Stiffest Drill Bits?

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MisterMan
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Stiffest Drill Bits?

Post by MisterMan » Fri Feb 10, 2006 8:07 pm

Are some #44 drill bits stiffer than others? If so, what are the stiffest, and more importantly, where can they be bought?



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Stan Pope
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Re: Stiffest Drill Bits?

Post by Stan Pope » Fri Feb 10, 2006 8:35 pm

Here's a post that answers ... Other's also came up with search for "stubby".

http://derbytalk.com/viewtopic.php?t=66 ... ght=stubby


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Re: Stiffest Drill Bits?

Post by ExtremePWD » Fri Feb 10, 2006 8:59 pm

I have used a straight flute #44 which is stiffer than a standard HSS #44. The next level hardness would be cobalt drills. Way out on the hardness scale would be solid carbide drills. Typing "cobalt drills" or "solid carbide drills" into Google will bring up sources. Cobalt drills should be under $2. Solid carbide might be closer to $10. In either case, small order shipping usually is relatively high.



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Re: Stiffest Drill Bits?

Post by ExtremePWD » Sun Feb 12, 2006 5:44 am

There are some #44 solid carbide drills on ebay. Search on "44 solid carbide drill". Just bought 2. I'll sell the spare locally to recoup some of the shipping cost.



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Byiani
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Re: Stiffest Drill Bits?

Post by Byiani » Thu Jul 26, 2018 12:18 am

I sorry for bump an old topic I just have a few interesting observations from personal experience, maybe someone will need this information in the future. Stainless is already pretty hard and as it heats up it will work-harden even more. Hal has it right, go to a real industrial/machine supply house and buy some good quality HSS/Carbide twisted drill bits. If this is a one-time thing then don't bother getting coated bits. The coating is primarily to help the longevity of the bit, not really to ease or help the drilling process itself. If you plan to use this drill a lot then an AlTiN coating works well on extremely hard metals (steels, stainless, high-carbon, etc).

I would probably use a 1/8, then 1/4, then 3/8, then 1/2" to get the desired hole. You could also stop at 3/8 if you wanted to use the punch listed earlier in this thread. The smaller bits you can spin faster (200-ish RPM's), then slow down as you drill bigger (100-ish RPM's). The trick here is to limit the linear speed of the cutting surfaces so as to not work-harden the stainless (overheat). Ask the supply house for a drilling fluid that isn't runny and put a quarter-sized blob over the cutting area. When one-bit drills through it, change the bit then wipe the new bit down with cutting fluid using a rag. If the steel scarf (shavings) start to turn blue as you are drilling then you are going too fast and should slow down. The stainless you are drilling is thin and will heat up quickly if you aren't careful. If you do blue the stainless then stop, let everything cool down (bit included), re-oil, and SLOWLY drill past the blue.

The last thing I want to mention is to not break these cobalt bits https://mechanicguides.com/best-cobalt-drill-bit-sets/ while drilling. Unlike the cheaper bits these do not flex. What they will do instead is shatter if you use too much force or dont hold the drill steady.

Hope that helps!



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Re: Stiffest Drill Bits?

Post by gpraceman » Thu Jul 26, 2018 10:06 am

@Byiana - For building these cars, we are only drilling into wood, to make holes for the axles to go into. The idea of using stiff drill bits is to keep the bit from following the grain lines, going off the desired drill line.


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whodathunkit
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Stiffest Drill Bits?

Post by whodathunkit » Sat Aug 04, 2018 8:46 am

Not to go off topic about drill bits here!

But to share something that works for drilling
Hardened steel like an broken off ez out tool in a bolt.

Tried several different types and makes of drill bits to re drill into the ez out. The drill bits just would not cut in to it.

So I broke out a masonry drill bit
Used Constant pressure and drilled with a slow speed
And was able to drill threw the ez out tool that had broke off in the bolt.
It was slow going and the shavings were more of a powder instead of shavings.

Any how just thought I’d share something that worked for drilling into the hardened steel
ez out tool that had snapped off.




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