts. The nuts have got a slot cut half way through the nut that runs parallel with the threads of the nut. There is then an Allen head adjustment screw that allows you to vary the pitch of the lead screw nut thereby adjusting the backlash out. Without changing the adjustment of the leadscrew nuts I cleaned the grease from them and the leadscrew. With all components spotless I inspected the factory backlash adjustment of the nuts. Not even close! Granted it was next to impossible to adjust with all the thick grease gooped in the threads.

 Up till this point it was looking like all that was needed to improve the movement of the tables was a good cleaning, lubing, and a few adjustments. That is until I looked at the lubrication points, what I meant to say was the lack of lubrication points. The ways and the leadscrews had no convenient way of regularly lubing the contact points. Some machines come from the factory with one-shot lube systems and others can be retrofitted. One-shot lube is simply a way to lube all the required points of a machine from one central oil pump. If you’re interested in seeing the conversion done on a similar RF-45 clone you can visit the CNC Cookbooks website. I chose not to go to the degree of installing a one-shot system however I was prepared to start drilling and tapping the ways and lead screw nuts for the installation of hydraulic oil fittings.

 So the game plan was this; clean all components, de-burr any rough holes that come into contact with the ways, drill and install oil fittings, and then reassemble and perform adjustments.

A trip to a local industrial parts supplier got me an Ultra Cut Gold Hi-Tungsten and Hi-Molybdenum ¼-28 tap, a heavy duty cobalt 135 degree split point 7/32 drill bit, and a 25 pack of Alemite 8000 psi hydraulic oil fittings. I was unsure just how well the cast iron of the milling machine would drill and tap. Clamping the milling table to the drill press, setting my cutting speed to 340 rpm allowed me to drill through the casting like it was butter. It reinforces, in my mind, just how drastic the difference in quality is when working with good cutting tools. I needed to install a total of 10 fittings, 8 for the ways and 1 in each lead screw nut. All fittings would be accessible with an oiling gun except for the lead screw nuts. I choose to install some 3/16” oil resistance vinyl tubing to the lead screw nuts that have oil fittings with the check balls removed. I then built a remote mounted oil fitting console that will allow me to get oil to the leadscrew nuts. On 2 of the ways the gibs also needed to be drilled to allow the oil to reach the lube points.

 

Drilling and tapping for oil fittings was only half the job. Since both the cross feed and table feed are supported on 2 planes the lube points had to be doubled. I ended up cross drilling into all the holes I had previously drilled. This way both the horizontal and vertical planes for all the ways can be lubed from 1 oil fitting.

 

I used my electric ¼ sheet sander to remove some of the factory paint. I cleaned off all the paint from the x table as well I cleaned the base of the machine just under where the cross feed sits. I prefer a clean metal surface near all the “business ends” of the machine. Since some of the blue paint on the lead screw end plates got chipped upon disassembly I opted to sandblast and paint them Tremclad grey.

 Once all the cleaning and surgery was complete it was time for reassembly. All components were pre-oiled using straight weight 30 motor oil. The assembly started with installing the cross feed and adjusting the gibs. Then the cross feed lead screw nut got bolted in and the backlash adjusted properly. Next came the table feed and gib adjustment along with the backlash adjustment on the table feed lead screw nut. The table feed end plates got installed along with the gear for the power feed.

 

Time for a test drive. Wow! What a difference. The movement of both cranks for the x and y tables were smooth and precise. I ended up just standing and spinning handles for awhile, it felt like butter. I was concerned that I had the gibs adjusted on both tables a bit tight however the movement of the lead screws show no indication of over tightening. Needless to say the machine feels very useable at this point.

 The fix took a week of my time but I would say it was effort well spent. As for what is next, I am still working on setting up the tooling. No chips will be flying just yet. Perhaps I will focus my attention back onto the coolant splash shield while I await my tooling orders to arrive.

Movin’ on up

So I spend the past week planning for this weekends “big lift”. The milling machine stand that I built over the past couple of weeks had 2 coats of Tremclad brushed on and was ready to have the workhorse lifted, and secured, onto its table. For those of you who need a history lesson check out my milling machine stand post Off with their heads! I wasn’t quite sure how the whole deal was going to go down. Some unknowns consisted of; was the engine lift going to reach high enough? Were the lift legs going to be in the way of getting the machine onto the stand? Was I going to be able to sling the 700 lbs machine in a safe a stable manner?

