# An eye opener for me - Lathe drilling with short bits



## Texatdurango (Feb 27, 2010)

It is widely accepted that using a center drill is the most accurate way of drilling a starter hole in a blank to be followed by a larger drill. The reason the center drill is so accurate is that it is short and rigid with no flutes so it doesn't wander around when drilling end grain. 

I was browsing through a tooling catalog recently and a set of drills caught my eye, they are called “Screw Machine” drills and they differ from the traditional “Jobber” drills in that they are about half as long!

Since I do all my drilling on the lathe and with some bits protruding almost 5” beyond the drill chuck, I was intrigued with the idea of having a shorter, more rigid drill to not only drill my starter holes but the final holes as well.

I ordered a set of the machine drills, tried several sizes out drilling wood, acrylic and truestone blanks and immediately noticed a big difference, the occasional “chatter” or “drift” was gone. Nothing but nice quiet drilling!

I don't own stock in any tool company, am not selling bits, and am not advocating anyone running out and buying a set of these bits but if you are experiencing the occasional “bit wobble” where you have to hold onto the drill chuck for dear life, then perhaps you might consider trying one of these shorter bits.

Most of the blank drilling I do is on blanks around 2” give or take a few tenths and all of the drill bits I bought are capable of drilling holes that deep. Google "machine drills" and you'll see lots of suppliers who carry the drills.

*Just something to think about!*

They say a picture is worth a thousand words so to keep from typing all night, here are a few shots I took:

Here is a typical center drill, note the short length.







Here are the same size drills in "screw machine" and "jobber" lengths






Here is a handful of screw machine drills and jobber drills they replaced







Here is what I see when drilling with a jobber drill, note the total length! That's almost 5" of bit sticking out to drill a 2" hole.






Here is what I see when when using a screw machine drill, almost as short as a center drill... and just as rigid!


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## mick (Feb 28, 2010)

Great info George! I've thought about shorting some of my bits to jobber length. Since I have a Drill Doctor resharpening them shouldn't be a problem after shaping them on a grinder. The only thing holding me back is not being sure of the best way to cut them down....I don't want to overheat them and ruin the temper. Any suggestions.....or should I bite the bullet and just buy jobber bits as I replace certain bits?


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## low_48 (Feb 28, 2010)

I've cut down quite a few drill bits with my Dremel. I use the fiber reinforced wheels, not the cheap little brittle discs. Not much pressure, and a little water keeps them cool.


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## PaulDoug (Feb 28, 2010)

I have always used brad point bits.  Never had any problem.


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## RDH79 (Feb 28, 2010)

George, Great Info. Can you shot me a PM where you got the bits if you dont want to post it.   I tried to drill on the lathe but always get the chatter. This will help.. Thanks

Rich


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## Jim15 (Feb 28, 2010)

Thanks for the info. George.


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## randyrls (Feb 28, 2010)

These style bits are available from both MSC and McMaster-Carr

MSC:  http://www1.mscdirect.com/cgi/nnsrhm

McMaster-Carr: http://www.mcmaster.com/#


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## randyrls (Feb 28, 2010)

mick said:


> Great info George! I've thought about shorting some of my bits to jobber length. Since I have a Drill Doctor resharpening them shouldn't be a problem after shaping them on a grinder. The only thing holding me back is not being sure of the best way to cut them down....I don't want to overheat them and ruin the temper. Any suggestions.....or should I bite the bullet and just buy jobber bits as I replace certain bits?



Mike;  You want "machine screw" length.  

You can shorten large drill bits, I have done this.  I cut the rough angles using a cutoff wheel and side grinder.  I then shaped the angles on a grinder and then finished with the drill doctor.  One down side is that drill bits change cross section and get thicker as you go toward the shank end.


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## Lenny (Feb 28, 2010)

Great post George, Thanks!


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## jeffnreno (Feb 28, 2010)

Thanks George - Your always are coming up with something new and better for pen turning.


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## Texatdurango (Feb 28, 2010)

RDH79 said:


> George, Great Info. Can you shot me a PM where you got the bits if you dont want to post it. I tried to drill on the lathe but always get the chatter. This will help.. Thanks
> 
> Rich


 
I looked around for "Made in America" drills thinking they would be better quality and bought my set here... http://www.discount-tools.com/mic-drillset25.cfm , I got the 135 degree split point set for $71

I didn't check with Little Machine Shop until after I ordered but they also carry basically the same American made set for $75... http://www.littlemachineshop.com/products/product_view.php?ProductID=2830&category=-456343308


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## Texatdurango (Feb 28, 2010)

jeffnreno said:


> Thanks George - Your always are coming up with something new and better for pen turning.


 
I don't know about the "new and better" but I usually have a smile on my face when I'm in my shop.  I don't know if it's from the CA and lacquer fumes or because I'm just enjoying my hobby and finding little ways to make life a little more enjoyable and more convenient! 

At our monthly turning club meeting last week, the demonstrator talked about his life as a wood turner and how things have changed over the years.  He is 93 now, and when he started turning, he made all of his own cutting tools and had to come up with his own ideas on how to perform tasks so the creativity juices were always flowing.  Like him, I always try to imagine a better or easier way of doing something rather than just doing what everyone else does then calling it a day.


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## RDH79 (Feb 28, 2010)

Texatdurango said:


> I looked around for "Made in America" drills thinking they would be better quality and bought my set here... http://www.discount-tools.com/mic-drillset25.cfm , I got the 135 degree split point set for $71
> 
> I didn't check with Little Machine Shop until after I ordered but they also carry basically the same American made set for $75... http://www.littlemachineshop.com/products/product_view.php?ProductID=2830&category=-456343308



Thanks George, I will check out the sites. My drill press even though its brand new (CRAPSMAN) is not the best at drilling the bigger sizes. I think this will do to trick.   
Thanks Again

Rich H.


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## DurocShark (Feb 28, 2010)

Do you use the center bit still with the machine length bits?


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## bitshird (Feb 28, 2010)

OK what about the Metric drills like the 10.5, 12.5 and 13.3 also what about the few alpha and numerical? I use Machine length drills all the time on mill and lathe drilling, but there's a lot of sizes we need that I haven't found,


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## lorbay (Feb 28, 2010)

Good advice George. Thanks.

Lin.


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