# Lets Get Basic- Drill Bits For Lathing



## Swerdk (Oct 7, 2015)

Is there bits or certain companies worth buying from? What is the difference between jobber and " Silver & Deming" bits?

Don't want garbage bits - where to buy, brand name, type of bit?


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## scsmith42 (Oct 8, 2015)

I like Greenfield and Magnum bits from Norseman. Silver and Deming bits have reduced shanks. I have found full sized bits to be more accurate.


Scott


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## Chipper5783 (Oct 8, 2015)

Jobber are regular length, ordinary drill bits.  S&D are generally considered larger than 1/2", but with 1/2" straight shank (it may be they are any reduced shank drill bit).

I suggest you get a 1/16 - 1/2",  "middle of the road" HSS set of bits (don't get the real cheap ones, but expensive bits are easy to damage - go for the middle).  Your favorite tool supplier will have some that will be fine.  Only get cobalt or carbide for specific tasks.  Drilling is pretty rough / crude (extremely useful) activity.  Drill bits get consumed, for all sorts of reasons.  You'll get used to sharpening, grinding to a different point (i.e. for flat bottom holes), burning the corners off, cutting the shank short, cutting the entire bit short - after a few years you'll end up with hundreds of drill bits (I have a lot that other people have thrown away - cut the chipped & burnt end off, repoint, clean up the shank - away you go).


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## Doubleeboy (Oct 8, 2015)

You could google Jobber bits and S&D bits if you have internet access.  For brands buy something made in USA or Japan if you want quality.  Want to save money buy China and take your chances.   Chicago-Latrobe, Cleveland, Precision Twist all make the good stuff, none of them cheap.

michael  with the lame avatar


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## JimDawson (Oct 8, 2015)

I buy the Harbor Freight drill bit sets, on sale!  I have bought several sets of both the black and TIN coated.  I also have a S&D set from HF.  The black bits are normally sharpened correctly, but many times the TIN coated ones don't have enough relief and need to be sharpened before use.  Not a big deal, only takes a minute.  I don't have any, but I have heard the the HF cobalt bits are pretty good.

Drill bits are expendable so for normal everyday use, cheap is better IMHO.  If I need good drill bits or specials for a job, I buy them in the sizes I need and normally buy a package of 10 or whatever they come in.


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## coolidge (Oct 8, 2015)

For a lathe I'd want the bits short and stout. The average off the shelf standard length cobalt bits in larger diameters don't work well in my lathe even if you drill in steps e.g. centering bit, 1/4 the 3/8, then 1/2 inch. The 1/2 inch bit is too long, add the chuck, add the tailstock slop and the hold will be off center. I gave up and just use a boring bar now for holes beyond a certain size.


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## Swerdk (Oct 8, 2015)

Thanks guys


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## Ulma Doctor (Oct 8, 2015)

I have drills for specific purposes and materials- everything from carbide to HSS to Cobalt to  Carbon Steel, Cheap to Expensive
for your everyday drilling, i'd suggest HSS drill bits for most applications.
2 reasons, 
they are relatively inexpensive,
and they are easily resharpened by hand with a bench grinder (i have sharpened them with a 4.5" angle grinder too)

if you are going to be drilling harder materials, i'd suggest a set of cobalt bits from a reputable manufacturer (but the HF cobalt bits are not bad for the price)
i got some great ones from a Snap On Tool truck 25 years ago, but they were an arm and a leg even back then,
i still have the set, but i have had to replace a couple dozen of them at one time or another. the small bits get abused/break more than the larger ones.

I have never had any luck with TiN coated anything, maybe it's ignorance on my part- but i avoid TiN unless i'm going into wood or aluminum

McMaster has some good bits too, a little pricey but good quality
Chicago-Latrobe makes good bits
Black and Decker Industrial bits are surprisingly good too 
Triumph make excellent bits
KnKut makes some excellent bits as well


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## David S (Oct 8, 2015)

I do a lot of clock work and find the short screw machine bits to be helpful.  They are stiffer and if you are using a small lathe they give you more room for longer work pieces between the headstock and tail stock chuck.

