Drill Press Table Issues

[Corvus corax]

I have a little Einhell 701/1 Drill press. 85cm high, 650 Watt motor, 12 speeds.
www.hubhong.com/Einhell/Bench-Drill/SB-701.pdf
Sorry that's the only English specs I can find for the thing. It's a PDF document.

The column itself is actually fairly rigid but the table is terrible. With a dial indicator set to sweep from the chuck I get about 0.6mm flex by pressing hard on the front of the table with my hand. You can actually see it flex during drilling.
Anyone got any ideas for making these tables more rigid?

I thought of some kind of screw jack foot type thing.

The table can be canted left and right but it's a bit out front to back. I was going to shim it but then I recalled some of the bigger presses that I used to work on had a grub screw for doing this. Sorta like this:
http://home.vicnet.net.au/~pwguild/i-dp-adj.htm
Anyone ever tried doing something like this afterwards as a levelling aid.

[Anzaniste]

I have the same problem. I use a vintage car screw jack, seems to work well but is a bit of a pain in the rear,

[andyf]

It appears from the specs that the quill movement is 60mm. I wouldn't be surprised if, for most jobs, the table is set within a fairly restricted height range If that's the case, maybe you could make two or three pillars of different lengths to stand on the front of the base, and lower the table on to the appropriate one for the job in hand. For the average job, that might be quicker than adjusting a jack.

Andy

[Anzaniste]

An supposeedy, you are dead right. I dont often adjust he jack.
Why didn't I think of the simple aproach? ('cos the jack was to hand I suppose )

[Corvus corax]

At the minute I'm thinking of two pillars,one on each front corner, with some kind of jacking screw for levelling adjustments.
A few of these ijn different sizes should work as described above.

[Bryan]

If it were me I would be trying to isolate where the flex is occurring to see if I could fix the actual problem. It may be a poor fit at the table mount that could be re-machined, or shimmed. If the table itself is flexing, maybe you could bolt a steel rib to the underside?

[Corvus corax]

So, I took the table off to see what I was dealing with.
Here you can see the male section on the actual press where the table fits.

The corresponding piece at the back of the table

There were no immediately noted imperfections that would be causing that much flex.
As can be seen, the part of the table, at the back where it attaches to the press is very thin. Only 17mm thick. 9.5mm of which is recessed for the corresponding male fitting on the press.

The table itself viewed from the top

The table viewed from the bottom

This is, IMO, where the actual problem is, the table surface is only 4.5mm thick, the areas that are reinforced by those struts in the casting are 10.8mm thick.

I could try adding some 15mm thick x 50mm wide braces front to back on the table. Either epoxying them in or drilling through and bolting them down. However, I think there is no way I will be getting round the support columns up front.

[Bogstandard]

By the looks of it, your problem seems to be the central boss, sticking out from the upright casting (picture 1).

Measure how much the boss is sticking out and how deep the recess in the table is that it fits into. The large round machined face on the table itself, should be butting up to the surface around that central boss, and making everything stable. I reckon that the boss should be about 2mm shorter than the hole it fits into is deep. So if the hole depth is 10mm, boss height should be about 8mm, to allow those large bearing faces to be tightened up to meet each other.

Or the cast upright bearing face is so far out of wack, the table can wobble about. If that is the case, the upright bearing face must be machined up square


Bogs

[Corvus corax]

Before I go any further let me thanks to everyone for looking and helping. It's a great group.

Bogs, I measured the boss  (Thats the word, I've been living here so long, I'm loosing my English) there are just under 2mm of clearance I get 7.6mm on the extension and as I said above, the recess is 9.5mm.
I decided to check the bearing surfaces, lacking any real Prussian Blue I had to make do with the Ghetto version and used a marker pen. Slathered it on thick on the table, mated the two parts and snugged up the bolt.

These were the results
The table. You can just see where the marker rubbed off

The boss itself. The marker is visible on some of the outer edges It is obviously slightly concave but the bearing surface may be less than optimal.

I would happily face the thing off, if I could figure out how to get that casting onto my 9x20

[sparky961]

I've attached a PDF file showing my recent solution to the same problem.  I "upgraded" my older smaller drill press for a newer and slightly bigger one branded as Mastercraft (Canadian Tire).  I was happy with everything except the 1/4" of deflection when I applied light drilling pressure.

Maybe that's a safety feature?  Break the table off before you strip the gears?

My new table doesn't deflect, period.  It retains the pivoting as the original, and I replaced the slots that I never use with tapped holes for hold down clamps.  4 of the holes are placed for bolts that hold my drill press vice.

The pieces are plasma cut and welded.  It shouldn't be too hard to find a place that will cut a handful of parts for a handful of cash.

Drop me a line if you find it useful.

-Sparky

[Corvus corax]

That's a nice table design!
Something like that combined with an XY vice would be fantastic.

I was at the steel merchant yesterday to get some 22mm round bar to make a couple of different length support columns. This will have to do for the while since I need the stupid thing to drill holes while my mill is set up for something else.

The guy at the steel merchant's counter says steel prices should come down again in a few weeks. Hopefully that will make the table idea a bit more affordable. I will also have a look at the scrap yard to see what is scrounge-able.

Oh dear another project on the list

[sparky961]

I should also mention that the boss was machined after welding in order to keep everything nice and square.  I used a boring head on my mill and clamped the table to an angle block.  In hindsight, it would have been quicker to rough the boss on a rotary table or lathe/faceplate (hmm... safety concern?) and then a light finish cut after welding.  It took a long time with the boring head, but I'm happy with how it turned out.

The drawing I posted isn't completely dimensioned because I just needed a quickie for assembly and machining.  Everything else was "derived from CAD", as they say.  Most people would likely want to customize the dimensions and hole layout, but if anyone is interested in other dimensions or solid models just ask.

-Sparky

[Corvus corax]

Well today I needed to use the drill press since my mill was setup up with another project.

I had made the aforementioned support columns so I quickly decided to level the table. Whilst doing this, I noted some other rather "interesting" readings on my Dial indicator.
The result of which was that I took the table off and checked it on my granite surface plate.
Yep you all guessed it, not only does the stupid thing flex, it's also warped!
I gather the casting didn't undergo any stress reliving and this was the result.

The surface is so bad that I could probably have done better by offhand skimming the thing with an angle grinder fitted with an abrasive disc.

This leaves me with a few options.
Take the thing to a machine shop and get it resurfaced. Not even sure where to start looking around here.
Make a sub-table of some kind and level it with shims
Level a cheap X Y Vice with shims
Curse the thing and take it to the rifle range where at least it would see some good use as a "gong"
Bite the bullet and just make sparky's table.