# Best type and brand of screw machine drills:



## ome (Sep 29, 2013)

Hi guys,
Another question about the best type of drill, the point, as well as bright vs black oxide.
I will be working with alum< steel<stainless, but to begin with mostly aluminum.
I have a cheap 3 in 1 set from 1/16 - 1/2 in 64's, cost me about 40. even came in a metal box and organised.
I have checked enco and they sell Hertel, and M.A. ford, single and in 3 in 1 sets going up as high as 600.
any info would be appreciated
Thanks,
jon


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## mikey (Sep 29, 2013)

I like the bright 118 degree Precision Twist Drill 115 piece set screw machine set. I think most of the brand name sets will serve you well - PTD, Triumph, Chicago Latrobe, etc but they are pricey. I suggest watching for a deal on ebay unless you're well heeled and can afford retail.


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## Gerritt (Sep 29, 2013)

I have been buying individual stub drills from KBC Tools. They have several quality grades, so far very happy with thier own brand. Some of the own brand drills are made in USA, some elsewhere. They drill very well in T6061, e.g. a 12.5mm hole with no pilot and no centre punch doesn't wander.

KBC has locations in US as well as Canada so shipping isn't the usual cross border expense.

Gerrit


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## Mid Day Machining (Sep 29, 2013)

ome said:


> Hi guys,
> Another question about the best type of drill, the point, as well as bright vs black oxide.
> I will be working with alum< steel<stainless, but="" to="" begin="" with="" mostly="" aluminum.
> I have a cheap 3 in 1 set from 1/16 - 1/2 in 64's, cost me about 40. even came in a metal box and organised.
> ...



Enco will tell you Hertel or M.A. Ford drills are the best because that's what they sell. If you ask MSC, they will sell a different brand and that will be the best.

A good set of drills however is not going to be cheap.

What to buy depends on what you plan on doing with them. I make a couple of parts that require me to drill a 1/8 inch diameter hole on a piece of 3/16 thick 7075 aluminum that if 4 1/2 inches deep. I spent a lot of time and money learning how to do this and now I can drill that hole straight within less than .002. I know it's straight because I will take one part about every 50 to 100 pieces and cut the bottom off just to measure the hole.

When you buy your drills, get a X750 Drill Doctor as well, then you can maintain your drill points.

</stainless,>


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## lrsglory (Sep 29, 2013)

Just an opinion. Its real easy to try to over think twist drills. Please consider this. Unless you are running production drilling applications , in a specified material. On piece work or production run. The 118 deg. common drill works great. Many centuries ago I purchased a set of National Cobalt HSS drills, used them in every shop I ever worked in, every material I ever drilled. Worked great, keep in mind this was just one to ten pieces. Some holes in each one. etc. More holes, sharpen more often. I dare say most experienced machinists out there could can do just as well in these applications with the std. 118 deg. drills as some one devoting too much time to the perfect grind for a certain material. A hole is a hole. If it has to be perfect, ream or bore it. Unless you have more money than you need, its america. I would recommend Cobalt HSS. Tougher than the skin on a T-Rex. Like anything in metal removing. Rigidity, and surface speed feet per minute. The material dictates the speed at which it will allow itself to be machined. Stay within its guidelines and you should be ok. For what its worth. I worked in a shop decades ago, setting up and keeping running a pair of Snow Automatic drilling machines. material was sintered powder metal parts of a certain RC. Don't remember.It was tough stuff though.  Two holes in each part, 5/16 dia. After some weeks of testing varous drills and drill angles, The best performer was a cobalt HSS drill with a 118 Deg. splt point. We split the point, ( reduced the length of the chisel point ) by hand. With practice every one got real good at it. Result. Material thickness was about 3/8 inch. Those machines would blow that hole in the part in about 4 seconds. Average life of drill 1000 pcs. Definitely worth the time spent experimenting.


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## davidh (Sep 29, 2013)

shameless plug again. I have been supplying ALFA USA made stub drills to guys on this and a couple other forums for $57  for a 29 pc set in a nice metal index box.   split point - 135 degree .  delivered to your mail box.
all seem to be satisfied with the product AND price.  
send me a private email if your interested.  
USA only or I think the freight will be way too high.


