Finally a gloat for me



--
Thank you Don. At the moment, I can cope with the 2 types of
countersinks I have seen - yes, I know the woodworking ones are
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Doing layout work on square tubing is easy. You need a decent machinists square and a scribe.
When you mark the location of a hole on one side, set the square with the straightedge perpendicular to the length of the tubing on the first mark, and scribe around to the opposite side. When the line is scribed all the way around, the ends will meet if some attention is expended during the exercise.
With a little care, the holes on opposite sides of the tubing should be within/less than .010" difference. That will probably be as close as just drilling thru the tubing can attain.
It's a good practice to pilot drill holes with a 1/8" split-point drill for holes of 1/2" or larger. When the layout work and the pilot holes are placed accurately, the larger holes are generally (nearly) perfectly located, and cut substantially faster.
Everyone working with metal should have a variety of split-point drills in sizes up to about 1/4". The split-points start cutting immediately upon contact, unlike a conventionally ground drill point.
The web in the center of a conventionally ground twist drill is similar to a cold chisel with a slightly crowned edge. This edge isn't a cutting edge, it just displaces metal as force is applied, before/until the cutting edges contact the metal. The trouble is, the drill continues to require a significant feed force to continue drilling. For larger sized drills, the force required to get the cutting edges into contact with the metal just generates unnecessary heat, then continues to generate more heat until the hole is finished.
It should be obvious that a good cutting lubricant is going to be a major benefit. Application of a small amount, as little as a quick swipe, with a small paint brush (or disposable acid brush) before starting each hole is generally adequate. Laboratory wash bottles with a dip tube and an extended spout are a handy method of applying cutting lubricant for drilling, milling, sawing and turning on a lathe.
Again, cutting lubricant doesn't need to be flooded on, just enough to keep the cutting edges wet, so it's not going to be an expensive practice.. instead, it will reduce cutting time and extend the time of the sharp edges on cutting tools.
For large holes, a good guide for the size of the pilot drill is the width of the chisel edge of the web. Then the pilot hole will allow the large drill to start without a lot of force. The objective is to generate chips, not watch a drill spin around.
As I've mentioned before, creating split-point drills isn't a difficult task. By examining a factory-made example of a split-point drill (a larger one is easier to see), one may notice that there are flats ground at a low angle to the point, on the trailing/back sides of the flutes.
The back side grinds are made first, then the point is ground in the usual manner, and the split points will magically appear.
--
WB
.........


"Jon Danniken" < snipped-for-privacy@yahSPAMhoo.com> wrote in message
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Wild_Bill wrote:

Thanks Bill, I appreciate it. This project will be a good exercise for me to work out layout and indicating for me. I have seen how indicating is done with an X-Y table, but I have always had a tricky time lining things up when the table is not adjustable with such precision, as is the case with my drill press. What I end up doing is setting up the clamping to be not quite as tight as I need it, then gently tapping until everything is lined up. I don't know if there is a better way to do that outside of a proper X-Y table.

Ah, thanks, that is an excellent suggesiton. Pre-drilling both sides with a small hole would make it a breeze to punch through both sides with the big drill.
I will definitely keep my eye out for a split-point collection.

I picked up a little bottle of RapidTap yesterday from the local tool shop. I guess it's high time I started to treat my operations as actual metalworking.
Thanks again Bill,
Jon
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A commomly practiced method for lining up a small pilot drill with the center punch mark, before clamping the workpiece, is to:
-have the clamp set slightly loose on the workpiece (or vise), drillpress motor off -bring the quill down so the drill point sets into the punch mark -move workpiece to the location where the drill point enters the punch divot without deflecting -set the clamp -bring the drill point to the punch mark once more, to see that there is no deflection -then, with power on, drill the hole
These steps insure that the quill will push the drill straight into the punch mark. An X-Y table won't necessarily align the punch mark any faster or more accurately.
A basic set of layout tools and a little experience will prepare the workpiece for accurately placed holes. The final accuracy is up to the operator.
Getting accurately-placed drilled holes in metal is far easier than working with wood, IME (thin sheetmetal excluded).
--
WB
.........