David


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## Franko (Oct 8, 2015)

Once you sharpen or grind a TIN coated drill bit, it is no longer TIN at the business end.

I have a set of cobalt drill bits that I keep back and only use on special occasions.

In the wood shop, I have an inexpensive set of TIN coated bits.

I've also gotten drill sets that were on sale and looked pretty good, only to find that not even on of them was straight and would wobble at the business end.

I've noticed that S&D shanks have increased in diameter over the decades. The first drills had quarter inch chucks, so stepped shank drills were 1/4". Later the standard electric hand drill increased to 3/8". Nowadays, many compact drills have 1/2" chucks.

One thing I've noticed regarding the drill sets I own, is that the higher quality bits have tighter spiral flutes than the cheap sets.

I'm very fond of Dewalt "Pilot Point" drill bits. Not appropriate for every job, but they seem to be very good quality bits.


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## eeler1 (Oct 8, 2015)

Di too on screw machine drill bits.  Short, very stout, get a decent set and you'll be ready to drill


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## Swerdk (Oct 8, 2015)

One thing I've noticed regarding the drill sets I own, is that the higher quality bits have tighter spiral flutes than the cheap bits



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## Swerdk (Oct 8, 2015)

Why is tighter spiral flutes more desirable?


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## Franko (Oct 8, 2015)

I don't know why, Swerdk. I suppose it is possible they are more rigid. It is just an observation that cheap drill bits I've gotten tend to have fewer spirals turns.


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## Fabrickator (Oct 8, 2015)

I've tried a lot of brands including HF.  I have to say that the set I got from HF on sale only had about 12 bits of the set that were actually true (wobble or tip was mis-ground).  They will be used for the grandchild to kill some toys or something....

I like Hertel, Triumph and Precision - Screw Machine are the best for their rigidity, plus they provide more clearance on smaller machines.  I use Enco, Reno, NV when I get their sales with 20% off + free shipping. They also have excellent Cust. Serv. for returns.

*TIP:* No matter what brand you buy, I highly suggest that you "spin and touch" each and every one lightly in something (wood, aluminum) to check for true and a correctly ground tip. If it's good, you won't feel or see any movement w/equal chips. I only used one or two some years ago and didn't come across the bad ones until it was to late to return them (not to Enco, but another supplier).


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## RJSakowski (Oct 8, 2015)

On a bit with a finer pitch spiral, the cutting edge will have more rake.


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## Swerdk (Oct 8, 2015)

Thank you for suggestions 


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## chips&more (Oct 8, 2015)

I have migrated over to using stubby split point cobalt. And I have noticed major improvements in true position, life and an increase in feed rate. Of course if the hole needs to be deeper I change to a standard length drill bit. Sometimes now, I don’t even start with a center drill…Dave.


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## Charles Spencer (Oct 8, 2015)

Coincidentally, I recently received a set of 9/16" to 1" bits from Drill Hog on ebay.  I had various large bits that I had bought used that were name brands.  I found the ones I just received to be comparable in tolerance and "feel".  They say they are made in the USA.

Honestly I was a bit apprehensive due to the fact that the set only cost $60.00.  To be fair I have only really used the 7/8" one more than once on my lathe.  But I have found them accurate and sharp.  They come in a Huot metal case and are guaranteed for life.  

DISCLAIMER:  Absolutely no connection outside of buying them and really enjoying having such a cool looking set of large drill bits.


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## wrmiller (Oct 9, 2015)

Charles Spencer said:


> Coincidentally, I recently received a set of 9/16" to 1" bits from Drill Hog on ebay.  I had various large bits that I had bought used that were name brands.  I found the ones I just received to be comparable in tolerance and "feel".  They say they are made in the USA.
> 
> Honestly I was a bit apprehensive due to the fact that the set only cost $60.00.  To be fair I have only really used the 7/8" one more than once on my lathe.  But I have found them accurate and sharp.  They come in a Huot metal case and are guaranteed for life.
> 
> DISCLAIMER:  Absolutely no connection outside of buying them and really enjoying having such a cool looking set of large drill bits.



