What format do you want them in? It was designed in Solidworks.
I use fushion. I believe if you send them as .sldasm I can open.
D-Flo,
I may have more questions coming your way my friendā¦ I just hit go on a 833TV. Yikes! I figured Iād constantly wonder if I should have bought the larger mill if i went for the 728.
For now I plan on milling the parts for the conversion manually. I figure it would be a neat learning process. As discussed above, I do have a cnc router that can cut aluminum if i find itās required. That being said, it is currently apart as I am upgrading that as well using the mill. I see no way this can go sideways.
Wish me luck.
Craig
Hey guys! Finishing up my enclosureā¦I tell ya thatās been the most labor intensive part. But I believe itāll be worth it to keep the chips from getting all over the shop. Got to get the lexan installed, proxes mounted and x/y steppers wired then to the learning linuxcnc part. I initially started down that road but backed off to get this leg complete.
Well done 
That is by far one of the best looking and most functional enclosures that I have ever seen for a bench top mill. I love how the entire front will swing open.
You guys have inspired me to get my butt into gear and start upgrading my mill.
I got my hands on some AC servo motors, stainless helical couplers, and double ball nut screws.
Iām looking to do some small production runs, so Iām chasing thousandths now. I would love to be able flip the part and have a nice transition (no offset) on the side walls.
I upgraded to a big boy vise, so that should solve a lot of my problems. The moveable jaw on my PM vise went up and down like a roller coaster as I locked my parts in.
I need your help on a couple things whenever you get a chance.
1.) I want to sort out that spindle heat problem. Itās ruining my tools. Do you have a link to that correct oil seal?
2.) I have over a hundred hours on the mill, and I was thinking about repacking the bearings, but I think Iām just going to upgrade instead. Do you have the product link for the SDK bearings that you used? I have replaced bearings on the G0704 before. Iām assuming itās a similar process, but I was curious if you had any tips?
3.) And finally, do you have product links for your marathon motor and VFD?
I apologize if this information was in a past reply. I donāt have my computer this afternoon, so I was reading through it on my phone and typing this up.
Iāll get back to you as soon as I can. Taking my girls for a Christmas tree today.
I only have a few minutes before I need to leave for an appointment so I give you a few answers.
The oil seal is pretty common but not available everywhere. If you pry the seal out you will see #s on it like 72 45 and 10 (or similar #s) I canāt remember the OEM size right now. I tried lubricating the oem seal but it did not help. the 45 or similar # is the inner diameter in mm. This is the one you want to increase. I will have to check my mill later but I think I went 2mm over. 1 was not enough. I just googled 45x72x10 oil seal and similar #s to find the correct one. AVXSEALS.COM is a good source.
Got to go. Iāll follow up later with more.
The tapered bearings are 30206 and 30207. There are various letters after those #s. Check the sdk website for definitions. I have found that, for this application, they are not all that important but some may be undesirable. I usually just search eBay for these. They can be quite expensive from suppliers. There are other comparable SDK bearings. My main search parameter for these was the max rpm. I am pushing mine to 6k so I went with the highest rating I could find.
BTW. The one oil seal is 45mm. I am using 47mm.
The process for changing the bearings is very similar to my PM-25MV (similar to the G0704) with the addition of some ring retainers. make sure you have a good set of ring pliers. one of the rings is quite large. I donāt have a bearing press so I have made up some jigs to press them on by hand, but by far the biggest help is to put the spindle in the freezer before installing the new bearings on it. I so the same with the races before installing them in the quill.
The marathon motor is a MARATHON Y526 Electric Motor NVD145THTN8029ABP. These are very expensive motors. It is an Inverter Duty motor. They can handle low speeds without overheating and maintain higher torque at low speeds. I found this one one ebay freight damaged for $225. You can find them for under $500 used or freight damaged. Marathon BlackMax motors are also very good.
The VFD is Lenze AC Tech, AC Drive 2 HP Inverter ESV152N02YXB. Nothing super special about it, it is just capable of Sensorless Vector modes.
I chose to go this way because of the extreme low rpm torque that these motors are capable of. It has to be coupled with a sensorless Vector VFD (pretty common) in order to function this way. I do quite a bit of rigid tapping at low speeds and most motors are very underpowered at a nearly 1:1 ratio and low rpms. There are other motors capable of this. This motor just fell out of the sky and was too good of a deal to pass up. (The motor mount on the mill has to be modified. especially if you have a PDB.)
Otherwise the motor is way too expensive new. Do some research on Sensorless Vector VFDs and invertor motors. https://www.wolfautomation.com/blog/most-recommended-vfd-for-bridgeport-mills/ is a good source. The motor and VFD choice are dependent on how you intend to use the mill. If your controller is not capable of rigid tapping or are not going to tap the decision is much easier and motor selection $ goes down. The stock motor may be sufficient. The VFD is a nice add even to the stock motor because it is much easier and safer to add speed control trough G-code. This eliminates the ground looping that has to be isolated with analog controllers like the oem controller.
I hope I havenāt confused you on the VFD and motor situation. It is all much more complicated than I make it out to be. Basically it is an expensive upgrade. If you just want to add some Gcode speed control and the added benefit of being able to fine tune the motor and possibly gain speed, power, torque or multiples of these, then the vfd is the way to go. There is a learning curve on the tuning, but it isnāt brain surgery. For me, I only replaced the motor to gain low speed torque and power. The VFD helped achieve this as well as a 6000 rpm spindle at a nearly 1:1 ratio.
