DAPPH
as dyslexik as I'm daft
- Messages
- 6,474
- Location
- Near to Cross Hands Llanelli SouthWales GB
I've always noticed that my NU_TOOL drill press I purchased 30years ago wasn't quite true in alignment . You can adjust the table to tilt left or right to get a perfect vertical but almost since the day I purchased it , I've known it is a few thou out on the forward/ back axis by almost 12 thou ( with feeler gauges ) in nearly 3 inches of travel .
I checked it with a bit of precision rod out of a scraped inkjet printer in the chuck using a 2 inch M&W inverted precision engineers square . Rotating the chuck a few degrees several times by hand to check the chuck was on OK and the quill shaft is not bent .
It set me thinking , could I take the table off and check the accuracy of the swivel joint which ought to be 90 degrees or perhaps dismantle the whole machine and attempt to sort out the mating face difference on the clamping collar . On taking the drill table off I put a bigger engineers square on the table top face and discovered the the right angle mating face to the pedestal collar was the wrong angle. It was way out of being a right angle , nearly an 1/8 of an inch from back to front of the table plate .
Had a T.E.A. session as I drank a mug of coffee ( Think . Evaluate . Act . )
Realised that I might be able to take the QCTP off my lathe and mount the drill table on the compound slide upside down . Use a bit of key steel to get it at right angles to the face of the opened 4 jawed chuck & lock it down . ( Also to clear the compound slide handle etc.
)
Then sat a lathe cutter at an angle in the four jaw chuck so the cutting tip would just touch the face to be cleaned up and act like a decent slow speed fly cutter .
.
Dropped the lathe speed to the slowest it will run without using the back gear set up and very slowly & gingerly started to feed the saddle to the cuck till the plate just got the barest of skims . Locked the carriage and started the compound feed in 1 thou cuts , sixteen passes & half an hour or so later the whole mating face has been resurfaced to 90 degrees to the table face . Fingers crossed & hoped the bed and the head stock are reasonably accurate in being 90 to each other
.
On reassembling the drill press & repeating the vertical checks in several direction, I'm as pleased as punch . I've now managed to attain better than a 1.5 thou feeler gauge accuracy over 3 inches of the test rod as I cant get the blade
in anywhere between the inverted square and the checking rod using that thickness of feeler blade ..
I checked it with a bit of precision rod out of a scraped inkjet printer in the chuck using a 2 inch M&W inverted precision engineers square . Rotating the chuck a few degrees several times by hand to check the chuck was on OK and the quill shaft is not bent .
It set me thinking , could I take the table off and check the accuracy of the swivel joint which ought to be 90 degrees or perhaps dismantle the whole machine and attempt to sort out the mating face difference on the clamping collar . On taking the drill table off I put a bigger engineers square on the table top face and discovered the the right angle mating face to the pedestal collar was the wrong angle. It was way out of being a right angle , nearly an 1/8 of an inch from back to front of the table plate .
Had a T.E.A. session as I drank a mug of coffee ( Think . Evaluate . Act . )
Realised that I might be able to take the QCTP off my lathe and mount the drill table on the compound slide upside down . Use a bit of key steel to get it at right angles to the face of the opened 4 jawed chuck & lock it down . ( Also to clear the compound slide handle etc.
)
Then sat a lathe cutter at an angle in the four jaw chuck so the cutting tip would just touch the face to be cleaned up and act like a decent slow speed fly cutter .
.
Dropped the lathe speed to the slowest it will run without using the back gear set up and very slowly & gingerly started to feed the saddle to the cuck till the plate just got the barest of skims . Locked the carriage and started the compound feed in 1 thou cuts , sixteen passes & half an hour or so later the whole mating face has been resurfaced to 90 degrees to the table face . Fingers crossed & hoped the bed and the head stock are reasonably accurate in being 90 to each other
.
On reassembling the drill press & repeating the vertical checks in several direction, I'm as pleased as punch . I've now managed to attain better than a 1.5 thou feeler gauge accuracy over 3 inches of the test rod as I cant get the blade