I have the same Drill Hog set, along with the 'full set' they offer. I too have found them to be quite accurate and very sharp. They claim Made in USA but I have no proof of this other than the observed quality. I have bought a few 'made in USA' things of late that were very disappointing (Aloris was one).

I even managed to snap a small drill bit while doing some deep drilling. When contacted, they promptly replaced the bit, offered some advise, and even shipped me a trial size of their recommended lube. Pretty good customer service.


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## gi_984 (Oct 12, 2015)

Hertel brand. Get a basic set of 1/16- 1/2 from Enco on sale plus wait for the 20% off codes with free shipping.  I wouldn't buy anything cheaper.  A set of these in jobber length and a good Jacobs chuck(US made) or Albrecht chuck will take care of most of your day to day drilling.  Anything over 1/2 inch I prefer using my Morse taper twist drill directly in the tailstock.  If you have a problem breaking drills( assuming you aren't drill too fast or deep with cutting oil) you have a alignment issue with your tailstock.


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## 65Cobra427SC (Oct 12, 2015)

Very good thread. Trying to make a list which includes drill bits. I signed up to receive emails from Enco several months ago but wasn't ready to buy at that time. Now I am but haven't heard from them in a couple weeks. Is this happening with everyone, or did they cut me off... or put me on their list for losers?


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## erichmatt (Oct 12, 2015)

I had a few sets of cheap drill bits that sort of worked but some of the drill bits weren't straight and some weren't ground correctly.  The bent drill bits do better in a hand drill than in a lathe or drill press.  With an hand drill you can start the point right in a center punch hole and the drill shakes a bit but you get a hole where you want it.  In a machine the drill point makes a circle above your piece making it hard to accurately start a hole.  Recently I decided to spend the extra money on a good set of drill bits.  I wasn't sure what brands were good so I bought a set from McMaster Carr.  They don't always tell you the brand name you are going to get but I have bought quite a few things from them and it is never crap.

McMaster Carr ended up sending Chicago Latrobe drill bits and their price on them was cheaper than what the same set would have been from Amazon.  I haven't had a chance to use my new drill bits very much but the ones I have used have been straight and well sharpened.


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## rcaffin (Oct 12, 2015)

Boxed sets of drill bits are the cheap end of the market.
Boxed sets of Chinese drill bits are the *really *cheap end of the market.
You get what you pay for.

I have found quite a few Chinese drill bits are mis-ground at the tip so they cut off centre, and the holes end up about 0.3 mm oversize. If the tip breaks through at the other side, the hole abruptly drops in diameter to the correct size. I use them for drilling timber these days.

Quite a few drills from the lesser ranked mfrs show a slight bend over all. It's not just the Chinese ones which do this. The bend is probably caused by asymmetries in the heat treatment. A bent or off-centre drill bit is utter death in a CNC.

I have resorted to buying Swedish Dormer drill bits in the required sizes (ie not in sets), and mostly stub length. I *trust *them. Yes, single Dormer drills cost more, but one Dormer drill bit is less expensive than two 'cheap' drill bits plus a wrecked job.

Cheers
Roger


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## SRDC (Oct 12, 2015)

I second Harbor Freight for run-of-the-mill. Used 'em in a small machine shop where we were doing a lot of medical research setups. Good and sharp. Dirt cheap. If you need to make sure you get them in the right place, use a center drill first - then the bit follows right in where you want it. Check the diameter with calipers or micrometers first if you're concerned about the size - most of the ones I've used came in right on par. If you're worried, you can always 'sneak up' on it - use a smaller size first, then go to the size you want - less chance of overdrilling.
That way, you can save your really good bits for only the most difficult/demanding jobs.


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## Dan_S (Oct 12, 2015)

for lathe work, I'd recommend you get a couple of sets of jobber length drill bits. $50 - $60 import sets are fine to start out with, and as the one you use most often dull, just replace them with high quality ones. 

