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Author Topic: Bridgeport Knee Mill Conversion?  (Read 158978 times)

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Re: Bridgeport Knee Mill Conversion?
« Reply #730 on: February 16, 2018, 06:46:48 AM »
It looks like to press those bearings off you will have to push on the outer races and that will more than likely ruin the bearings. Remember that these will be running your tooling and we want to keep the tool within tenths and not holding up somebodies utility trailer.
Be very careful with the threaded part since it is cast iron and can be broken very easily, DON'T ask how I know.

Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #731 on: February 16, 2018, 06:49:09 AM »
Thats a PITA, destructive removal :(

Will try some heat first, if not then its new bearing time if i can find a suitable part
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: Bridgeport Knee Mill Conversion?
« Reply #732 on: February 16, 2018, 06:55:14 AM »
The factory bearings are BIG $$$$$$$. I picked up some on eBay for a lot less. I believe that they are a 7207 AC bearing. Make note of how the old ones come off and reinstall the new ones the same way. Also look into getting some Kluber grease for the bearings. Very expensive but worth it in the long run. Someone may have an alternate suggestion instead of the kluber.


Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #733 on: February 16, 2018, 08:24:44 AM »
Would this happen to be a suitable pair...

https://www.thebearingcompany.co.uk/product.php?id_product=7419

Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: Bridgeport Knee Mill Conversion?
« Reply #734 on: February 16, 2018, 05:36:21 PM »
They look OK and P4 should be OK. I would only buy spindle bearings from a know manufacturer, i.e. not Chinese "German" bearings.
If these are overseas no-name bearings I would be very weary. Also verify against the numbers on your bearings. If you can find the specs of your original bearings that will give you a target to shoot for.

Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.
Re: Bridgeport Knee Mill Conversion?
« Reply #735 on: February 17, 2018, 01:27:29 AM »
I just discovered your thread today so I joined the forum to give you a thumbs up.

WOW - you have really done a lot on your Bridgeport.  Great Job!

I have a BOSS 5, QC30, original steppers, geckodrives, vfd, 4th axis with servo...  I also realized very quickly the limitations due to the limited quill travel and am interested in adding a stepper or servo to the knee as you have done.  Can you share the list of parts you used?  I assume you also did the mounting bracket in Fusion360?  That would be great to see as well.

You indicated you want to add an ATC.  I'm anxious to see how you implement that with QC30 (if that is your plan). 

Joe

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #736 on: February 17, 2018, 03:13:55 AM »
They look OK and P4 should be OK. I would only buy spindle bearings from a know manufacturer, i.e. not Chinese "German" bearings.
If these are overseas no-name bearings I would be very weary. Also verify against the numbers on your bearings. If you can find the specs of your original bearings that will give you a target to shoot for.

Mike

thanks, i'll verify the source.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #737 on: February 17, 2018, 03:18:51 AM »
I just discovered your thread today so I joined the forum to give you a thumbs up.

WOW - you have really done a lot on your Bridgeport.  Great Job!

I have a BOSS 5, QC30, original steppers, geckodrives, vfd, 4th axis with servo...  I also realized very quickly the limitations due to the limited quill travel and am interested in adding a stepper or servo to the knee as you have done.  Can you share the list of parts you used?  I assume you also did the mounting bracket in Fusion360?  That would be great to see as well.

You indicated you want to add an ATC.  I'm anxious to see how you implement that with QC30 (if that is your plan). 

Joe

Sounds like yo have a nice machine there, i've spent way too much on mine but i cant fit a normal VMC in plus i like the big bed I have, VMC's always seem cramped ;)

I'll be using the QC30 spindle with BT30 holders and a drawbar, should fit as i have been told plus it makes ATC a lot easier.

I used a 700w AC servo on the knee, it takes a fair bit of torque (I measured 8-10Nm) to get it moving, plus it matches my other drives, Belt is HTD5x15 and i'm using the stock Bridgeport bevel gears and screw.

I'll find a pic of the bracket but it was very easy.
I'll be using the
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #738 on: February 17, 2018, 07:04:56 AM »
I got the bearings off the spindle - this way....

Remove the locknut and washer, place splines in lathe chuck with packers to protect, get blow lamp, run lathe at low speed, aim heat at inner race-the spinning shaft ensures even heating. After a few minutes the bearing just slides off with a gentle start from a rubber hammer, rinse and repeat for each bearing but make sure to allow the shaft to fully cool between each cycle.

The bearings appear to be in good shape and i will refit them if only just to see if it works. I cleaned in a three-bath wash of white spirit going from dirty to clean then dried-off with paper towel and soaked in spindle oil (these will be going back with oil not grease), they feel slick and very smooth so i see no reason not to refit.

If it grinds itself to bits in a day then now i know how easy to change them it will only mean minimal down-time.

I have a feeling the hard part is going to be getting the spindle out of the quill - pretty certain I fitted a longer screw to hold the Z axis drive which will block removal of the spindle assembly. If that is the case it means stripping the Z drive down which is a bigger PITA.
« Last Edit: February 17, 2018, 07:07:00 AM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: Bridgeport Knee Mill Conversion?
« Reply #739 on: February 17, 2018, 02:03:38 PM »
Nice to see that you were able to remove them without destruction. I will keep this method in the back of my mind the next time I have to do somethinglike this.

Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.