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Wild_Bill wrote:

Hi Bill, and thank you for bringing up an issue which has been plaguing my attempts to layout square work pieces for quite some time.
I have a small combination square, and it constructed along the lines of the type "A" in the following figure (looking down the long axis of the base):
http://img717.imageshack.us/img717/5493/squaree.jpg
Does a proper machinist's square use a similar method of attaching the blade along the centerline of the base? For instance, this one I am looking at from MSC (SPI 13-626-7):
http://tinyurl.com/2cyrbvc
The issue I am getting at, is that I have trouble scribing a continuous line around the circumference of a piece of square tubing, because a scribe line along the edge of the blade will not line up with a scribe line along the edge of the base (it will, of course, be parallel to it).
It would seem to me that square "B" from the first figure would facilitate scribing a continuous line around a square piece of stock.
Are machinist's squares, like the SPI one I linked to, constructed along the lines of drawing "B", or if not, what is the technique to use a square of type "A" to do so?
Thanks for your help on this issue; this has been a thorn in my side for some time now.
Jon
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If I understand the method you're questioning, it would be described as, putting the square tubing in the inside corner of a square. That's not the proper position of the square, for doing the layout work we've been discussing.
The method I had described is done by placing the square straightedge (or rule) flat on the tubing side, and perpendicular to the length of the tubing. The straightedge is laying flat on the side of the tubing. The thicker part of the square is then touched/held on the adjacent side of the tubing, with with the length of the thicker part alongside the tubing. The straightedge will then represent a line across the tubing that is square to the length.
Most formed square tubing has a significant radius at each corner, but the face of the thicker part of the square can be extended if needed. The contact face of the thicker part of the square could be extended (sideways) with a parallel or similar flat piece of stock, by attaching it with thin double-sided tape (not the foam type). The wider surface would bridge the radiused area, and allow surface contact with the adjacent side.
Generally, I just tilt the thicker part of the square slightly, to make flat contact with the adjacent side of the tubing. This will cause the straightedge to stand up slightly on the tubing, but the inner/inside edge leaves close contact for scribing a square line.
There are squares that are both styles you illustrated, but the more common type has the straightedge located in the center of the thicker section (A).
When scribing the lines on square tubing with radiused corners, one needs to "sight" the lines of adjacent sides, since the line scribed on one flat side of the square tubing won't continue over to the next side. Solid square stock (like some lumber) has sharp corners, so a scribed line is easier to extend around the four sides.
If a precisely squared section of angle iron were used for the square tubing layout job, the two adjacent sides of the angle would show a continuation from a scribed line on one side of the tubing to the next side.
--
WB
.........


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Wild_Bill wrote:

Hi Bill, and thanks again for your help. Now that I understand this method, I will certainly acquire a proper square. I do agree that my current project may likely be more suited towards using a well-squared section of angle iron (due to the large corner radius), but the layout accuracy of my other projects will benefit from the addition of a square to my arsenal.
On the topic of squares, I looked at the one I am considering getting:
http://tinyurl.com/2cyrbvc
but it looks to be of a type represented by model "B" in the following figure:
http://img228.imageshack.us/img228/9239/square02.jpg
If this is the case (I cannot get a good enough look at the square to tell for sure, but many other squares seem to be of that type), I would not be able to use it using the method you outlined.
Do you know of a similarly priced (<$20) square or series of squares which would be constructed similar to model "A"?
Thanks again for your help with this,
Jon
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Likely made in India. Set on surface plate, check each one to the other three, you will see light if one or more isn't square. I have a set of 4 I bought years ago that is good enough for what I do at home.
Wes
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Different layout jobs require at least a couple of different types of squares. The combination types, with a sliding rule and 90/45 degree surfaces are very handy to have. Scribing a measured line parallel to an edge is one good use. An accessory for a good combination square is the V that is useful for marking the center of round objects. The trouble with many import/generic low-priced combination squares is that the components are cheaply made, so they aren't likely to last long.
A good quality combination square will practically last indefinitely, if it gets the proper care.
The fixed-type squares you've been referencing are useful too, regardless of whether the straightedge extends outward from the top of the thicker section (B). The fixed type squares will stay accurate, unlike the cheap combination-type squares with low grade components. The accuracy of the fixed types can be compared with precision 1-2-3 blocks (or larger) and a couple of precision parallels. Some careful filing can improve or restore the squareness.
Both types A or B would be suitable for your present task. Nearly all of the popular tool dealers have cheap import grade, and also better quality squares.
On rough, unfinished stock, there can be a lot of surface irregularities that may have a major affect on accuracy when checking square, or doing layout. Longer contact surfaces of squares can average out slight waves in the surface, as long as there aren't any "bimps" higher than the surface. Using a square that has a contact surface that's too small can lead to a lot of errors and frustration.
--
WB
.........


