Wow. You are an inspiration. I think I took bronze in that event or may have been gold. Seriously tho I've been in such an unusual lazy idk what I'd even call it. I never experienced such lack of wanting to do anything. There is plenty to be done too. You inspired me. Thanks for sharing this play book.
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Supermax vertical mill renovation
- Thread starter Mike G
- Start date
-
- Tags
- bridgeport mill milling
After a lengthy respite to work on another project...
I finally got back to working on the mill when I got to the point, I NEEDED the mill to finish the saw...
I spent a fair amount of time learning about VFD's and trying to figure out what features I wanted and how to set up the control panel. I was trying to design the "perfect" control panel which would provide all my wants/ needs by researching what others had done and found that they ran the gambit from the simplest (mounting the VFD within arms-reach and controlling all functions from the keypad) to panels that rivaled the flight deck of the space shuttle in complexity. I finally decided I had no idea what I wanted/needed since I have never run a mill and rather than waste more time spinning my wheels, I would apply the KISS principle and duplicate the standard FWD/OFF/REV switch that machinists have been using successfully for many decades.
Having decided that, I could finally start actually DOING something. The first order of business was to run a 240V line over to the mill for the VFD and, since I was doing that, I decided to add twelve 120V outlets as there was only one useable one for the entire basement. I added four by the lathe, four by the mill and four more by my workbench, no more using an extension cord for everything, yeah!
Then I wound up taking the upper housing of the head off in order to clean the Bondo out of the tapped holes that were originally used to mount the switch.
Turns out the original hole spacing didn't match the switch, I have no idea how the original switch was mounted, either it was mounted somewhere else or they only used two of the four mounting holes.
The next order of business was to rebuild and repaint the original motor switch so it could be used for the VFD.
Pretty ugly...
I checked the resistance at the screw terminals, and it was 6-10 ohms which was probably too high for low voltage. There was grease, maybe silicone grease, on the contacts which had hardened and coated the contacts enough to make it iffy for use with the 24V control signal.
I ended up taking the guts apart (no picture) in order to clean up the contacts and get the resistance down to 0-0.1 ohms. Then I stripped off the old paint and repainted the housing.
Since I had the motor off, I decided to grease the bearings as there was a little voice in the back of my head saying even though they felt good they still had probably decades old grease in them. Once I got the rotor out, I found that the bearings were double shielded and not double sealed.
I remembered I had a semi-pointed rubber tip for the grease gun and by pressing it HARD against the very thin gap between the shield and inner race, I could pump grease in as long as I went very slowly. I then reassembled the motor and the head, check that one off the list.
I finally got back to working on the mill when I got to the point, I NEEDED the mill to finish the saw...
I spent a fair amount of time learning about VFD's and trying to figure out what features I wanted and how to set up the control panel. I was trying to design the "perfect" control panel which would provide all my wants/ needs by researching what others had done and found that they ran the gambit from the simplest (mounting the VFD within arms-reach and controlling all functions from the keypad) to panels that rivaled the flight deck of the space shuttle in complexity. I finally decided I had no idea what I wanted/needed since I have never run a mill and rather than waste more time spinning my wheels, I would apply the KISS principle and duplicate the standard FWD/OFF/REV switch that machinists have been using successfully for many decades.
Having decided that, I could finally start actually DOING something. The first order of business was to run a 240V line over to the mill for the VFD and, since I was doing that, I decided to add twelve 120V outlets as there was only one useable one for the entire basement. I added four by the lathe, four by the mill and four more by my workbench, no more using an extension cord for everything, yeah!
Then I wound up taking the upper housing of the head off in order to clean the Bondo out of the tapped holes that were originally used to mount the switch.
Turns out the original hole spacing didn't match the switch, I have no idea how the original switch was mounted, either it was mounted somewhere else or they only used two of the four mounting holes.
The next order of business was to rebuild and repaint the original motor switch so it could be used for the VFD.
Pretty ugly...
I checked the resistance at the screw terminals, and it was 6-10 ohms which was probably too high for low voltage. There was grease, maybe silicone grease, on the contacts which had hardened and coated the contacts enough to make it iffy for use with the 24V control signal.
