- Joined
- Jul 29, 2014
- Messages
- 2,725
Yep, an old thread, but kind of interesting. If my Asian brand collets didn't fit, boring out the inside of my spindle would be one of the last things I'd think of. If ever.
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R8 Insert Deflection
- Thread starter Bill Kirkley
- Start date
Have not read all but some general comments.
OP stated 44 pounds applied force and interstate collets.
Is interstate a brand or type?
If it is labeled as R8 and does not fit then either collet is bad or mill is bad, easy.
Get a known good brand, does not need to be bridgeport. Harding or many others.
We have assorted Chinese and American from the used parts bin and new and all fit the bridgeport fine.
If the good one fits then mill good collet bad, ifnofitthen warranty.
Never modify the machine to fit the tooling.
44 pounds side loading...the servo power feed is rated in fairly high torque combined with the gear ratio of the lead screw.
Side load is much higher than 44 pounds.
Combine the actual cutter interface load it can be more.
Place a 1/2 inch dull end mill in your fixture and see how much weight it takes to break it, likely more than 44 pounds.
Sent from my SM-G781V using Tapatalk
Just noticed very old thread...oops...
Still, never modify the machine to fit the tooling, the tooling is throw away so modify that or toss it.
If new send back...
OP stated 44 pounds applied force and interstate collets.
Is interstate a brand or type?
If it is labeled as R8 and does not fit then either collet is bad or mill is bad, easy.
Get a known good brand, does not need to be bridgeport. Harding or many others.
We have assorted Chinese and American from the used parts bin and new and all fit the bridgeport fine.
If the good one fits then mill good collet bad, ifnofitthen warranty.
Never modify the machine to fit the tooling.
44 pounds side loading...the servo power feed is rated in fairly high torque combined with the gear ratio of the lead screw.
Side load is much higher than 44 pounds.
Combine the actual cutter interface load it can be more.
Place a 1/2 inch dull end mill in your fixture and see how much weight it takes to break it, likely more than 44 pounds.
Sent from my SM-G781V using Tapatalk
Just noticed very old thread...oops...
Still, never modify the machine to fit the tooling, the tooling is throw away so modify that or toss it.
If new send back...
Last edited:
- Joined
- Sep 22, 2019
- Messages
- 89
Your fix was simpler than mine!I know this is an old thread at this point - but this method worked amazingly well for me on my PM727. After bluing I felt like my spindle was concentric. I checked the collets for size and they were 0.949 - well within spec. Oddly over the past year of use the spindle was getting tighter. I used a dowel and some emory cloth and it cleaned it up perfectly. The collets slip right in now (it had gotten where I needed to use a soft blow hammer to get them in).
Instead of using a drill I just ran the mill about 200rpm and moved the dowel by hand up and down in the spindle bore.
- Joined
- Sep 22, 2019
- Messages
- 89
Never Say Never!Have not read all but some general comments.
OP stated 44 pounds applied force and interstate collets.
Is interstate a brand or type?
If it is labeled as R8 and does not fit then either collet is bad or mill is bad, easy.
Get a known good brand, does not need to be bridgeport. Harding or many others.
We have assorted Chinese and American from the used parts bin and new and all fit the bridgeport fine.
If the good one fits then mill good collet bad, ifnofitthen warranty.
Never modify the machine to fit the tooling.
44 pounds side loading...the servo power feed is rated in fairly high torque combined with the gear ratio of the lead screw.
Side load is much higher than 44 pounds.
Combine the actual cutter interface load it can be more.
Place a 1/2 inch dull end mill in your fixture and see how much weight it takes to break it, likely more than 44 pounds.
Sent from my SM-G781V using Tapatalk
Just noticed very old thread...oops...
Still, never modify the machine to fit the tooling, the tooling is throw away so modify that or toss it.
If new send back...
PM wanted me to take the mill apart and send them the spindle. That was something I did not feel comfortable doing.
As for sending it back, that would entail rehiring a rigger to remove the machine, then paying to have it shipped.
Modifying the machine was the simplest solution. It not only worked, it was cheap.
No doubt most think this was a radicle solution, but for me it was an easy fix, it solved the problem and it was fun!