1. number drill set (#1 - #60)
2. letter drill set (A - Z)
3. fractional set (1/16" - 1/2" by 1/64ths)
4. 60 degree center drills
5. 90 degree spotting drills

Brand wise I'm really fond of "Triumph Twist Drill", the Thunderbit line they make is amazing, but pricey.
http://triumphtwistdrill.com/thunderbit/


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## Dunc1 (Oct 13, 2015)

For starting a drilled hole you might want to consider "spotting bits" (see http://www.mcmaster.com/#standard-hole-starting-drill-bits/=zclfjm). I find these better at picking up a center punch mark than the more common center drills for lathe use.
I second an earlier vote for the DeWalt pilot drills. In Canada I find Dormer and Walter good brands.


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## wrat (Oct 13, 2015)

I have bits from various places including everything from Old Starretts to HF boxes.
While "get what you pay for" is a common mantra, I simply ask "what am i paying for?"  Or more precisely, "what would I pay more for?"
Which leads me to this:  yes, sometimes an incorrectly ground bit will walk.  But the grinder doesn't know if it's the cheapest bit or the most overpriced designer bit.  A HF bit tip can be ground just as precise as any bit, anywhere, only for very much less money.  
And when we talk about how 'precise' a bit is, I simply say, "it's a DRILL bit!  If i wanted it precise, the hole would get a different treatment."
If it's precision that matters, a drill bit is the wrong tool, especially all by itself.  On lathe or mill, I'd at least start with a center drill.  Then the tip wouldn't matter near as much.  Then use an undersize drill for material removal.  Maybe plunge an end mill for perpendicularity.  Finish with a reamer or a boring bar.  
That's when precision matters.
Otherwise, IMO, drills are just drills.  Nothing special.  So i don't spend like they are.

Wrat


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## The Liberal Arts Garage (Oct 13, 2015)

Checking drills for straight - Get a chunk of  plate glass 3/8" or more thick
Roll item in question, mirror doubles visible error. Mark, clamp in vise,
thhoughtful bump with lead hammer.......BLJHB


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## erichmatt (Oct 13, 2015)

wrat said:


> If it's precision that matters, a drill bit is the wrong tool, especially all by itself.  On lathe or mill, I'd at least start with a center drill.  Then the tip wouldn't matter near as much.  Then use an undersize drill for material removal.  Maybe plunge an end mill for perpendicularity.  Finish with a reamer or a boring bar.
> That's when precision matters.
> Otherwise, IMO, drills are just drills.  Nothing special.  So i don't spend like they are.
> 
> Wrat



For a project I was working on recently I needed to put a 3/8 hole in the middle of a 4 inch long 1/2 inch piece of round.  We were going to ream it later to get a more accurate size but the hole needs to be pretty close to down the center of the piece.  Sure drilling first then boring will get you a straighter hole than drilling but how are you going to bore a 3/8 hole that is 4 inches deep?  A reamer will give you a good size but it will want to follow the hole that was drilled.  We could drill it crooked put it on a mandrill and turn the outside, or leave it long and turn it between centers put in the ends of the hole but those options are harder than drilling a straight hole to begin with.  Drilling a straight deep hole with a bent drill bit probably isn't going to happen.  Sure the mandril option or the centers option would probably give us better results than drilling with a good drill bit the good drill bit is good enough and takes less time.


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## wrat (Oct 13, 2015)

erichmatt said:


> Sure drilling first then boring will get you a straighter hole than drilling but how are you going to bore a 3/8 hole that is 4 inches deep?



One way would be boring bar.  Boring bars don't always have to be single point, either.
Another way would be to plunge a 4 flute endmill.  Need a clearance hole, usually, for 4 flute.  Lots of long endmills out there.
Core drills are about as precise as reamers.  Like a reamer, they'll tend to follow the hole, though.  But they move material nicely.
Then there's always a gundrill.  They make very deep and very accurate holes.
What are the feature requirements?  Cylinder, diameter, etc.?
I guess it depends on several questions like material, how accurate, and how many $$.
Certainly not impossible.

Wrat


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## erichmatt (Oct 13, 2015)

wrat said:


> One way would be boring bar.  Boring bars don't always have to be single point, either.
> Another way would be to plunge a 4 flute endmill.  Need a clearance hole, usually, for 4 flute.  Lots of long endmills out there.
> Core drills are about as precise as reamers.  Like a reamer, they'll tend to follow the hole, though.  But they move material nicely.
> Then there's always a gundrill.  They make very deep and very accurate holes.
> ...