I ended up taking the guts apart (no picture) in order to clean up the contacts and get the resistance down to 0-0.1 ohms. Then I stripped off the old paint and repainted the housing.
Since I had the motor off, I decided to grease the bearings as there was a little voice in the back of my head saying even though they felt good they still had probably decades old grease in them. Once I got the rotor out, I found that the bearings were double shielded and not double sealed.
I remembered I had a semi-pointed rubber tip for the grease gun and by pressing it HARD against the very thin gap between the shield and inner race, I could pump grease in as long as I went very slowly. I then reassembled the motor and the head, check that one off the list.
Attachments
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Next up was installing the VFD. I thought it would have its own on/off switch and I would just need to wire a cord to it but no such luck, so I added a dedicated on off switch after the 240V receptacle. A side benefit is I now have 240 volts available in the basement if I need it.
I then had to add the motor parameters and configure the drive to work off the switch on the mill head. Not as bad as I thought it would be. Then it was time to see if the motor/VFD actually worked. I threw the switch and waited for the smoke...and there wasn't any! Woo Hoo, it's ALIVE!! I still had some adjustments to make that needed the mill to be running, like adjusting the variable speed pulley so that the indicated and actual spindle rpm were the same, or at least as close as they can be. I then had to break-in the spindle bearings for a couple of hours, going from 500-2000 rpm in stages, and let all the new and regreased bearings get acclimated to their newly functional status.
Next, it was time to tram the head and install and align the vise. And finally, the moment I've been waiting for...time to make some chips!
I still have to shorten and route the cables between the mill and VFD but for all practical purposes, it is D-O-N-E done! I plan on adding a DRO and power feed in the not-too-distant future, at least on the X-axis and maybe the others even further down the road.
I then had to add the motor parameters and configure the drive to work off the switch on the mill head. Not as bad as I thought it would be. Then it was time to see if the motor/VFD actually worked. I threw the switch and waited for the smoke...and there wasn't any! Woo Hoo, it's ALIVE!! I still had some adjustments to make that needed the mill to be running, like adjusting the variable speed pulley so that the indicated and actual spindle rpm were the same, or at least as close as they can be. I then had to break-in the spindle bearings for a couple of hours, going from 500-2000 rpm in stages, and let all the new and regreased bearings get acclimated to their newly functional status.
Next, it was time to tram the head and install and align the vise. And finally, the moment I've been waiting for...time to make some chips!
I still have to shorten and route the cables between the mill and VFD but for all practical purposes, it is D-O-N-E done! I plan on adding a DRO and power feed in the not-too-distant future, at least on the X-axis and maybe the others even further down the road.
Just one more mugshot...
...and I'm spent!
Hope you enjoyed the journey, I sure did! Now I have to figure out how to use it and start the most expensive part of the project...the tooling!
...and I'm spent!
Hope you enjoyed the journey, I sure did! Now I have to figure out how to use it and start the most expensive part of the project...the tooling!
Looks great!!
I included a picture at the top of this page of the old Kalamazoo band saw I worked on while pondering the VFD for the mill.
If anyone is interested in seeing the restoration of that saw, it can be found at https://www.garagejournal.com/forum...r-p41-horizontal-band-saw-restoration.543093/
The connection with this project is that I needed the mill to repair the half nut for the saw so that this became my first project with the new mill, and first mill project period since I had never used one before.
They worked perfectly and now the future saw owner(s) will have a spare insert.
If anyone is interested in seeing the restoration of that saw, it can be found at https://www.garagejournal.com/forum...r-p41-horizontal-band-saw-restoration.543093/
The connection with this project is that I needed the mill to repair the half nut for the saw so that this became my first project with the new mill, and first mill project period since I had never used one before.
They worked perfectly and now the future saw owner(s) will have a spare insert.
Mikey, puleeze, you did a full renovation and you're not going to use a Kurt type vise
Well RC4MAN...I hope I qualify now to get my "hack machinist" card back...
