Chamfering Sprue Plate without chatter?

[detox]

I have a couple of 45 degree cutting tools (drill mounted) that are used for chamfering. Is there a may to sharpen a sprue plate hole smoothly without getting chatter using them. What works best for sharpening without changing the factory hole opening angle of sprue plate?

[country gent]

Easiest way to do this is to lock the sprue plate down on a drill press table. ( place a bock of wood under it to protect the table) Clamp it on location under the spindle. Chuck up the chamfering tool in the spindle and with a rod that fits the key holes in the chuck lower the spindle and turn it by hand slow and forcefully. It shouldnt take to much. Even this slow method will raise a burr on the bottom that needs to be stoned off before use. By turning slow by hand the cutter shouldnt chatter and should cut very cleanly.

[theperfessor]

Slow speed and a good cutting fluid will go a long way to solving a chatter problem.

[bangerjim]

Depends on how high a quality your press is and how much play or "run-out" there is in the quill. No amount of clamping will prevent chatter if the quill is wobbling around in the press. Check it. Just extend the quill down, grab it, and see if you can wobble it around.

The process you are trying to do should be done in a milling machine which has a LARGE solid quill and is totally rigid.

Good luck!

bangerjim

[Red River Rick]

Check the angle of your sprue well.

Most are cut using a 82 degree countersink (the standard for flat heads screws). Your 90 degree countersink will make the well larger on the top, since you mention you didn't want to change anything.

RRR

[Rattlesnake Charlie]

I've cleaned up mine using sandpaper. Start with 180. Sometimes I then go with finer grit. Usually don't have to. Smoothing up them up helps the sprues fall out easier.

[smokeywolf]

I've had better luck using a single flute countersink (Ford cutter) than the multi-flute; firm pressure, slowwww speed. Multi flute countersinks need to be used in a rock solid rigid setup.

smokeywolf

[detox]

Easiest way to do this is to lock the sprue plate down on a drill press table. ( place a bock of wood under it to protect the table) Clamp it on location under the spindle. Chuck up the chamfering tool in the spindle and with a rod that fits the key holes in the chuck lower the spindle and turn it by hand slow and forcefully. It shouldnt take to much. Even this slow method will raise a burr on the bottom that needs to be stoned off before use. By turning slow by hand the cutter shouldnt chatter and should cut very cleanly.

This method worked perfect...very smooth cut. My chamfering tool is actually a tad less than 90 degrees, which cleaned up the bottom cutting edge only

[country gent]

Doing it this way gives a very solid smooth cut that is very controlled. Sometimes big and fancy isnt always best. Another trick when tapping holes set up the same and turn the chuck by hand saves "flexing" the tap, keeps it straight and square makeing for cleaner better threads.

[detox]

You were right, it did not take much effort and only a few turns until sharp.