Bristol Erikson QC30 toolholders as used on some bridgeport models and a few others locates on the machine with a locking cam ring on the end of the spindle forcing a iso30 spec taper into the socket rather than a drawbar above the machine. The advantages, you dont need access to reach above the machine to change the tool and its quick to do a toolchange. The problem is they have a reputation for coming loose in use and dropping out and they have to have that flange in place and be to spec.
Ive recently unboxed about 12 brand new ER series collet chucks + a couple of other holders, from a well known uk seller of far eastern origin tooling that I got free in a deal for something else, and going over them, 6 have flanges 0.4mm too thick to even go into the cam ring, and one has one 0.4mm too thin so when its in and engaged, it is right on the verge of coming out. Theyre not holding tight enough tolerance on that flange to meet the required qc30 specs.
I have gone through the grief of making a 0.4 shim to hold the sloppy one snug in the machine and loctited this on, but if I had of just used it as is instead of measuring, I am sure I would have been one of those people saying how bad qc30 was as a tooling system. Grief because if you take the toolholder as is, the cut outs for the cam pins to pass would turn a normal round shim into two seperate pieces, so I had to hard turn the body of the toolholder down a few mm to give some material to keep the two halves connected. Fortunately its a jacobs taper adaptor not a thinwall collet holder so had enough meat to do this. Grinding a shim to 0.4mm thick was fun getting it to stay on the magnetic chuck until I superglued it to a bigger lump of steel to clamp...
For the too thick ones, Im going to rig them up in the surface grinder on the spindex and take the flange down 0.4mm when some ER collets turn up, I plan to grind a pin in the spindex to a diameter then clamp the ER toolholder onto the ground pin and provided the collet is concentric it should be true, but its not critical all the same. Easy fix, if you have the machine to do it or know someone who has, if not, you can take a offhand grinder and just touch the flange lightly at the toolbit end and thin it ever so slightly at a time until it will engage solidly. Do this on the tool side of the holder not the taper, and you will not be altering the reference surface it clamps into the machine with.
I havent had one come loose yet, maybe the reputation is all because of bad tolerances on that clamping flange with cheap toolholders. Checked the rest of my tooling and the original Bristol erikson holders are all within 0.05mm on that flange thickness. If I paid for these, theyd be going back with a note as to why.
Posting, might save someones machine table or worse one day for want of a few minutes with a digi caliper measuring up flange thickness.
TL,DR; Measure yer flanges qc30 peeps
Ive recently unboxed about 12 brand new ER series collet chucks + a couple of other holders, from a well known uk seller of far eastern origin tooling that I got free in a deal for something else, and going over them, 6 have flanges 0.4mm too thick to even go into the cam ring, and one has one 0.4mm too thin so when its in and engaged, it is right on the verge of coming out. Theyre not holding tight enough tolerance on that flange to meet the required qc30 specs.
I have gone through the grief of making a 0.4 shim to hold the sloppy one snug in the machine and loctited this on, but if I had of just used it as is instead of measuring, I am sure I would have been one of those people saying how bad qc30 was as a tooling system. Grief because if you take the toolholder as is, the cut outs for the cam pins to pass would turn a normal round shim into two seperate pieces, so I had to hard turn the body of the toolholder down a few mm to give some material to keep the two halves connected. Fortunately its a jacobs taper adaptor not a thinwall collet holder so had enough meat to do this. Grinding a shim to 0.4mm thick was fun getting it to stay on the magnetic chuck until I superglued it to a bigger lump of steel to clamp...
For the too thick ones, Im going to rig them up in the surface grinder on the spindex and take the flange down 0.4mm when some ER collets turn up, I plan to grind a pin in the spindex to a diameter then clamp the ER toolholder onto the ground pin and provided the collet is concentric it should be true, but its not critical all the same. Easy fix, if you have the machine to do it or know someone who has, if not, you can take a offhand grinder and just touch the flange lightly at the toolbit end and thin it ever so slightly at a time until it will engage solidly. Do this on the tool side of the holder not the taper, and you will not be altering the reference surface it clamps into the machine with.
I havent had one come loose yet, maybe the reputation is all because of bad tolerances on that clamping flange with cheap toolholders. Checked the rest of my tooling and the original Bristol erikson holders are all within 0.05mm on that flange thickness. If I paid for these, theyd be going back with a note as to why.
Posting, might save someones machine table or worse one day for want of a few minutes with a digi caliper measuring up flange thickness.
TL,DR; Measure yer flanges qc30 peeps