Chicago drill press

[gjz30075]

I just bought this table top drill press from an estate sale. Although made in Taiwan, it's heavy as he**. I think it was an ok deal at $45. As you can see its 12 speed and its currently on 2420rpm. I plan on using it mostly for metal drilling. I was wondering what speed should this thing be at for metal work? It'll go as slow as 260 rpm.

Greg Z

 

[lametec]

Depends on what metal and what size drill.

I just leave mine at the slowest speed.

 

[OctoMan]

It depends on the metal type and thickness, hardness, and drill bit size. Generally 700-1000 for steel, 2000 and above for aluminum. Follow link to article on the subject.

http://store.curiousinventor.com/guides/drill_speed/

 

[woody 73]

The slowest my old drill press will go is 750 which is what I use, since you can go lower that will be ideal; The above chart is a great starting place be sure and make a copy of it and place it next to your drill press.

 

[sgs236]

Each drill bit manufacture should specify a surface feet per minute (SFM) rating for a particular drill bit. The equation for RPM is RPM= (SFM * 3.82) / Drill diameter.

The machinists I work with give me the following "GENERAL" tips: If you are getting long spiral pieces of metal, then you are drilling too slow. If you are getting a lot of small tiny metal chips then your drilling too fast. It was also stressed to me that heat was in the chips, so small chips means your putting more heat in the drill bit - which reduces its lifespan.

 

[jtbinvalrico]

Speed down to 260rpm......5/8" chuck........$45.........I'd say you did pretty darned good on that deal.

 

[ez-duzit]

Have one of those I bought new for $99 many years ago. Works just fine.

 

[zkling]

It ain't the best machine out there, but for $45 you did good. It would always make a nice tapping machine in the future.

As for speeds, here are two basic formulas for twist drill bits.

Steel --> RPM = 285 / (dia of drill in inches)
ex. a 1/2" drill bit (0.500 in) would = ~ 500 RPM

Aluminum --> RPM = 760 / (dia of drill in inches)
ex. a 1/2" drill bit (0.500 in) would = ~ 1500 RPM

If you get chatter, you are feeding too slowly and or your workpiece is not secured properly.

 

[thinmac]

When in doubt, go slower. I usually go slower than the recommended speed. Those speeds are chosen for use in production shops, where throughput is more cost effective than preserving bits. For a small hobbiest shop shop you usually want to prioritize bit life over maximum productivity.

 

[gjz30075]

Great recommendations and a good article! Thanks guys.

Greg z