Just picked this Kurt D60 up this morning off of FBM. I've been looking for one of these little beauties since I found out I would be getting the "build it yourself mill kit" over a year ago. These things almost never show up around here and when they do, they are pricey! I was actually considering travelling 11 hours round trip to look at one in Pennsylvania at a decent price and then this one showed up 45 minutes away at an even better price. The seller was cleaning out his shop as he sold his seldom used machines a couple years ago and just wanted to make it go away. I was (more than) happy to oblige.
I won't know the true condition until I get it taken apart and cleaned up but looks ok (no beauty contests in our future), works smoothly and tightens up solid. Should be a nice upgrade from my existing vise.
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Once I got the vise disassembled and cleaned all the chips out it was time to evaluate what I had. The first thing to address was the fact that the vise was supposed to open 6" and only opened to 4-1/2". When I bought it, I was pretty sure that it was just chips packed into the front of the nut and that's exactly what it was. I went on Kurt's website and looked up the rebuild kit and it has a plastic plug that was supposed to be in the end of the nut to...wait for it....keep the chips OUT! Huh, imagine that.
The second, and more serious issue was the "condition" of the thrust washer. There is supposed to be a needle bearing thrust washer and some hardened and ground washer/bearing races in between the screw and base which were nowhere to be found, not even remnants. It had been run that way for so long that the thrust faces on the screw and the base were heavily grooved from running against each other.
The centers on the screw were still in good shape so I put it in the lathe and took small face cuts until the surface completely cleaned up, which ended up taking off 0.040" of material
The base wouldn't be so simple as the counterbored surface was in between the two "rails" that the moveable jaw and nut ride on so it was not easily accessible. It would take some interesting fixturing plus either a very long tool or back boring to clean up the surface, neither of which are in my current wheelhouse. I pondered my options, and the first order of business was to determine whether the surface was still parallel to the screw thrust surface. If it wasn't I would have to figure out some fairly involved way to square it up to the screw.
I got all the parts cleaned, tapped holes chased and the important machined surfaces stoned so that I could assemble it enough to be able to install the screw. I did have one broken thrust washer from the original thrust bearing, although it was cracked, which was only 0.030" thick. No way a hardened washer that thin would hold up even if the surface was parallel, so I looked on the McMaster website and found a thrust washer/race that was 1/8" thick that was the same ID/OD as the original for the princely sum of $6. Even if I couldn't use it for the final fix, I could still use it to test the surfaces for parallel. I put a thin layer of Prussian blue on the screw face, put the thrust washer in the counterbore and pushed the moveable jaw back until the screw bottomed against the washer and then gave the jaw face a couple of solid taps with a dead blow hammer.
Huzzah, huzzah! The thrust washer had a nice even layer of bluing on the face, so the surfaces are still parallel, and I don't need to true them up. My plan is to put the washer back in and then tighten the vise tighter than I normally would to smash down any high spots on both thrust faces, especially the one in the base. After that, I can coat the washer with mold release, put a generous layer of JB weld in the grooved thrust face and tighten the vise to just snug until the JB sets up. I don't think the JB Weld is absolutely necessary given the thickness of the washer but it's cheap insurance and I will sleep better knowing it's in there.
The second, and more serious issue was the "condition" of the thrust washer. There is supposed to be a needle bearing thrust washer and some hardened and ground washer/bearing races in between the screw and base which were nowhere to be found, not even remnants. It had been run that way for so long that the thrust faces on the screw and the base were heavily grooved from running against each other.
The centers on the screw were still in good shape so I put it in the lathe and took small face cuts until the surface completely cleaned up, which ended up taking off 0.040" of material
The base wouldn't be so simple as the counterbored surface was in between the two "rails" that the moveable jaw and nut ride on so it was not easily accessible. It would take some interesting fixturing plus either a very long tool or back boring to clean up the surface, neither of which are in my current wheelhouse. I pondered my options, and the first order of business was to determine whether the surface was still parallel to the screw thrust surface. If it wasn't I would have to figure out some fairly involved way to square it up to the screw.
