Accurate Drilling Center Holes In Baffles

[Historian]

I was recently asked what were some of the techniques
that have been used to accurately drill out center holes
in thin metal disks.

I humorously said "Spider, man!".

I recalled seeing in 1955 a machinist's technique used by
the Institute's 'gumpy-Gaelic' shop foreman ... a lathe chuck
Spider.

I located a great YouTube presentation of a technique
for building the chuck Spider and its use to rapidly
center drill multiple 1" disks.

<< https://www.youtube.com/watch?v=MmHOlrxHJmk >>

Thought someone in future might find this useful.

Same technique could be used by mounting the lathe
chuck on holder to be held under drill press.

Best.

[ECCO Machine]

That's not a spider. Though some refer to such a part that way, it's just a chuck stop fixture. A spider is an attachment on the back end of the spindle with 4 screws for dialing in concentricity of a long part.

Also a very backwoods way of setting up to make 120°offset cuts cuts. Good grief. That's what rotary tables are for.

I make those fixtures on a regular basis for setting height and indexing baffles of different diameters to make indexing cuts & clip.

[Historian]

Ecco, great work!!

Just got back from hinterland and
enjoyed your update.

It is visual eye candy.

Your explanation is correct on Spiders.
They are also set up in front of lathe
for odd shaped barrel drilling.


Best.

And a Happy 'MOTHER's' Day to nasty DemoNrats