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## cazclocker (Sep 29, 2013)

I just read this thread and I think geometry needs to be mentioned. So far, davidh was the only one to mention 135-degree split-point geometry. I'm not an expert at all but the way I had it explained to me, is that 135-degree point angle gets the drillbit's full diameter into the metal sooner than 118-degree angle. Also (and more importantly) the split-point tip geometry helps to prevent "walking" on the surface of the metal way better than chisel-point geometry.


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## ome (Sep 29, 2013)

Mid Day Machining said:


> Enco will tell you Hertel or M.A. Ford drills are the best because that's what they sell. If you ask MSC, they will sell a different brand and that will be the best.
> 
> A good set of drills however is not going to be cheap.
> 
> ...


i am assuming a drill doctor works easier and faster than using a import universal tool and cutter grinder with an attachment for twist drills?
jon

- - - Updated - - -



gerritv said:


> I have been buying individual stub drills from KBC Tools. They have several quality grades, so far very happy with thier own brand. Some of the own brand drills are made in USA, some elsewhere. They drill very well in T6061, e.g. a 12.5mm hole with no pilot and no centre punch doesn't wander.
> 
> KBC has locations in US as well as Canada so shipping isn't the usual cross border expense.
> 
> Gerrit


Thanks , what was the point 118 or 135? Just hss or cobalt?

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cazclocker said:


> I just read this thread and I think geometry needs to be mentioned. So far, davidh was the only one to mention 135-degree split-point geometry. I'm not an expert at all but the way I had it explained to me, is that 135-degree point angle gets the drillbit's full diameter into the metal sooner than 118-degree angle. Also (and more importantly) the split-point tip geometry helps to prevent "walking" on the surface of the metal way better than chisel-point geometry.


Thanks, so am i better off going with set of stub drills  with a 118 or 135 point?


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## lrsglory (Sep 29, 2013)

cazclocker said:


> I just read this thread and I think geometry needs to be mentioned. So far, davidh was the only one to mention 135-degree split-point geometry. I'm not an expert at all but the way I had it explained to me, is that 135-degree point angle gets the drillbit's full diameter into the metal sooner than 118-degree angle. Also (and more importantly) the split-point tip geometry helps to prevent "walking" on the surface of the metal way better than chisel-point geometry.



Just an edit here. I don't think I ever put a hole in anything unless I center drilled it first. Sorta an SOP. No one, myself included , can or should minimize the importance of specialized included angles suitable for various materials. The 135 deg. split point is a very effective drill geometry. My point only being that for the average folks, drilling only a few holes, is the expense and effort worthwhile. Even the machinery 24th edition recommends 118 deg common, high strength steels 118 to 135, aluminum alloys 90 to 140 deg., magnesium alloys 70 to 118 degs. For what its worth.


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## cazclocker (Sep 29, 2013)

ome said:


> Thanks, so am i better off going with set of stub drills  with a 118 or 135 point?



I would say 135-degree point angle, split-point, in stub length (aka "screw machine length"). The stub length gives more rigidity (stiffness) to the drill bit, more than the lengthier "jobber's length" drill bits. The split-point helps prevent "walking" when the point first meets the metal's surface. And the 135-degree point angle simply lets the drill diameter become fully involved in the holemaking process a few thousandths sooner. That's just my opinion. lrsglory has an excellent point, about centerdrilling a hole with a center drill prior to drilling your final hole.


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## ome (Sep 30, 2013)

cazclocker said:


> I would say 135-degree point angle, split-point, in stub length (aka "screw machine length"). The stub length gives more rigidity (stiffness) to the drill bit, more than the lengthier "jobber's length" drill bits. The split-point helps prevent "walking" when the point first meets the metal's surface. And the 135-degree point angle simply lets the drill diameter become fully involved in the holemaking process a few thousandths sooner. That's just my opinion. lrsglory has an excellent point, about centerdrilling a hole with a center drill prior to drilling your final hole.


Thanks Doug,
took your advice and got decent deal on 115 piece stub cobalt 135-degree split point with case.
Regards,
jon


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