I'm drilling a fair number of 1-5/16 holes in birch at an angle of 39 degrees to normal and the drill press chuck keeps coming loose. The bit is a new LV saw tooth bit. When the bit is entering the work there will be some lateral load but I can't avoid this until the entire bit is in the work.
I've cleaned the male and female surfaces of the taper so that there is nothing on them, to the point of wiping them down with organic solvents.
Any suggestions as to how to keep the chuck in place?
RB
For the morse taper, look for any burrs on the shank and stone them off. For the spindle, a morse taper reamer - hard to find and expensive, but also usually not required. There are morse taper cleaners, a plastic device like this:
Same rules apply to a jacobs taper, however I've not seen a jacob's taper reamer.
Angle drilling or for that matter, any side loading can and will eventually, work a Morse Taper loose. However, a resetting (slight blow from a brass hammer) after each initial angle is cut should help to keep the chuck and bit from flying off into "damit" land.
You might also check that the tang is not bottoming out. Some of the import DP are notorious for short spindle holes.
Dave
I'm guessing you may be talking about a Jacobs taper instead. Female taper on chuck / male on spindle?
Make sure the mating surfaces are not just clean, but free from burrs. Then you can seat the chuck by hitting it with a mallet (with the jaws fully retracted), or pressing it with a wood block.
If you heat the chuck to 200 degrees or so before seating, it will shrink onto the spindle and grip a bit tighter.
In the end, though, you may always have problems. Tapers were not meant for side loads.
John Martin
Also the more flutes you have the less pounding against the chuck & machine. Cause a 2 flute drill will do alot of pounding.
The Jacob's taper is solid. What is coming loose is a Morse taper. Female in the quill and a male from the chuck assembly.
I can't see or feel any burrs. I haven't yet attempted to drive it in. I'll try that in the morning.
Agreed, but its hard with a radial drill press to not have some side load when drilling off normal.
why not trying to make a jig so that side load is minimized .
Bore a 1-5/16" hole in a piece of say 1" board then cut the base of the board at 39 degrees. clamp the board to the work at the prescribed positionand bore the hole . The jig should take the side load off of the taper also can be used as a guide to position the hole......mjh
as a work around try this: take a block of something slippery. it could be umhw, delrin, lignum vitae, maple soaked in motor oil.... whatever. drill the hole in it at
90 degrees. either drill it with the bit hanging over the edge or cut through the hole after drilling it. in any case, you want to end up with enough solid material on the non half of a hole end to hold on to. now, when you go to start your angled hole, use the gizmo you just made to apply a balancing load to the bit- pushing in from the side. you'll probably only need it for a moment at the start of the cut.be very careful doing this.
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