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- Dec 18, 2013
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I thought I would detail this procedure here for those like me who have never owned or operated a Bridgeport type mill and save you chasing around looking at manuals and procedures.
Issue: The collet alignment screw in the spindle of my PM 935TV was properly installed at the factory, the issue is apparently a lot of R8 tools and collets are not manufactured to R8 specs with respect to the depth of the keyway slot in the tool. Its supposed to be .094 deep but two of my three R8 tools (ER 32 collet chuck, Face Mill) were out of spec significantly, over .020 shallow and I could not insert the tools in the spindle.
Further research showed historically the collet alignment screw has a habit of snapping off when you spin a collet or tool in the spindle jamming between the spindle and the quill creating quite a problem. I myself had this happen to me years ago. So I elected to remove the collet alignment screw and kill two birds with one stone.
Reference Schematic
1. There is a grub screw 6 on the back side of the quill 142, this requires a 2.5mm Allen wrench.
2. The collet set screw 140 and grub screw 6 are in the spindle, both require a 3mm Allen wrench.
3. The nose piece 133 needs to be removed to gain access to the collet set screw, this will require a pin wrench.
Here is my 'no fab' pin wrench I assembled with $14 of parts at my local hardware store. Talk about easy the holes were pre-drilled I just screwed it together in a couple of minutes. The pin holes are .190 inch so I just used a couple 10/24 screws, 1/2 inch and 3/4 inch lengths so that the tips were flush with each other. A short 3/8 bolt holds the two together. The nose piece was not that tight, this was plenty stiff enough to R&R it.
Step 1 - loosen the grub screw on the back side of the quill with a 2.5mm Allen wrench. You will need to extend the quill to reach it.
Step 2 - Using the pin wrench remove the nose piece, its reverse threaded you need to turn it COUNTER CLOCKWISE standing in front of the mill looking down at it. Remember you are looking at it upside down so turn the wrench counter clockwise from the left side of the mill to the right side of the mill. Some crud fell down in that ring of grease, I carefully cleaned it out of there.
Here's the other side, I elected to apply some anti-seize to the threads when I re-installed it. It wasn't ridiculously tight when I loosened it, just good and snug so I didn't overtighten it when I reinstalled it.
Step 3 - Remove both the outer locking grub screw and the inner collet alignment screw with a 3mm Allen wrench. These are standard thread turn counter clockwise to remove.
Here they are removed.
Issue: The collet alignment screw in the spindle of my PM 935TV was properly installed at the factory, the issue is apparently a lot of R8 tools and collets are not manufactured to R8 specs with respect to the depth of the keyway slot in the tool. Its supposed to be .094 deep but two of my three R8 tools (ER 32 collet chuck, Face Mill) were out of spec significantly, over .020 shallow and I could not insert the tools in the spindle.
Further research showed historically the collet alignment screw has a habit of snapping off when you spin a collet or tool in the spindle jamming between the spindle and the quill creating quite a problem. I myself had this happen to me years ago. So I elected to remove the collet alignment screw and kill two birds with one stone.
Reference Schematic
1. There is a grub screw 6 on the back side of the quill 142, this requires a 2.5mm Allen wrench.
2. The collet set screw 140 and grub screw 6 are in the spindle, both require a 3mm Allen wrench.
3. The nose piece 133 needs to be removed to gain access to the collet set screw, this will require a pin wrench.
Here is my 'no fab' pin wrench I assembled with $14 of parts at my local hardware store. Talk about easy the holes were pre-drilled I just screwed it together in a couple of minutes. The pin holes are .190 inch so I just used a couple 10/24 screws, 1/2 inch and 3/4 inch lengths so that the tips were flush with each other. A short 3/8 bolt holds the two together. The nose piece was not that tight, this was plenty stiff enough to R&R it.
Step 1 - loosen the grub screw on the back side of the quill with a 2.5mm Allen wrench. You will need to extend the quill to reach it.
Step 2 - Using the pin wrench remove the nose piece, its reverse threaded you need to turn it COUNTER CLOCKWISE standing in front of the mill looking down at it. Remember you are looking at it upside down so turn the wrench counter clockwise from the left side of the mill to the right side of the mill. Some crud fell down in that ring of grease, I carefully cleaned it out of there.
Here's the other side, I elected to apply some anti-seize to the threads when I re-installed it. It wasn't ridiculously tight when I loosened it, just good and snug so I didn't overtighten it when I reinstalled it.
Step 3 - Remove both the outer locking grub screw and the inner collet alignment screw with a 3mm Allen wrench. These are standard thread turn counter clockwise to remove.
Here they are removed.
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