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Machining For Dummies......Cheap Dummies

Posted: 29 May 2008 12:36 pm
by Jon Light
I'm a decent tinkerer with some ok woodworking tools and chops but I want to get into some light-weight machining----stuff like fabricating and tapping flags on knee levers, putting Emmons style volume pedal tabs on my pedal rack, etc.....not ultra high tolerance work and all for me, not for any commercial applications. I've got a cheap tap & die set. I've got a full size floor standing drill press, adjustable from 250--3100 RPM.
What I need is cheap drill bits. They don't need to last a life time. Or even a month, I suppose----some ebay sets are cheap enough that as long as they work 3 or 4 times I've gotten my money's worth.

So the question----

---will a 60 piece ebay titanium high speed set for under $20 drill me a few holes or is it a total joke? Would I do better to get a couple of step bits?

Please---I understand that high skilled craftsmen will bristle at the notion of cheap tools but I simply can't afford to gear up. On the other hand I don't want to throw even small amounts of $$ away on stuff that won't even give me a couple of workable projects.

Hey, while I've got you here----what drill speed would you recommend?

Sure hope I can get some helpful info. Thanks.

Posted: 29 May 2008 1:36 pm
by Donny Hinson
Some cheap sets might work fine, others might not. What you miss out on with bargain prices is quality control - there is none. I've seen some decent cheap drills, and then I've seen others that had points that looked like a child ground them on a bench grinder.

All is not lost, though. For the average drilling you'll have to do (which will be in aluminum), you don't need the best bits. Invest in a drill-press vise (holding parts with your hands while drilling isn't recommended), and a good hacksaw, and you're in business.

Remember to use some oil or grease when you're drilling and tapping, and keep the drilling speeds low (between 600 and 1200 RPM).

Posted: 29 May 2008 1:50 pm
by Chris Lucker
It would be helpful for you to find one of the old Using a Southbend Lathe booklets or some used book teaching you the basics of machining.

You will learn proper drillbit size for tapping holes and proper thread pitches in aluminum vs other harder metals -- when to use 10-24 vs 10-32, for example.

You will also learn how to think about rpms in a drill press. Think surface speed, not rpms. cutting fluids for aluminum are different than those used for brass or ferrous metals.

I don't think there is economy in buying a 60 bit set of cheaply made bits. You are going to snap off your 0.0625 bit in something important you are working on and really ruin your day. And you are going to be buying better bits to replace the four out of the 60 that you actually use

Learn something about machining, learn about the different bits available (read descriptions at McMaster Carr, even)and determine the few bits that you will actually need and buy some quality tools. You will appreciate missing out on some headaches.

Posted: 29 May 2008 2:08 pm
by Jon Light
Donny--thanks. That is helpful.

Chris--sincerely, thank you for the thoughtful response. Most everything that I know how to do I learned from trial & error or from working alongside someone who knew what he was doing, or from picking up general knowledge from who knows where. But machining is something that pretty much escaped me and I really just haven't been able to come up with a clue as to how to gain knowledge (and it never occurred to me that there was any book learning to be had). As a product of expectations that I would go to college and do academic stuff, I never had access to high school trade courses. And when I dropped out of high school just to burn some people's butts it left me in no man's land. But I've spend almost 40 years working with my hands and I'd like to learn some of this stuff. Because I'm pig headed it is likely that what you say about decent gear is something I will have to learn the hard way. But please don't take that as any sort of rejection of the wisdom of your advice. I appreciate it.

Posted: 29 May 2008 2:45 pm
by Bill Moore
Jon, small drills will break, it's handy to have several of the size you use most. If you get a set, you will get one of each, some of them you might never use. Industrial supply stores, like Grainger, sell all kinds of drills, maybe you can locate one near you. Enco is also a good source. Center drills are handy, makes it easier to locate a hole just where you want it, then finish with a regular drill.

Posted: 29 May 2008 2:57 pm
by Doug Earnest
Like Bill said, you really don't need an entire set for what you want to do. Buy some GOOD ones in the sizes you will need up to 1/4". It's really cheaper to buy the better ones. Enco is a pretty good place as is Fastenal.

