Flywheel

[blackfoxsteam]

Before I ruin this flywheel trying to drill five more 0.5" holes, can someone advise the best way to do it? My tools are a Delta drill press and a 6" Craftsman/Atlas lathe with milling attachment.

 

[rhitee93]

It looks like you already have them located which is the hard part. Given your tool list, I'd be using the drill press.

Did you have some trouble drilling the one you already did? If so, tell us what happened, and maybe we can go from there.

 

[blackfoxsteam]

I mounted the flywheel on a board clamped to my rotary table on the drill press; there was a 1/4" wood dowel through the center and a 1/8" drill bit through a 1/8" hole in the flywheel to stabilize it. I went straight to a 1/2" bit which chattered badly and, upon breaking through, lifted the flywheel to the top of the 6" long bit. I tried a 1/2" 4 flute end milling bit on a piece of scrap and it just wallowed around as it moved the table around.

 

[rleete]

Use a smaller drill to start, and work your way up. It's called step drilling.

 

[chucketn]

Step drilling as suggested by rleete is the key, the more steps the better. I would add that locking the rotary table for each hole will help also. I just made a similar flywheel on my RT on my mill. My first like that. Piece of cake, as they say...

Chuck

edit to add rleet

 

[sampie]

The cutting edge in bronze must be 0 degrees

Bernie

 

[Gedeon Spilett]

"I went straight to a 1/2" bit which chattered badly and, upon breaking through, lifted the flywheel to the top of the 6" long bit"

large drill bits often do that in brass or bronze, it could be pretty dangerous. you have to set cutting angle to 0° with a stone. most probably, yours drill bit (twist drill) is now twisted after that, roll it on a surface plate to check.

 

[rhitee93]

The other issue you faced is that most 4-flute endmills do not plunge cut well.

Like others have said, clamp it down well, and step drill it. I am not a fan of step drilling because it always seems to chatter more. However you already have a small hole started so your best bet is to step up in small increments from where you are at.

 

[devitg]

I want to give an old trick , it was the first trick I learn on my first job as a paid for work.
I had my mechanic technical school degree , at my 21 years old in 1970, it should be at 18 but I lost 3 years.
Well , following the history , my shop teachers where former employee at the plant where I where working, I have to re drill a big press die base to suit new parts as the model was changed , I nee to drill a 2" diameter , as teach I did a small , maybe 0,5" , then 1" and after it the 2" drill, just when I star it begin to whirl , and a old man , former work mate of my teacher, say in loud voice.
"HEY, DID NOT YOUR TEACHER TO USE A FOLDED FABRIC or CLOTH , BETWEEN THE DRILL AN THE PIECE" , no, I said and it show me to put at least about a 1" thick of piece of fabric layers or cloth between the drill and the piece, and magic , it make a perfect drill like it was reamed.
For smaller diameters , 4 layers is enough, emery cloth can be used too , old leather from gloves also.
The fact is to fill the flutes.
I use it since that time , when I want to have a "perfect" hole.
Of course it need more power to drill, and is the best choose to make a hole on a thin piece of metal.

 

[DanP]

If I understand you, the idea is to put a layer of fabric down on the piece of metal you're drilling and then drill through it, into and through the piece of metal. Is this what you're saying?

 

[skyline1]

Is this flywheel brass or bronze. If it is brass it shouldn't be too much trouble but step drilling is a good idea going straight in with a 1/2" drill is likely to cause chatter unless your whole setup is very rigid.

Bronze is notorious for "grabbing" drills and reamers and step drilling is a must.

Also what speed were you drilling at Brass can be drilled at quite high speeds but I have found that bronze needs to be done more slowly, With a drill as large as 1/2" I suggest as slow as your drill can go and drilling very gently lifting the drill often to clear it.

Bronze also needs to be firmly clamped, When I was much younger I threw a bronze casting clean off the drilling machine and across the workshop when the drill snatched and it wasn't clamped well enough. Luckily no-one was hurt but it could have been very dangerous.

I hope some of this will help you and I haven't alarmed you too much but you do need to be cautious when drilling bronze

Regards Mark

 

[gus]

Here's how I do it. Brass and bronze has a habit of grabbing the drill and lift the job and swing it all over to hit some poor guy's head. I have seen during my apprentice days. Drilling brass plates & sheets with incorrect drill point and no clamping down, can lift off and cut some poor guy's abdomen.I saw a near accident.

Clamp down the piece to drill press table. Use the stop screw to advance drill bit by bit.This way will not grabbing will happen.

 

[devitg]

If I understand you, the idea is to put a layer of fabric down on the piece of metal you're drilling and then drill through it, into and through the piece of metal. Is this what you're saying?

Not 1 layer , 4 at least , the best I use, is JEAN fabric.

Yes , that´s the trick , of course you have to fix the piece to the drill table

 

[blackfoxsteam]

Thanks to everyone for the assistance on drilling the 4" brass flywheel. I used step-drilling (9 steps) as recommended after SECURELY mounting the wheel to the X-Y-rotary table and used two hands on the spindle handles to limit bit grabbing. It worked fine, thanks.

I'm not familiar with 0 degree drill bits, are they available or do you file your own?