Ahm thinkin all's you really need are drills for screw clearance and tapping -- mebbe roll taps as well. What else? Pins, roll pins, I guess, but I don't use those much.
Metric: Most common: 3, 4, 5, 6, 8 mm?
I have Huot bulk drill case, in a small shop. The oddball sizes I figger a cupla drills would be enough, but for things like #7, 21, 1/4", etc, I should have at least 10 on hand.
Probably drill point angle would be an issue as well. Get 118 and 135 deg? If I just went with one angle, what would be better?
In general, is cobalt worth the extra $? Coated? I proly break shit before I wear it out..... :(
Any shop should have a least one complete set, as a job shop I have no idea what the next job in the door will be and what size drills I will need. I do stock up on the common sizes. I have several of the big Huot cabinets.
Re:metric Get the most common clearance and tap sizes for those. And you'd be surprised at how much you use those off sizes in the regular 115 piece sets. I'm always needing a drill just a bit bigger for drilling out busted screws and the like. If I could get a metric set for a decent price by tenths(and refills!), I could probably chuck all the fractional/letter/number stuff. It's always been a mystery, with 90+% of the world on the metric system, how we end up being screwed on metric tooling costs.
As far as cobalt, I've found these useful for the harder steels, like on guns. For aluminum, probably no advantage. They're brittle, so if you do a lot of free-hand drilling, prepare to buy spares. There is no one drill type and material that's going to do it all.
Isn't Shars just another importer? My Shars (has Shars etched on them) vises came in Chinese crates even though they shipped to me from your neck of the woods.
P.S. I am very happy with my large (6" opening) Shar's vises by the way. I did have to do some minor improvements on the cross bar assembly, but at the price I can't complain. The machined bodies of the vises are superior in accuracy to anything I need at this time. I'm considering buying 3 of their small 1" step jaw vises for small stuff, for the machine I intend to dedicate to drag engraving, and for use as a lower profile two piece vise.
To the OP. I have a couple of the 115 sets. I like being able to pick up the decimal drill bit chart and then pick out a bit within a few thousandths of of what I want every time. I've have/had a Tin, Cobalt, and HSS sets. The cobalt coated do seem to last longer initially, but after they get a bit worn they are all pretty much the same. I also find that I mostly use the same bits over and over again, so for certain things I'll probably bulk purchase bits in specific sizes in the future. In my contracting business I already by 3/8 bits by the half dozen. D & F also get used a lot for setting alignment pins in molds. Also, 21 & 7 for clamping screws.
The big thing is organization. A 115 pc set is wonderful until you push it off the work bench once. The bigger sizes are no big deal, but all those smaller number sizes are impossible to sort again. I get a new cabinet (new to me) and decided to put my newest 115 piece set in a drawer and never take it out so that couldn't happen. Didn't really realize that it didn't have proper drawer slides so of course the first time I left the drawer out while I turned to check one of my size tables it fell on my foot. Not only did my toe hurt for three days, but now I have a drawer full of loose bits I scooped off the floor. LOL.
Anyway, my thought on buying specific sizes you use a lot is develop a good system for keep new unused bits, good used bits, and worn bits straight by usage and size.
--If you can buy the empty boxes and fill 'em with quality drills as you need 'em. I've got two: one for jobbers and one for stubbies; both filled. Ya never know when you'll need an oddball: customer called the other day and is sending a bit I *still* don't have to do a special job; funny how that works out... For common sizes it's a good idea to get spares and keep 'em safe somewhere; I tend to buy these 5 at a time..
I like cobalt bits for drilling stuff like steel pipe. However, with small diameter bits, it seems more likely you'll just break them before they wear out.
I have a budget Enco set of HSS - nothing fancy. When I wear out or break one, then it's time to consider getting a better drill bit (or bits) in that size. As such, the sizes I haven't used are not costing me much, but I have something in all sizes. If not budget constrained, or less hobby and more production, different economics may apply.
TiN is coated. Cobalt is cobalt through and through - if sharpened properly, good as new. If you just run them dull and toss, different economics again.
Easy as reading a micrometer. Something you can set the apprentice or kid on if you have one or the other and a slow period. Or do yourself, unless you bring in so much money that it's worthwhile to just buy a new set rather than take the time. Most places there's somebody who can be useful at least part of their time doing background tasks like sorting drill bits.
I sorted the contents of my many drill indexes into these:
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They seem expensive but pay for themselves the first few times that you can continue a project because the proper bit is available rather than hidden away in a forgotten drawer.
It depends on your usual material and what you are using to drive the drill, i.e. loosey-goosey drill press, Bridgeport, lathe, etc. In general the sharper points work better with softer material and the blunter points [135 degree] work better for hard material. The 118 degree is a general point. A 135 degree w/ or w/o split point will tend to walk less than a 118 degree point. Unless you have a need to drill the deeper holes, the jobber length drills flex more. Without anymore information on what you are doing I suggest
135 degree screw machine length drills. One source is
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Cobalt, while it increases the heat/wear resistance also makes a drill more brittle and prone to breakage/chipping. Unless you are in high volume production with rigid equipment, good quality HSS drills will most likely be more satisfactory and economical. TiN coating can be helpful in reducing chip welding.
One dodge that I have found helpful is to notice which taps/drills I use the most frequently, and buy both taper and bottoming taps, and possibly a gun tap, with 135 degree split point drills for a tap drill, and both tight and lose body clearence. I like to keep the taps and drills in a plastic reloader box as this keeps everthing together and protects the tools.
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-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).
My experience and usage is the same as yours. I've also found them useful for measuring holes and clearances where I couldn't get in with anything else to do the measuring.
Buy a couple cheap assed sets and fill the hout up with them...
After that ( since IIRC you basically have a dedicated product line) I would suggest buy any sizes that you routinely use in production on an as-needed basis by purchasing at full package quantity and in the particular style that the job dictates.
For instance, while my own kit has copius amounts of spare stub length drills in certain sizes, which are often used for pre-reaming dowel pin holes, ( eliminates the need for center-drilling ) as well as for clearance and tap drill sizes for the 1/4-20 and 10-32...( and usually they brights because I mostly machine aluminum ) it also has quite a few empty spaces--spaces which I see no need to suddenly rush out and buy replacements because they are basically oddballs sizes antways.
I finally broke down and bought the Enco $100 118 degree set a couple of years ago & am glad I did. They have been ok. Very useful to have the size selection on hand.
BQ340 fired this volley in news:4d892619$0$23135 $ snipped-for-privacy@newsreader.readnews.com:
They are not accurately sized or ground on center.
All of the cheaper sets tend to drill oversize because of off-center tips, or gall because the metal was not properly tempered, or do so because the rake angles are mis-ground.
A digital caliper is close enough to determine what goes where. Measure across the flutes at the tip, because the shank is often a little smaller than the tip. And at least the Huot indexes mark the decimal diameter by each hole -- even decimal inches on the metric sets. (Yes, I keep a pair of metric sets -- 1.0-6.0 mm and 6.1 to 12.0 mm to both give the right size for metric hardware, and to fill in gaps in sizes between the letter, number and fractional sets.
Ouch!
But it is worth your time (you are a hobbist, are you not) to sort them properly back into the index. If a commercial machinist, your time is money, and you may be better off getting a new set to save you time finding the right bits from that drawer. :-)
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