Posted: 29 May 2008 3:21 pm
by Michael Maddex
All these people have given some good advice. Here's my two cents worth:

You can find copies of the old lathe books and lots more at Lindsay Technical Books.
Grizzly is a good online source for woodworking and machine tools. The owner is a part-time luthier.

I have bought cheap tool sets in the past, knowing when I did that the most commonly used sizes would wear out or break and I would be replacing them individually as needed. I wouldn't go that route with drill bits, though. Buy good ones as you need them. For small drill bits, I usually go to my local real hardware store, not one of the national chains, where prices are higher but quality still counts, and purchase two to six bits of the same size at a time. Even if I don't break one on the current project, I know that it's only a matter of time.

HTH.

Posted: 29 May 2008 4:18 pm
by Jon Light
Super. Nothing but high quality responses here & on my PM.
I will look into book learning. Didn't know it existed. I will consider cutting down on the variety of bits---you see, I got one of those 80 piece tap & die sets so I kinda wanted every drill bit size known to man so I could use all the taps.:roll:
Can anyone suggest the few sizes that I'd most want in my kit for the sort of jobs I mentioned in the original post? The kinds of bits I'd use on a steel---knee levers, half stops at the changer, pedal rack stuff.....
And how about those step-bits with many diameters on one conical shaft---jack of all bits, master of none? Or a useful option?

Drill Bits

Posted: 29 May 2008 4:25 pm
by Martin Weenick
Jon, a good place to look for drill bits and taps are flea markets and pawn shops that usually have boxes of bits laying around. Look for ones with "USA" on them.

Posted: 29 May 2008 4:54 pm
by Donny Hinson
Jon, go on ebay and look for either a "Machinist's Handbook", or the "Machinery's Handbook". These are books chock full of good info (like 1500 pages worth), more than you'll ever need. With luck, you can pick one up for under $5, and even the older ones (from the '40s and '50's) are fine. Up until CNC machine's and computers came along, these were the "bible" for any good machinist.

Posted: 29 May 2008 5:13 pm
by Bill Hatcher
Hang out here. LOT'S of good info.

http://www.practicalmachinist.com/vb/index.php

Posted: 29 May 2008 5:17 pm
by Papa Joe Pollick
You're also gonna need a small bench grinder to RE-SHARPEN the bits.The ones that you buy will be sharpened for STEEL and will grab softer metal and either break or twist the work out of your hands.When drilling soft metal you want to chip,not cut.MHO..PJ...

he

Posted: 29 May 2008 6:45 pm
by Russ Little
Jon,
Just a reminder that no one mentioned
the larger the bit the slower the speed.
and don't rush it give it time to cut.

Posted: 29 May 2008 7:13 pm
by Andy Jones
Jon,I bought some cheap drill bits at a tool sale that frequently travels around the country.I call them "styrofoam bits" because that's all they'll drill a hole through.Spend a few more bucks and get some bits that you can use.

Andy

Posted: 29 May 2008 8:01 pm
by Dave Wright
I bought a cheap set of Drill Master bites from harbor freight a few yrs ago. And, they have lasted a few yrs and probly a few more. I use them for everything. steel wood aluminum and a finger or two :whoa: .. For the price You cant beat it..

Posted: 29 May 2008 8:16 pm
by Jim Sliff
I use a $50 drill press from Big Lots and cheap drill bits from there or Home Depot - I can't remember because the main ones I use I bought so many years ago I don't recall. I think I've broken one, and that was on a chair when I hit a nail drilling wood. Maybe I've been lucky..but then so has my neighbor who also has, like I do a mix of cheap stuff and good stuff. I've never sharpened a bit in my life and I drill aluminum, wood of all kinds, brass...I'm sure there's something to be said for quality of some tools, but there's hype as well; we used to buy pin vises (small hand drills) at work for $25 each; no I get ones that work perfectly for $2.00. Our guys were burning up $200 grinders, so almost as a gag I bought 4 $22 Chinese ones 2 years ago that they can't seem to kill.