I got all the parts cleaned, tapped holes chased and the important machined surfaces stoned so that I could assemble it enough to be able to install the screw. I did have one broken thrust washer from the original thrust bearing, although it was cracked, which was only 0.030" thick. No way a hardened washer that thin would hold up even if the surface was parallel, so I looked on the McMaster website and found a thrust washer/race that was 1/8" thick that was the same ID/OD as the original for the princely sum of $6. Even if I couldn't use it for the final fix, I could still use it to test the surfaces for parallel. I put a thin layer of Prussian blue on the screw face, put the thrust washer in the counterbore and pushed the moveable jaw back until the screw bottomed against the washer and then gave the jaw face a couple of solid taps with a dead blow hammer.
Huzzah, huzzah! The thrust washer had a nice even layer of bluing on the face, so the surfaces are still parallel, and I don't need to true them up. My plan is to put the washer back in and then tighten the vise tighter than I normally would to smash down any high spots on both thrust faces, especially the one in the base. After that, I can coat the washer with mold release, put a generous layer of JB weld in the grooved thrust face and tighten the vise to just snug until the JB sets up. I don't think the JB Weld is absolutely necessary given the thickness of the washer but it's cheap insurance and I will sleep better knowing it's in there.
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There were also a couple of divots in the top of the base "rails", one of which would need some attention.
The bottom one in the picture is shallow so didn't need any attention, but the other was fairly deep. I started cleaning the chips and "gunk" out and it just kept getting deeper! By the time I hit bottom it was 1-1/4" deep and tapped 5/16-24, what? Sure would like to hear why somebody felt they needed to do that.
I cut the end off a bolt, put a screw slot in the top with a hacksaw and installed it just below flush. Not pretty but it's an improvement and it will keep the chips out.
I ordered the rebuild kit which includes the plastic plug for the nut, the thrust bearing with races and the "half ball" that is the heart of Kurt's much revered and copied AngLock system, and pretty clever in my opinion. The kit was only $17 with free shipping but there is a $25 minimum order so I got a spare thrust bearing assembly. I also called Kurt customer service and talked to the engineering manager, Steve, about getting a parts list for a D60 as there isn't one on their site. Have to say he was a super nice guy, very knowledgeable and VERY helpful in looking up drawings for all my "what fits" and what's available questions. P.S. even though they don't sell the D60 nuts anymore he confirmed that a D675 nut will work with minor modification. He even mentioned that he has kept some/most of the taps for the older vises like mine if somebody needs to chase the threads in the nut and they send them out on a loaner basis...now THAT'S customer service.
The bottom one in the picture is shallow so didn't need any attention, but the other was fairly deep. I started cleaning the chips and "gunk" out and it just kept getting deeper! By the time I hit bottom it was 1-1/4" deep and tapped 5/16-24, what? Sure would like to hear why somebody felt they needed to do that.
I cut the end off a bolt, put a screw slot in the top with a hacksaw and installed it just below flush. Not pretty but it's an improvement and it will keep the chips out.
I ordered the rebuild kit which includes the plastic plug for the nut, the thrust bearing with races and the "half ball" that is the heart of Kurt's much revered and copied AngLock system, and pretty clever in my opinion. The kit was only $17 with free shipping but there is a $25 minimum order so I got a spare thrust bearing assembly. I also called Kurt customer service and talked to the engineering manager, Steve, about getting a parts list for a D60 as there isn't one on their site. Have to say he was a super nice guy, very knowledgeable and VERY helpful in looking up drawings for all my "what fits" and what's available questions. P.S. even though they don't sell the D60 nuts anymore he confirmed that a D675 nut will work with minor modification. He even mentioned that he has kept some/most of the taps for the older vises like mine if somebody needs to chase the threads in the nut and they send them out on a loaner basis...now THAT'S customer service.
It occurred to me that I checked the contact between the thrust washer and the screw but never to the base. I blued it up and checked and it was contacting most of the way around the OD, but only in a narrow band. Based on that, I think the JB weld should help the washer support the thrust load without flexing, so I feel even better about having it in there. I cleaned the thrust bearing area of the base with acetone and coated the washer with a thin layer of grease, so it's possible to remove in the future if necessary and set the washer into the JB in the base and clamped things up snug but not overly tight.
