Drillin' dem holes

[Ron Earp]

I'm drilling lots of holes to catch up with my panel mounting. I fit most of mine and then used a lot of clamps to hold them in place. Now I'm final fitting and drilling holes to use clecos.

However, I'm going through some bits at a serious rate. I got some of these cool double ended bits from McMaster Carr but they don't last for *!&%. Yes, I'm using fluid. But, I think I only got though about 20 holes or so before I noticed a serious decrease in drilling rate.

Anyone have any info on high quality bits that last a good while?

Ron

Hello Ron,
They are very expensive but last for a long time - carbide tipped drill bits, you will only find them at industrial supply houses like McMaster-Carr or WWGraingers. A little less expensive are cobalt drill bits although they don't last quite as long as carbide tipped bits but longer than regular high speed steel drill bits. As for your regular high speed drill bits you can re-sharpen them yourself. It takes a little practice and knowing the correct angles to grind but once you get it figured out its a great time saver and easy on the wallet. A standard bench mounted grinding wheel and any edition of the 'Machinists Manual' (McMaster-Carr should have this for about 20 or 30 bucks) this will tell you the correct angles to re-grind your bits. When you get good at this you will find you can put a better cutting surface than you bought them with. Also keep a cup of water near the bench grinder, to periodically dip the bit into to cool it and keep its hardness, if it cools by air on its own it will self anneal, you don't want to make it softer. Hope this helps.

Best Regards,
John Hester

[ October 17, 2001: Message edited by: John Hester ]

[Chris Melia]

Hi Ron

dip the drill tip into a light oil for each hole.
For alloy use parafin.
Chris Melia

PS did you get the E_mail fhotos of GTD AGM?

Ron, Avery aircraft sold me some bits that last forever. I told him I was drilling about a 1000 holes and he told me I would need two. I am still using the first one and I am almost done drilling. They have a web site and will ship them to you. I never used any oil them either. I am in Oregon this week and can give you the part number when I get home.

SO BOB'S IN OREGON THIS WEEK. I KNEW MY SHOP HAD BEEN AWFUL QUIET AND NOW I KNOW WHY. [img]images/icons/wink.gif[/img] [img]images/icons/wink.gif[/img] [img]images/icons/wink.gif[/img]

I DID LEARN RECENTLY THAT TO MAKE SOME BITS LAST LONGER, REDUCE THE TURNING SPEED AND USE CANOLA OIL ON THE TIP. I'M REALLY NOT KIDDING ABOUT THIS. IT DOES WORK WELL.

JAY


OH I FORGOT, GET A DRILLBIT SHARPENER FROM NORTHERN FREIGHT OR THE LIKES. WELL WORTH THE 20-30 BUCKS.

[ October 18, 2001: Message edited by: jayscobras ]

[Hershal Byrd]

Here is the Avery aircraft site Bob refered
to. http://coldfusion.averytools.com
You will have to click onto the aircraft tools kits then select the RV-9 kit. all the bits are there. Weird but thats the way they have it.
I use these bits as well. They are Cobalt and
last a long time, I know cause I am drilling stainless. I haven't put any oils on them either. I did break one but it was due to a sharpe drilling angle. [img]images/icons/grin.gif[/img]
If you need them right away you can check the Yellow pages in your area for an aircraft supply. They always have these bits.

Hersh [img]images/icons/smile.gif[/img]

Ron,

Typically, carbide drill bits are used for softer materials in situations where the bit will not be torqued. They don't like that at all!

Cobalt drill bits are a good compromise between HSS and Carbide and are good for harder materials.

Running the drill bit at a slightly slower speed and using a cutting oil will usually make them last about 10 times as long.

No drill bit will last forever though. If you have a significant investment in a shop, I suggest the Drill Doctor sharpener. It uses a diamond wheel and the larger one (abt $160) will do 118 degree, 135 degree and split point drill bits. Can easily pay for itself over time. (I hate to chuck 1/2" and larger USA made drill bits ... that hurts my penury!)