Most of those options require a hole to be drilled first and would benefit from have a relatively straight hole to start with.  

A 4 inch long boring bar that is thin enough to cut a 3/8 hole is going to chatter like crazy and require a very light cut and slow feed.  I looked on msc for long boring bars and the only one the comes close is one that has a minimum hole size of .360 in and a max depth of 3.125 inches.  So it's not quite long enough, guess how much it costs?  $339.  More than a whole set of decent number, letter, and fraction drill bits.  If you went for a boring bar that is supported at both ends with a tool cutter in the middle (like a line boring machine) you would have better luck but I can't think of a easy way to support both ends of a boring bar and hold the piece in a lathe. I am sure there are ways to do it but it would require a special jig or a whole different machine.  

A gun drill would be great but I don't know anyone who has one let alone any one who would let me use it.

Cheap drill bits have their place.  I am going to keep my cheap set for doing things that are likely to break a drill bit, like hand drilling in an awkward place or some other thing.  If I am going to do something that pushes the limits of how accurate drill bit can be I am for sure going to use the best drill bit I have.


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## wrat (Oct 14, 2015)

erichmatt said:


> Most of those options require a hole to be drilled first and would benefit from have a relatively straight hole to start with.


 Not necessarily.  Plunging an endmill only requires a clearance hole for the flute centers.  It doesn't care how straight the hole is.

Look if I can help out a little, cool.  You're obviously closer to it than me. But a few things i can tell you:

I have used boring bars of that length and smaller diameter.  But then, that was in the days of more tool grinders and fewer purchasing agents.  So no, it might not be readily available off the shelf because it probably never was.

I can also tell you it still comes back to material, feature, and tolerance, which we still don't know, and hey, it doesn't much matter if you tell me or not. But the entire process revolves around that.  The entire process.  If those are unknown, then the part isn't designed yet and no real requirement exists.  If those are known, then the process is a simple matter or at least simple decision.

Granted, those factors drive price.  So if you need 0.0001" over 4" in stellite, then it will cost more than 1.0" over 4" in white pine.  This may sound obvious, but it's still inescapably the driver and the more we know about material, feature, and tolerance, the more we know about process and therefore cost.

And cost is not just $$.  Because we know that Time = $$, we can then conclude that if you don't want to throw a lotta money at it, then you'll hafta throw a lot more time at it.  There's no free lunch.  Those are Rules of The Universe that cannot be changed. 

If the tolerance is "the best hole i can put in with a drill bit i can buy" then you really don't have a question.  Drill, baby, drill!  Done and done.  If there is no declared tolerance, then it's time to start understanding holes and other machined features.  If the question is about "which drill bit?" then it's a discussion of superstition like asking "which is the best pickup?" or "what's the best beer?"  Starts good arguments (uh... discussions ;-) but yields little useful information other than the identities of argument participants.

Regardless, none of this is new or unique and has been well-studied and published since before either of us were born.


Wrat


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## John Hasler (Oct 14, 2015)

erichmatt said:


> For a project I was working on recently I needed to put a 3/8 hole in the middle of a 4 inch long 1/2 inch piece of round.  We were going to ream it later to get a more accurate size but the hole needs to be pretty close to down the center of the piece.  Sure drilling first then boring will get you a straighter hole than drilling but how are you going to bore a 3/8 hole that is 4 inches deep?  A reamer will give you a good size but it will want to follow the hole that was drilled.  We could drill it crooked put it on a mandrill and turn the outside, or leave it long and turn it between centers put in the ends of the hole but those options are harder than drilling a straight hole to begin with.  Drilling a straight deep hole with a bent drill bit probably isn't going to happen.  Sure the mandril option or the centers option would probably give us better results than drilling with a good drill bit the good drill bit is good enough and takes less time.


Drill from both ends with a 23/64" stub bit.  Drill through with a 23/64" jobber bit.  Ream to size.


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## erichmatt (Oct 14, 2015)

John Hasler said:


> Drill from both ends with a 23/64" stub bit.  Drill through with a 23/64" jobber bit.  Ream to size.


