Startrite Drill Press(benchtop) – stuck chuck

[Jim Dalton 1Participant @jimdalton1]

Hi all

Picked up a Startrite Mercury 5 speed benchtop drill press the other week. I knew buying it that the run-out on the chuck wasnt perfect but took the chance as it possible was a good price.

Unfortunately I can't remove the chuck. As far as I can see, there are two knurled nuts, but the top one isn't accessible. Probably best described by photo below. Any thoughts on how to fix?

[Jim Dalton 1Participant @jimdalton1]

[Mike PooleParticipant @mikepoole82104]

The shiny part shielding the top nut appears to have been added, if you remove the screws holding it it may give you the access you need.

Mike

[Clive FosterParticipant @clivefoster55965]

Plenty of pictures of the small startrite drills which may help here :- **LINK**

Agree with Mke that the shiny ring needs to be removed for better access. Chuck doesn't look right. Should be a male JT 33 taper on the spindle for the chuck to fit on. The threaded rings are really to hold a JT33 to MT1 adapter sleeve. Pictures in the link above. Theoretically unscrewing the lower ring would force the standard chcuk off but I have my doubts.

I'd be doing something clever with a pair of chuck wedges and some sort of clamp to draw them together so forcing the chuck off.

Last time I saw a set up looking like that, complete with runout too, a sort of metric B series taper chuck had been pushed onto a JT spindle. On examination chuck body taper was sort of in between JT and B series! Presumably so it could eb forced onto either and stay put.

Speeds are rather high for metalworking. Seriously consider slower motor, three phase and VFD or inverting the motor and fitting an extra shaft with suitable speed reduction pulleys. Rob a defunct spin drier for a suitable shaft and bearing unit, maybe a pulley too.

Clive

[Jim Dalton 1Participant @jimdalton1]

thanks guys.

[Dave HalfordParticipant @davehalford22513]

Startrite also make woodworking machinery

[HacksawParticipant @hacksaw]

And kids shoes…

[Jim Dalton 1Participant @jimdalton1]

Managed to get the chuck off. Measured the run-out at the end of JT spindle and am getting .050mm run-out. Although chuck looks in good order, it's a Rohm.

[Howard LewisParticipant @howardlewis46836]

0.05 mm (0.002" ) run out does not sound too bad for a drill press, rather than a jig borer..

The chances are that your drills will not have absolutely equal length cutting edges, either, so will cut oversize!

If the chuck arbor is mounted in an adaptor, maybe that is the source of the run out? It should not be, BUT!

If you can remove the adaptor, is the MT section undamaged?

Is the MT in the quill undamaged? They are both possible sources of inaccuracy.

Any play in the bearings for the quill, that might be allowing the run out?

HTH

Howard

[Jim Dalton 1Participant @jimdalton1]

Thanks Howard. Will check those items. I assume that the chucks themselves tend not to be most source of runouts?

[Howard LewisParticipant @howardlewis46836]

As far as I know, Rohm chucks have a good reputation.

But bear in mind that they are drill chucks, so probably not as accurate as a collet chuck of equal quality intended to hold cutters or work.

Howard

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