I used a 2 ton engine lift crane to do the moving.  The first issue was that the crane legs are not wide enough to straddle a pallet. I cannot understand why engine lifts aren’t manufactured to be able to get a pallet in between the legs. I have used numerous different lifts over the years and out of all of them only 1, a German made lift, was designed to fit a pallet in between. Anyway…I got the machine somewhat (and I do mean somewhat) balanced and lifted with the crane only to give me enough room to take my circular saw to the pallet. I needed to cut the pallet away so I could reposition the lift to get a better vertical pull on the machine.

I cut a couple lengths of 5/8” hot rolled round bar to slide through the casted holes of the machine base. After slinging, and re-slinging, the base numerous times I finally got a solid hold of the machine to be able to get it into the workshop closer to the stand. Lifting from the base of the machine is kind of scary since the unit is so top heavy. I did not feel comfortable lifting it the 32” required with it slung the way it was.

After numerous more attempts I finally discovered, what I thought be, the best, safest, and most stable set up. I ran a couple straps around where the gearbox mounts to the rear vertical support. It balanced the weight nicely and, would hopefully, allow me enough crane height to get the machine all the way onto the stand.

Next problem I had was that the crane legs would not straddle the machine stand, big surprise! (no…not really) The lifting hook of the crane was not going to reach far enough into the center of the stand table allowing me to place the machine centered on the stand. The only solution I could come up with was to place a floor jack under the crane in order to get more reach. See the picture below, it’s too hard to explain the details.

I would not say the lift went smoothly and it certainly lacked finesse however in the end the machine finally made it atop and sat resting in its new home. I still have all my fingers and toes and the machine suffered no damage so I guess I am happy.

The machine got bolted down to the stand using ½” ready rod at all four corners. I put some rubber sealing washers where the rod goes through the table top splash pan in order to prevent coolant from leaking through the bolt holes and into the frame of the stand.

The wooden stand sides got bolted on and the toolbox slid into place. Finished! At least that part. It’s a relief to have the machine off the floor and out of the way. I can now start with cleaning all the oil and grease from the machine and performing a basic inspection. I suspect the machine will need some attention before it is put into use as the China built machines are not assembled with the greatest of care.

Off with their heads!

 

The RF-45 clone milling machine has been sitting on the garage floor since before Christmas patiently awaiting some support. I, once again, have struggled coming up with a design for the stand and so the game plan turned into more of a game than a plan. There were certain criteria that had to be met. First the stand had to be functional (obviously). What I mean to say is that the factory stand lacks any useable storage space. It is a cabinet that takes up a ton of cubic foot useless storage space. I decided to build in a tool box to allow for tooling storage. Second I wanted a stand that was a few inches higher then the factory one. I am unsure if there is a golden rule surrounding the height a milling machine should stand at. My lathe sits too low and my back aches after extended use of the machine. I wanted to make the machine height more body friendly. Third I wanted to incorporate provisions for a coolant system, which may be added, later down the road. This means coming up with a shield and a drain system. I did a lot of searching to see what others had done in regards to a splash shield. Most of the samples I saw had shields that appeared to be in the way, most of the time; as well they seemed to require some assembly each time they are used. I opted to go with a splash shield that will move vertically on linear bearings. The weight of the shield will be counter acted by a counterweight. The counterweight will be riding in between the upper support columns.  Once the system is built I should be able to effortlessly raise and lower the shield. I had an idea of what I wanted so I started to build “by the seat of my pants”. The blog title got its name from the shape of the stand. Once it is complete I suspect its shape will resemble that of a guillotine.

 

The stand needs to be able to support the 750lbs machine as well as withstand vibrations during machine use. The main structure is built from 2 x 2 x .100 square tubing. Everything was TIG welded and, except for the front face, all the welds were left un-ground to help maintain their strength. The height of the stand reached just over 9 feet. I chose to finish the sides off using some G1S plywood I had kicking around. I typically don’t like to use wood on my projects however my work benches are sheeted with wood so I thought I would keep the theme consistent.

 

To allow for levelling of the stand I chose to add some adjustable feet. Like with most anything I build that needs to sit on the floor I used 6 oz hockey pucks for the feet. I started buying the pucks by the bucket full. The lower frame section got 1” coupler nuts welded on the inside at each corner. The feet were then made from 5” chunks of 1” ready rod with washers welded to them. When I designed the stand I tried to do it in such a way that the welds would not support the weight. Not that I don’t trust my welds I just think it’s a smarter way to build and it allows for more rigidity. The welded washers on the feet breaks my “design rule” and subjects the full weight of the stand and the machine on the welds. Hopefully I was in “the zone” when I welded the feet together. The hockey pucks were drilled out using a 1” drill bit to allow for the ready rod to sit inside. The title picture of this blog post are the shavings from the hockey pucks, I thought they looked cool.