Good idea, I would still rather use good drills to do that process rather than cheap ones.


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## Dan_S (Oct 14, 2015)

erichmatt said:


> A 4 inch long boring bar that is thin enough to cut a 3/8 hole is going to chatter like crazy and require a very light cut and slow feed.  I looked on msc for long boring bars and the only one the comes close is one that has a minimum hole size of .360 in and a max depth of 3.125 inches.  So it's not quite long enough, guess how much it costs?  $339.  More than a whole set of decent number, letter, and fraction drill bits.
> .



as someone else mentioned, The material and the tolerance are important. The tool geometry is also pretty important.

if the tolerances are tight, it must be bored, or bored and then reamed.

The cheapest way, would most likely be to buy a  solid carbide bar like this one, and then braze/solder a cutting bit onto the end. The bar itself could also be ground into a solid carbide boring bar.
http://www.mscdirect.com/product/details/48611305

This thread shows a custom brazed bit.
http://www.hobby-machinist.com/threads/homemade-boring-bar.18364/




erichmatt said:


> If you went for a boring bar that is supported at both ends with a tool cutter in the middle (like a line boring machine) you would have better luck but I can't think of a easy way to support both ends of a boring bar and hold the piece in a lathe. I am sure there are ways to do it but it would require a special jig or a whole different machine.



You just clamp v blocks to the carriage (shimmed as needed), and then turn the bar between centers.


The third option, would be the Kelly Johnson (SR-71 designer) method, don't let the engineers design difficult to produce parts.


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## planeflyer21 (Oct 15, 2015)

John Hasler said:


> Drill from both ends with a 23/64" stub bit.  Drill through with a 23/64" jobber bit.  Ream to size.



Will it be straight?


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## neshkoro (Oct 15, 2015)

Right from Wikipedia:

The *spiral* (or rate of twist) in the drill bit controls the rate of chip removal. A fast spiral (high twist rate or "compact flute") drill bit is used in high feed rate applications under low spindle speeds, where removal of a large volume of swarf is required. Low spiral (low twist rate or "elongated flute") drill bits are used in cutting applications where high cutting speeds are traditionally used, and where the material has a tendency to gall on the bit or otherwise clog the hole, such as aluminum or copper.
Bill


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## John Hasler (Oct 15, 2015)

planeflyer21 said:


> Will it be straight?


Fairly.   The stub drills will make pretty straight holes (if they are good ones).  The one on the entry side will act as a drill guide for the jobber-length one so that it will start straight into the middle section, which will be much shorter than the total hole length.  The reamer will take out any irregularity under a 64th.  I suppose you could drill at 11/32", core drill at 23/64", and then ream.  That's a lot of operations, though, not to mention the cost of the core drill which you will probably never use again.


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## erichmatt (Oct 15, 2015)

John Hasler said:


> I suppose you could drill at 11/32", core drill at 23/64", and then ream.  That's a lot of operations, though, not to mention the cost of the core drill which you will probably never use again.



This was very close to the process we ended up using.  We were making sleeves to repair very worn out valve guides that were part of the block.  The first few we did stub drill and then the rest of the way with a jobber.  It worked ok but could be better.  Today we switched to stub drilling from both sides then finishing the middle with a longer bit.  They came out quite a bit better, sighting through them you could barely see were the holes met.  We then installed them and core drilled them and then reamed them to the final size.  When we drop a valve in it bounces nicely so the new guide is lined up with the old seat.


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## samthedog (Oct 19, 2015)

rcaffin said:


> I have resorted to buying Swedish Dormer drill bits in the required sizes (ie not in sets), and mostly stub length. I *trust *them. Yes, single Dormer drills cost more, but one Dormer drill bit is less expensive than two 'cheap' drill bits plus a wrecked job.
> 
> Cheers
> Roger



I recently bought a set of Brazillian made Dormer bits and was so impressed I went back and bought 3 more. I use Titex, Dormer and Walter drills and these Brazilian bits were as good as Swedish dormer or SKF bits. I have found the grind and the steel to be top quality and the price is right too.

Paul.


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