Drill Press keeps stalling, what's the problem?

[James_Terrio]

I'd definitely recommend a dark "sulfurized" cutting oil when drilling stainless, but for carbon steels, any handy oil is fine.

Can you explain what the advantage is? When I bought my (admittedly cheap) drill press last fall, I got a small jug of GUNK brand "dark, sulfurized-chlorinated" cutting oil. I use a little pointy-tipped squeeze bottle to apply it to the bit before I drill and keep the bit/hole "wet" as I go. It does seem to work quite well. My bits (also not the best on the market) cut true and stay sharp longer than I thought they would. I'm just curious why it works so well. Does the sulfur and chlorine help with lubrication, heat-transfer, or both?

Incidentally I have used the same press/bits/oil on various high-carbon, tool and stainless steels. Works good on all of them. I have my press running as slow as it will go (620 according to the manual, which still seems a bit fast). I put the steel in a machinist's vice, make sure everything's level and square, and clamp the vise to the table. I feed the bit into the steel pretty slow and back off when the swarf starts to curl up along the bit and spin around. I'm getting good results but I always wonder if I'm missing something... any other tips on proper use of a drill press would be appreciated.

Thanks gents!

 

[DocsMachine]

The sulfur acts as a high-pressure, high-temperature lubricant. Sulfur melts at a higher temp than what will make the oil vaporize, so if the cutting faces are getting hot enough the oil wants to boil away (we're talking on a near-microscopic scale, right at the cutting edge) the sulfur remains and provides the lubricating action.

That's a simplified and generalized explanation, but you get the idea.

As for the cutting speed, you don't want to go too slow- as in, how hard you feed in the bit. If you let the bit "dwell"- turn in contact with the work, but not cutting- you'll both wipe the cutting edge of the drill and possibly work-harden the hole.

You want to get the bit cutting, applying reasonable force but not leaning on the handle, back off and apply lube, the get back in there and cut again. There's a "feel" to it, just as there is to how well a certain belt is cutting. It might be worth your time to get a few new bits and a chunk of scrap steel, and play around.

Try pushing harder than you usually do, try and really mash that bit in there. You might be surprised how well it cuts... assuming the press can take it, and that's iffy with a cheap import.

That "1/3rd HP" motor? You'll be lucky indeed if it actually gives you a full one-sixth horse. We put an amp gage on one once- a no name "tool sale special"- and tried to bury a 3/4" bit in a chunk of hardwood. It was ridiculously easy to stall, and calculating from the max amp draw, the motor was giving us barely one-eighth horse.

Doc.

 

[WDZ Knives]

Also see if you can find a machine shop supply in the area. It's been cheaper for me to buy bits there than at a hardware store and the bits were better.