I am not going to spend time describing the linear slide system that will control the splash shield on this post. There will be a separate post dedicated to the design and build. The only thing I will mention is that the rear support columns need to allow for a bearing track on both the outside and inside of the columns. The shield will ride on the outside track and the counterweight will ride on the inside. There will be a cable connecting the two systems together. The cable loops over top of the rear columns. I bought 2 replacement caster wheels for $4 and cut a groove down the center of them to allow for a cable guide. The support columns were plasma cut to allow for caster supports. The outside bearing guide is made from 1” x .250” flat bar while the inside track is constructed from a couple of 5” sections of 3/8” square bar. Since I need the machine mounted on the stand before I can fabricate anymore of the shield system I concentrated my efforts on getting the main stand built.

 

The future coolant system is going to need some way to control, contain, and drain the liquid. I opted to build a tray from 11 gauge steel and incorporate raised sides to help contain the coolant. Since I do not have a bending brake (hmmm…more tools), I was forced to perform the time consuming job of welding, and grinding, the 1” flat bar lips onto the tray ensuring the tray was water proof. I then cut 2 drain holes and welded in a couple of 3” section of 1” steel pipe. This will allow me to thread on a drain attachment at a later date. Since the toolbox does not extend all the way back in the stand it allowed me some clearance for the drains and plumbing.

 

I woke up Saturday morning to the remains of an overnight snow storm. I included a picture of my snow covered gazebo (the roof seems to be holding so far). Since everything, and everybody, was snowed in it gave me a reason to spend the day in the garage (who am I kidding, I don’t need a snow storm to give me a reason). By the end of the weekend I had the main structure fabricated and at paint stage. I plan on spending the week preparing to move the milling machine onto the stand next weekend. If I have time I will try and get some more of the linear slide built.

What’s in the box?

Well Christmas has come and gone and, for me, that usually means new additions to the workshop. After many months of researching a milling machine purchase I finally settled on a RF-45 clone from Machine Tools Warehouse located in Cambridge Ontario (Canada). It was a toss up between the Busy Bee Craftex CT054 knee mill and the RF45 clone.  There was a lot of debating between the 2 and the decision ultimately came down to work envelope size. As nice as a knee mill would have been, the one that was available to be was slightly on the small size.  Now that the money has been spent the machine is sitting in my garage I feel pretty good about the choice.

I opted not to purchase the stand that went with the machine for the sole reason it lacks storage space. In my garage I covet not only my square footage but also my cubic footage. Most milling machine stands have a door with one shelf; I am unsure how anyone can make use of such a poorly designed stand. I realize that a lot of it has to do with economics. For a bit more money I am able to build a stand that will include a lot more functionality. It started with a cheap Craftsman slider drawer  33426 roll cabinet tool box. Then a trip to the metal shop got me 36 feet of 2 x 2 x .100″ square tubing and a 4 x 8 sheet of 11 gauge metal. The plan is to weld up a sturdy stand out of the 2 x 2 steel and build it so that the tool box will fit in the center of it thereby allowing me way more storage space. The cabinet will not hold any of the 750 lbs. worth of machine weight; the steel frame will accept the full load. With the casters left off of the roll cabinet it will allow me to build the height of the cabinet very close to the same dimensions of the factory stand.

A few more work shop additions also included a 220v power feed for the mill. As well I obtained a .500″ R8 keyless DC500 chuck from Glacern Machine Tools for the mill.

 Most of the machining I do does not involve parts that are any more then .003″  accurate. I realize that to many machinists this is probably a sin. The fact is that I obtained the machines to help support my welding projects and welding is not .0001″ accurate. As I spend more time with my lathe I find new interests are emerging and new projects are being stirred up in my head, projects that involve more accuracy. Since the milling machine is now home in my shop the process of outfitting it with all the tooling comes next. I figured it was time to get some micrometers, a test indicator, and a set of machinist squares into the tool box. This is just the beginning and it appears that the difficult decision of which mill to buy was actually the easiest decision. The time consuming job of  researching which  mill vise, end mills, fly cutters, and various other tools I need to obtain will begin. First things first, I will spend the next few weeks getting the stand built and the machine mounted.