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Author Topic: Bridgeport Knee Mill Conversion?  (Read 159184 times)

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Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #240 on: June 24, 2016, 03:46:29 PM »
From a quick scan back through the thread it seems a 1.8kw 3000rpm AC servo at 1:1 drive should be ok if i keep back-gear.

Its about £350 so not too bad.

Larger ones may be better but then top speed seems to drop to 2500rpm or 2000rpm so would need a ratio increase.

I have a feeling based on usage that it really does not need max spindle power at all.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #241 on: June 24, 2016, 04:25:10 PM »
I used steel for my brackets on the manual mill conversion, 10mm I think.
With Alu  I think if doing a long Y bracket like I did I would go 12mm, X would likely be fine in 10mm.
Hood

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #242 on: June 24, 2016, 04:34:07 PM »
Ok, great, i'll likely use 12mm ally then as its a good size for counter-boring bolt heads etc. The Y bracket I am sketching up at about 350mm long with the motor beneath the knee at about 5 o'clock angle.

The X axis will likely be towards the rear or below but the motor will probably have to stick out the end as most do due to it's size, this makes mounting harder but will not fit under the table as it hits the knee.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #243 on: June 25, 2016, 08:15:15 AM »
Well i spent a few hours trying to dismantle the motor this morning but could not even get the drive disc off the end so i don't think bearing replacement is on.

It's a toss-up between living with a grumbly motor or throwing one of these in...

http://www.aliexpress.com/store/product/NEW-1-8kw-AC-Servo-Motor-and-Drive-in-6N-M-1800W-3000RPM-with-Servo-Cable/314742_2037588952.html

A 2kw would be better but none listed at present.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #244 on: June 25, 2016, 11:52:50 AM »
I think 44 tooth HTD8 pitch x 30mm wide belt & pulleys will handle this ok.

Decided to go full servo - budget was busted long ago so might as well carry on and fracture it some more :)
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #245 on: June 26, 2016, 04:41:51 AM »
Can't recall what pulleys I have on the Beaver but the belt is 25 wide 8mm pitch. In fact even on the big lathe it is just 25mm wide and 8mm pitch and it has peak torque of over 150Nm and has run fine for probably 5 or 6 years. They both use Gates GT3 belts though which are supposed to be a bit tougher.

Hood

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #246 on: June 26, 2016, 05:52:23 AM »
Ok thanks, it makes little difference here as plenty of room in head for any width of belt, will check options before ordering.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #247 on: June 26, 2016, 06:21:55 AM »
Just looked in my BSL book and I am using 20mm wide belts on the Beaver, the Computurn and also on the manual lathe that I fitted a servo spindle to.
The Gates programme is pretty good for seeing what will work for different variables, it also gives you belt lengths and pulley sizes from the data you input, very handy wee programme indeed :)


Hood

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #248 on: June 26, 2016, 09:05:23 AM »
Had a chunk of 15mm plate laying about and decided to exercise my minimal CAD/CAM knowledge so made the Y axis motor mount plate.

Most impressed when it actually fitted 100% as intended :)
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Bridgeport Knee Mill Conversion?
« Reply #249 on: June 26, 2016, 01:40:09 PM »
Looking good :)
BTW just sent you a PM.
Hood