Re: [CAD_CAM_EDM_DRO] Re: NEW conversion project....

>
>
> > > Another issue, is someone overtightened a bolt or stud in the center
> > > T slot right at the center of the table.
> > >
> > > It broke a hole the width of the slot and about 3" wide along
> > > the length.
>
> I am not much of an electronics geek, but I am a long-time machinery
> junkie.
>
> I have bought machinery with damaged tables before and here are the options
> I have tried:
> 1. Use the mill to cut around the hole and braze a new piece of steel in
> place.
> Welding Iron needs careful prep including preheat and very slow cool
> down. It can be done, but it
> is unlikely that most people would be successful.
> 2. Mill the top of the right off using the machine it sits on, bolt a
> plate of steel to the top and mill it flat and
> cut new slots.
> This was fun in fact. It worked out really well - I bolted the plate
> on from the underside of the table. When
> I had a friend surface grind it for me, the bolt location teligraphed
> their position to the top of the plate.
> 3. Junk the entire table top. Buy a cheap x-y positioning table from J&L
> for a $100, throw away the base and
> attach it to the mill. Palmgren makes a marginal small table.
> Chinese imports are big, substantial and are
> cheap.
> 4. Work over or off to the side of the damage.
>
> The table is damaged because a dummy didn't know how to place a t-nut on
> the table and overtighted a
> bolt until it broke. T-slots can take a lot of punishment. It is unlikely
> that epoxy will hold however. The requirements
> for shear strength are way beyond what even a steel-laded epoxy can
> deliver.

Here's a bit more info on the table.

The hole goes thru the bottom of the table under the T's

Ascii Example.... |T T T T|
+=== ===+
^ Hole.

The hole ends just inside the vertical steel for the "T" at
the Front and back edges.
It is just over 2 inches wide.

The way I see it, the only thing that should ever load this part of
the table is the same bonehead stunt of turning a stud too far thru
Tee-nut.

I'll just make sure the Studs in all my Nuts will top out on the threads
before they extend out the bottom of the nut and prevent it from happening
again.

I want the top flush to enable easy cleaning, but don't think it needs to be
THAT strong.

It in no way should impact using part of the table, like breaking the top
off a tee or something.

The table is in the car to be checked for flatness tonight.

I do have a 1' X 5' slab of polished granite.
It isn't calibrated or anything but I'd bet it pretty damn flat.

I put it on the table, it plopped down with that "Thunk" I can't
quite describe that only comes from 2 very flat and smooth surfaces.

I'll see tonight with a REAL 8,000 lb surface plate.


The table is probably 300 Lbs, I about busted my ass getting it in
the car.

The hole also goes between the "thickeners" in the bottom of the
casting that go front to back.

My only real reason for fixing it would be to keep the crap from
falling down inside the machine, as it has for years.

I straightend the end of the leadscrew by hand to "Pretty Close"
I need to chuck it up in a big lathe tonight and use a dial to finish
the process down to a few thou.

I also need to fix some smashed threads on the end.

Marc