How do you drill on a CNC?

[777funk]

I'm drilling holes for mounting bridge parts and I have some 1/8", 3/16", and some 5/16" holes that I'd like to drill to around 1 and 3/4" depth. But how? I looked and all the 1/8" diameter spiral router bits are only 1/2" cutting length.

I thought about making drilling templates but I'd rather do it on the CNC if I can. Drill bushings and hand drills aren't the most accurate for me.

Probably a common problem but I have no idea how to solve it.

thanks in advance,
Nick

[wbegg]

My solution has always been to drill or pocket (depending on hole size and bit availability) as deep as I can, then finished up with my trusty old drill press.

I agree, it's a bit aggrevating not being able to insert a drill bit in a router (don't try it!) because of fast speeds. I've been working on a method of mounting a drill next to my router on the z axis, and setting up an offset so xy won't have to be reset.

Only other option I can think of is to buy a Spindle, which can be reduced to drill speeds for comon drill bits.

[Spinnetti]

Originally Posted by wbegg My solution has always been to drill or pocket (depending on hole size and bit availability) as deep as I can, then finished up with my trusty old drill press. I agree, it's a bit aggrevating not being able to insert a drill bit in a router (don't try it!) because of fast speeds. I've been working on a method of mounting a drill next to my router on the z axis, and setting up an offset so xy won't have to be reset. Only other option I can think of is to buy a Spindle, which can be reduced to drill speeds for comon drill bits.

2nd that.. just pilot drill on cnc, and use a drill or drill press after that... quick and easy. There are long drill bits however....

[tjskcnc]

1/8" ball nose bits from McMaster-Carr:
McMaster-Carr
These can easily drill 1.5" deep.
You can also use "peck" drilling, where the bit drills to a set increment, then pulls clear to a set height, then drills again to the set increment, until hole is complete.
I also have the local saw blade sharpening shop mill down 1/4" drill bits to the size I need. This way they fit nicely into a 1/4" collet and can be any length and thickness you need.
K2CNC sells brass adapters for 1/8" bits. Sears also sells a metal 1/8" adapter made of steel for less.

I do subcontract work for a large company using Fanucs, Bolos, and other large production multi-head machines. They cut at 600 inches a minute and drill at almost 300 inches a minute. They use simple straight 2 flute carbide bits for cutting and plain old drill bits for drilling.

[UUU]

I copy the procedure I use for hand drilling. Start with a centre drill to make a mark - bigger in CNC than I'd do by hand. You can move around and spot up several holes. Then in with an ordinary drill, following the same X,Y coordinates, with adjustment in Z for the increased length - as long as it's not bent it seems to pick up the mark.

[RomanLini]

Originally Posted by wbegg ... I agree, it's a bit aggrevating not being able to insert a drill bit in a router (don't try it!) because of fast speeds. I've been working on a method of mounting a drill next to my router on the z axis, and setting up an offset so xy won't have to be reset. ...

One of the reasons I designed the SuperPID router speed controller was to do drilling. It allows drilling as low as 5000 RPM still with good torque, on any router.

There's a thread on the SuperPID here.

And there is a Youtuibe of my machine with router drilling 1/8" holes at 5000 RPM [B]here.[/"]YouTube - Super-PID drilling acrylic at 5000 RPM
It also gives you the ability (at low RPM) to cut fussy materials that have low melt points like many decorative plastics. I'm not a wood guy but I do regularly cut some fussy plastics for engineering and robotcs applications etc.

[luthier]

I use dremel tool bits in a 1/4-1/8 adapter that I bought at sears a few years ago.

[CarveOne]

Originally Posted by RomanLini One of the reasons I designed the SuperPID router speed controller was to do drilling. It allows drilling as low as 5000 RPM still with good torque, on any router. There's a thread on the SuperPID here. And there is a Youtuibe of my machine with router drilling 1/8" holes at 5000 RPM [B]here.[/"]YouTube - Super-PID drilling acrylic at 5000 RPM It also gives you the ability (at low RPM) to cut fussy materials that have low melt points like many decorative plastics. I'm not a wood guy but I do regularly cut some fussy plastics for engineering and robotcs applications etc.

At 5k rpm a standard RotoZip bit that has the sharpened tip would be long enough and may not have unacceptable run-out for drilling and opening up holes larger than the bit. They are worth trying, and will make relatively flat bottomed blind holes. Cheap enough anyway.

CarveOne

[ger21]

Here's another video of 5000 rpm drilling with a Super PID controlled router.

YouTube - Super-PID Drilling Test