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One thing I will say about the Lenze AC Tech SV VFDās is that they are very well documented and easy to learn how to adjust them.
This is exceptionally helpful. I found a good deal on Ebay for the bearings and was able to get the pair for $30. Hopefully, they are genuine SKF. There were not any letters after the numbers, but it seems like the base bearings can support 9k RPM comfortably. Besides the motor and bearings, how much does the design of the spindle affect the maximum RPM? I guess a better way to phrase this question is what is the maximum RPM you could run on the 833TVās spindle without having to worry about balance? Being able to cut at 9k RPM might be a future goal if it is possible.
Greg over at Priest tools is putting together a PDB kit for me. I still donāt have a lathe at my disposal, so purchasing a kit was my best option. Im curious to see how much modification would be required to drop in a marathon motor with that PDB installed. Iām assuming a mounting plate would be needed at the very least.
Up until about 500 RPM the stock motor has no torque, but I usually just run it on max RPM and tap by hand. Rigid tapping would be very niceā¦ but I need to invest that time and money upfront.
Thanks again for taking the time to write everything down. Iām sure others will find it useful like myself!
No problem. As far as the mounting plate for a marathon motorā¦ I used the stock mounting plate. Used my pm-25mv to cut a larger hole that is centered further back to create more room for the PDB. It mounts to the head using the same slots and bolts. I also cut out the mounting plate above all 4 socket head bolts that mount the mounting plate to the head. This is a bad design in my opinion. There isnāt enough room to get a standard Allen wrench on the bolts.
Iām not sure how fast the spindle is balance to. Mine seems comfortable at 6k. Higher rpms would require a higher pulley ratio and result in a higher, minimum rpm and decreased spindle HP and torque at all speeds. All electric motors have a max safe rpm. The best motors will have a 5400-6000 max rpm and most VFDs go to 500hz. I donāt recommend going beyond a stated max safe operating speed on a motor. For instance, my motorās MSRPM is 5400. Itās base rpm is 1800 at 60hz. To get the 5400 the vfd needs to be at around 180hz. You can go with higher spindle rpms by changing the ratio but this will lower your spindle HP and torque at all speeds.
It is a balance between capabilities and needs. The only way to get both very low speed torque and very high speed is with a 2 speed belt or gear system like the 833T.
In regards to the stock motor having no torque at -500rpm, a vfd may improve that. Especially a sensor less vector VFD. The results are not predictable without more info on the motor. For comparison, my marathon motor is rated at full torque at 1hz which is about 30 rpm when running on a constant torque setting. Most of this data is not available for general duty motors. Only inverter duty motors supply this data.
Canāt wait to see your PDB from priest tools. I considered their PDB for my 25mv but I wanted to customize it for a larger motor so I designed my own.
Todd Candee
Todd@thecandees.com
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That 9k RPM spindle is still very far off in my mind. With these benchtop mills, you have to be conservative when it comes to the feed per tooth, so the only way to make parts quicker is to spin that tool faster. You pointing out the need for appropriate gearing to achieve these high speeds and the loss of torque at low speeds is duly noted.
I will upload some pictures when the Priest Toolās PDB arrives. I was told 3 weeks lead time, so this will be an after the holiday upgrade.
Thanks again for all your advice!
Man, to hear you guys talkā¦inspiration! Now im in the software side of the houseā¦I tell you this stuff is crazy interesting. But I can tell itās easy to get caught up on something simple. David, Iāve mirrored your build almost precisely minus the probe and tool setter. I still have debian 10 installed so as of right now I wonāt be using probe basic. Iām just wanting to finally see this thing come alive this weekend. Question is, when setting everything Iām in pncconf what is your ip address? I was using this guys walkthrough but he seems to have his w3 jumper in the up position. Or did you just type āip addr showā in the terminal to get yours? Iām also working through exactly which drop downs to use on each particular pin in the Wizard for the mpg.
Well. After messing with it for several hours Iāve gotten no further. Itās the configuration of the Ethernet part im not getting.
Hey sorry I am at work late tonight!
I really didnāt use pncconf. I just edited the HAL and ini files directly.
I moved the jumper to the up position and I set it to 10.10.10.10 by making sure the following code was at the top of my HAL file:
loadrt hm2_eth board_ip="10.10.10.10" config="firmware=hm2/7i76/7i76e.BIT num_encoders=1 num_pwmgens=0 num_stepgens=3 sserial_port_0=2xxxx"
I think I followed that forum post originally.
Edit: If you are following my build closely you can just copy my wiring diagrams and download my Hal and ini files that are on the CNC mill project page. Just delete any lines that refer to the probes.
Just to confirm, your w3 jumper is opposite than that of the jumper diagram. Or am I backwards in my thinking?
I think Iāve about got it whoopedā¦hopefully. At least I can now see the mesa card. But my ping is not so good. Im gonna update the Intel ethernet card in the morning.
Anybody having issues with the spindle splines chattering? I had this issue on my pm-25mv as well. I was hoping this mill would have better spline tolerance but I guess not. This chatter causes poor surface finish.