Drilling problems & remedies

[Bob McParticipant @bobmc91481]

Hi All..

I have had this bench drill for a year or so and have had problems with table movement,; if I tried to drill off the exact centre the table would start to tilt in the pressure direction..

Also, when I trammed for the 'nod' ie the tilt in the y axis, it was out by about 1mm over the diameter of the table, and I wondered if this was the reason I couldn't seem to drill a through hole through round stock with any accuracy.

After dismantling the table support arm it was apparent that the table movement problem was caused by the surface that the locking nut had to bear on, it had not been machined from the cast state and was severely angled from horizontal see pic below.

Below shows how much an angle there is.

Consequently the locking nut has only a small area of contact with the surface and therefore not much of a hold on the arm.

It can be very disconcerting when drilling a hole to see too late that the table is moving and if you have a similar machine I think it wise to have a look at this part.

I could have machined this surface and left it at that but the 'nod' tilt bothered me as well so I ditched the original support arm and stitched up an adjustable 'not tilt' support arm.

The table can now be adjusted and trammed up nicely referenced to the quill axis,…below..

…Bob..

[Bob McParticipant @bobmc91481]

New bench drill unstable support and new nod tilt mechanism.

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