So i got a bit of rust on the x ballscrew where bridgeport had an open are under the table. I have some bronze wool and some citric acid coming in. I figure ill try to get the rust off, and may even polish afterwards, not sure here. Its a $1000 mill so not sure how much it makes sense to spend on it. The screws seem like they are in very good shape otherwise.
Attachment 437034
The ways on the table look like there is very little wear and cleaned up nice:
Attachment 437036
One area I have been debating with myself is weather or not to replace all the way oil meetering valves. This mill is 25 years old, but clearly low hours. I have looked, and there are a ton of these things. I'm sure Id spend 500+ to replace them all. thoughts?
Boss 8 belt size with servo:
y axis 240h100 gates
.5 pitch, 1" width, h belt, 24" long, 48 tooth
x axis 220h100 gates
.5 pitch, 1" width, h belt, 22" long, 44 tooth
z axis 270h075 gates
.5 pitch, .75" width, h belt, 27" long, 54 tooth
Anyone know if the timing belt on the spindle low gear is the same a regular Bridgeport?
The coolant chip guard is the same as this one:
Looks like its in great shape ! i would think if you see a ALL the ways being lubed you should be good.. or possibly figure a single point hookup before each metering valve ... and you could do a good visual since the table is off..
would be interested in the chip guard if the price is right.. pretty simple design tho... could possibly make one as well...... lmk !
thanks
Joe
The Belt is a regular Timing Belt just measure it and you can get a replacement I may have one if you have the size that you have
That C3 Ballscrew does not look so good with the rust on it, it looks like it has never had enough oil on it which can be a problem with the standard oil pumps on these machines
Here is a photo of my table guard I made from 1/8" Aluminum sheet the corner posts where milled from bar stock the 2 ends just slide in which you can remove for long parts
And Y axis Ballscrew after more than 15 years of use it does have custom way covers though
Mactec54
No the Guard if mounted to the back flange of the table on the inside so the drainage and all T slots are clear along the back, this only works if you have the Boss Tables it has 3 1/4-20 SS screws that hold the back it in place and the corner posts have 2 10/12 tpi SS button head screws as well, it gives you the full table to use
Yes the oilers need to be replaced the one's I have used are not cheap but run at 170 PSI 150 PSI is ok like this pump here they are every where so you can some times find a good price
https://www.ebay.com/itm/202834043075
Mactec54
thanks for the pic Mac... well as far as the oilers are concerned i actually dis-assembled the Bijur cleaned it thouroughly, changed the filter and tested it completely.. you have to be careful as some of the motors ( which look alike ) and all of the complete pumps pump at different rates... due to the timings of the pumps... and there are adjustments to the stroke of the pump.. and finally i bench tested it for 2 days and measured the output...
now, this prompted me to look at my 2 boss' y screws... ( both machines are in a state of construction and havent been used in years... )
so this made me think that maybe db's machine is just rusty from sitting .. possibly outside ? as we find many of these machines outside in the elements.. or in a un conditioned building...
I think that's the case it sat for quite a while, I have had it for 4 years and the guy beforeme had it for a long time too. The ballscrew looks great except for the one section next to an opening where moisture could get at it more directly. I took brass wool to it and got off as much as possible, the nut moves smoothly through that section so I'll let it go as is.
Ive been plugging data into the calculator at https://www.servotak.eu/tools/engineering_calculator
Now I'm starting to think that the 400w DMM servo would also be a good match for the boss. this is showing what each would do assuming 500kg mass being moved, and this is probably a bit higher than what I'd use unless I had a heavy 4th axis up there. The 400 wat motor is seeing a 5:1 inertia ratio. the 750w motor is seeing a 1:1 both supposedly are good. here you can see the machine force each would support. I suspect I wouldn't exceed the force the 400 wat motor can support.
thoughts?
400w:
Attachment 437990
750w:
In theory and calculations are good but not always give you the right answer 750W is what you need for this machine I have used the 400W on another mill but needed a 2:1 gearing on the same pitch screw to make it work, and the Boss is a much heavier machine to move than the small Jet Mill I use the 400W on, so I would not go that route, they won't have enough power / torque to get your machine working how it should
A 400W motor will move your machine but will always be faulting out once you start cutting anything
You missed one box Force Weight in those calculations the Tables are 450Lbs and the Saddle is 200Lbs
Mactec54
Ok lots of progress on this project. I have purchased 4 750w DMM servos w dyne 4 drives. I also bought all the broachs, reams, and pulleys so I can make pulleys and fit the new motors up. The electronic cabinet is cleared out and ready for the new parts.
I have a pretty decent model of this machine now thanks to days of measuring and drawing:
Attachment 439354
Now to figure out the new servos:
x:
Attachment 439364
y:
Attachment 439360
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Quill:
Attachment 439358
Knee:
Attachment 439356
For the Base I want to do something kind of like this:
Attachment 439366
And a chip tray for chips and coolant:
Attachment 439368
More on next Post.
Basic Idea of shape for enclosure, I'll add doors to it and a tube steel skeleton:
Attachment 439370
Did I mention I will also make the chip tray slide out from the bottom for easy cleaning? but I don't have that all designed yet:
Attachment 439372
I Also bought a graymills 1/2 hp coolant pump off ebay for a decent deal, and will make a coolant tank under the left side of the chip tray, saw some good ideas for it on a video about a off the shelf one.
Suggestions? Comments?
looks like you are making some good progress !!! my build has been sidelined for the moment but following along !
as far as coolant tanks.. im going to use the one i got with the machine.. ill be building a chip tray similar to the oem version and just be using the 2 table drains
I think a tank like that would work great if your using a table chip guard and your not flowing more coolant that the table drains can handle. I think my 1/2hp pump could probably overwhelm the table drains. I'm thinking of drilling some extra ones so I can control the way it flows off the table.
Mactec, after wrestling with the bijur oil pump for 2 days im ready to concede and purchase this pump you recommend.. any idea if it is the 4mm or 6mm model ? it will be coming from china so i want to be sure i order the correct one also i am going to pull the table to check the oilers is there any info or schematic on what metering orifices will be needed?
thanks
Joe
So its been a while since an update. I have mounted and made all the parts for x y and the knee for the servos. The Chinese timing belt pulleys I machined to fit my servos were total crap and I had to machine the teeth profile off of them and do a press fit with the original Boss pulleys I bored out. Now I am in the process of designing the actual parts to make the chip pan and enclosure I mocked up in previous post.
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