After it sat for a day, I pulled everything apart, cleaned up a little excess JB and...
It looks pretty good. Now I just need the rebuild kit from Kurt so I can assemble it, hopefully for the last time.
After it sat for a day, I pulled everything apart, cleaned up a little excess JB and...
It looks pretty good. Now I just need the rebuild kit from Kurt so I can assemble it, hopefully for the last time.
Since I have to waits for parts anyway, I decided to add a little chip protection to the thrust bearing. The later model vises have an O-ring that fits around the thrust collar on the shaft and, fairly snug, in the counterbore for the thrust bearing. Mine isn't set up that way but I figured I could approximate it by adding a groove to the OD of the thrust collar for an O-ring. I went through my box of O-rings and found one that looked like it could be made to work. I cut the groove 0.020" deep on the lathe but that was too tight in the base and added a lot of drag to the screw. I'm not trying to get it to seal just act like a shield and keep the chips from migrating into the thrust bearing, so I took another 0.010 out of the groove and the O-ring slips in with no drag now.
Hope it helps but it definitely won't hurt and just cost a little time and a couple pennies for the O-ring.
Hope it helps but it definitely won't hurt and just cost a little time and a couple pennies for the O-ring.
My parts showed up yesterday from Kurt. It seems they have standardized on the 1/8" thick thrust washer for their rebuild kits, the same thickness I found at McMaster, rather than the one original 0.030" washer I had as an example under the threaded collar on the vise screw. After assembling everything, the O-ring I added would sometimes pop out of the groove when turning the screw quickly using a speed wrench, so I deepened the groove another 0.015" and now it stays in and looks like it should do a good job keeping the crud out of the thrust washer.
After assembling and anchoring the vise on the mill table it was time to see if my repairs would hold up under load on the thrust washer. I found several manuals online and the max. torque they showed in the torque vs clamping load table was 80 ft-lb, so that was my starting target. I tightened the vise as tight as I could get it using the handle and putting all my weight on it and then checked it using a torque wrench set to 80 ft-lb. It moved ever so slightly before clicking. I then set the wrench to 90 ft-lb and tightened until it clicked again and there were no cracking sounds or crunching and it still felt smooth. Seems they are good to go, now it just remains to see if they will hold up over time, which I'm reasonably certain they will after passing the "proof test". The only downside to the repairs is that the max. opening is now 5-7/8" rather than a full 6" due to the thick washers so it won't hold true 6" wide stock. I can increase it 0.090" by substituting a thin washer for the thick one on the screw, but it still won't open 6" without machining 1/32 off the back of the nut. I doubt it will ever be an issue but if it is, I can always make the changes or use the less capable original vise as it opens 6-3/4".
The first job for it will be making a tool to form the sheet metal blade brush holders for the band saw.
After assembling and anchoring the vise on the mill table it was time to see if my repairs would hold up under load on the thrust washer. I found several manuals online and the max. torque they showed in the torque vs clamping load table was 80 ft-lb, so that was my starting target. I tightened the vise as tight as I could get it using the handle and putting all my weight on it and then checked it using a torque wrench set to 80 ft-lb. It moved ever so slightly before clicking. I then set the wrench to 90 ft-lb and tightened until it clicked again and there were no cracking sounds or crunching and it still felt smooth. Seems they are good to go, now it just remains to see if they will hold up over time, which I'm reasonably certain they will after passing the "proof test". The only downside to the repairs is that the max. opening is now 5-7/8" rather than a full 6" due to the thick washers so it won't hold true 6" wide stock. I can increase it 0.090" by substituting a thin washer for the thick one on the screw, but it still won't open 6" without machining 1/32 off the back of the nut. I doubt it will ever be an issue but if it is, I can always make the changes or use the less capable original vise as it opens 6-3/4".
The first job for it will be making a tool to form the sheet metal blade brush holders for the band saw.