But as I said, maybe I'm just on a long lucky streak...

Posted: 30 May 2008 4:16 am
by Ron McLaren
The main problem with drilling aluminium is the fact that it will fuse to the cutting edge of the drill, to prevent this use some kerosene as a cutting lubricant, WD40 will also help.

It's one of the few uses Ive found for WD40! :)

Ron Mc

drills

Posted: 30 May 2008 6:32 am
by Marvin Born
There are two lengths of drill bits available. Jobber length are the normal size that we buy at "Home Depot." There is also a "machinist" length that is somewhat shorter, maybe 60% of normal. When used in a drill press they are much stronger and more accurate due to their shorter length. There is less tendency for them to walk around when starting a hole from a center point mark. You will probably have to go to a tool store to find them. Eventually, you will learn that you only need a few sizes and not a whole set.


Also check E-Bay and look for a little combo lathe/mill called a Unimat SL. These are very hand for small stuff on guitars. They are no longer made, so they can be hard to find.


Marvin

Posted: 30 May 2008 9:50 am
by Chris Lucker
Donny made a great suggestion -- the little green (mine is green) machinists handbook. I think it cost $3 in a used book store. You will see the proper drill sizes needed for tapping particular holes.

You probably need a quality set of drills in 1/16, 3/32, 1/8 (several)1/4, 5/16, 3/8, 1/2, 3/4 and a full inch I don't know if your chuck can handle above 0.750?)
After that you will fill in with an array of numbered drill bits for proper tapping of holes.

Also, you will really want to follow the suggestion of and get some

Posted: 30 May 2008 9:55 am
by Chris Lucker
Donny made a great suggestion -- the little green (mine is green) machinists handbook. I think it cost $3 in a used book store. You will see the proper drill sizes needed for tapping particular holes.

You probably need a quality set of drills in 1/16, 3/32, 1/8 (several)1/4, 5/16, 3/8, 1/2, 3/4 and a full inch I don't know if your chuck can handle above 0.750?)
After that you will fill in with an array of numbered drill bits for proper tapping of holes.

Also, you will really want to follow the suggestion Bill Moore and get some center drills -- they are very stiff and stable and do not wander -- they start a hole where you want it to be even on round rod.
Learn about drills first -- the shape and numbers of flutes are designed for cutting different materials, depths, speeds, etc. It is not really interesting stuff to learn as much as it makes life a lot easier, especially if working with a sticky gauling metal such as 6061-T6 aluminum which you probably will.

Posted: 31 May 2008 2:19 am
by Tony Smart
If you're buying drills, always go for the High Speed Steel (HSS) ones.

Carbon, or high carbon steel drills are false economy. They're alright for drilling pastry, but no-one in the trade uses them.

Posted: 31 May 2008 2:26 am
by Ken Byng
Tony Smart wrote:If you're buying drills, always go for the High Speed Steel (HSS) ones.

Carbon, or high carbon steel drills are false economy. They're alright for drilling pastry, but no-one in the trade uses them.
Tony - you might try using a fork when aerating pastry. Much easier than using a Black & Decker. :D

Posted: 31 May 2008 4:21 am
by Tony Smart
Ken,
Being a true Cordon Bleu, you must know that the only way to make authentic sausage rolls is to drill the hole for the sausage.

Do you recommend a 7/8" sausage or the (John Hughey) 15/16"?

Posted: 31 May 2008 5:05 am
by Ray Minich
I've always had a special place in my heart for the ones that say "Cleveland Twist Drill" on 'em...

Posted: 31 May 2008 5:09 am
by Jon Light
I sure wish you guys would not spread such incorrect information. Everybody knows that pastries are sand-cast or injection molded.
I did try to turn a donut on a lathe once but I could never find the center of the hole to mount it. I brought it to powder-coating shop to finish it but it wasn't as delicious as the name had led me to believe.