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Wild_Bill wrote:

THanks Bill, I appreciate your time.
Jon
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You're welcome, Jon. Anyone that shows a sincere interest in metalworking should, at least, be able to get some suggestions when questions are asked here.
--
WB
.........


"Jon Danniken" < snipped-for-privacy@yahSPAMhoo.com> wrote in message
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wrote:

Hey, that was a good score - AND you were really lucky NOT to get the teenage daughter as well, if you havent had one yourself, mm, ah, yes, ..............you are blessed!!! (hopefully, they grow up to be Human, rather than something just visiting from their home planet..)
Nice to have tools with a bit of grunt in them.
BTW - the car? - well, you know what a bullshit artist Gunner is, wouldn't believe that bit. OK with the teenage daughter bit - anyone want mine? - shes semi-house trained. (A lie well known to all parents)
Andrew VK3BFA.
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On Tue, 27 Apr 2010 06:15:55 -0700 (PDT), Andrew VK3BFA

http://picasaweb.google.com/gunnerasch
<G>
Gunner
"First Law of Leftist Debate The more you present a leftist with factual evidence that is counter to his preconceived world view and the more difficult it becomes for him to refute it without losing face the chance of him calling you a racist, bigot, homophobe approaches infinity.
This is despite the thread you are in having not mentioned race or sexual preference in any way that is relevant to the subject." Grey Ghost
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    [ ... ]

    The ones which you try to pretend are not .sigs by omitting the "-- " delimiter just above them. It used to drive me nuts as I would be reading along and hit a sudden change of topic with no warning. I finally realized that it was just another Gunner .sig and ignored them all.
    But really, it would make it easier for those who don't want to quote your .sig every time they followup to use the proper delimiter. It probably would do nothing for those who top post and quote the world, but for those of us who trim properly it could help.
    Enjoy,         DoN.
--
Email: < snipped-for-privacy@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
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wrote:

Ive used Agent for years, never changing anything internally and you are the first one to mention that its not working properly.
Shrug
Gunner
"First Law of Leftist Debate The more you present a leftist with factual evidence that is counter to his preconceived world view and the more difficult it becomes for him to refute it without losing face the chance of him calling you a racist, bigot, homophobe approaches infinity.
This is despite the thread you are in having not mentioned race or sexual preference in any way that is relevant to the subject." Grey Ghost
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    [ ... ]

    Actually, no I am not. I have seen it mentioned before (a few years ago), and I think that I even remember you responding that it was intentional, so people who have their newsreaders configured to hide .sigs would still have to see yours.
    Enjoy,         DoN.
--
Email: < snipped-for-privacy@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
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Shrug...Cant remember that. Probably the result of my stroke.
No matter. Ill fix it when I find out how.
Gunner
"First Law of Leftist Debate The more you present a leftist with factual evidence that is counter to his preconceived world view and the more difficult it becomes for him to refute it without losing face the chance of him calling you a racist, bigot, homophobe approaches infinity.
This is despite the thread you are in having not mentioned race or sexual preference in any way that is relevant to the subject." Grey Ghost
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Open the file containing your sig in "edit" mode.
Insert <hyphen><hyphen><space><carriage return/enter> as the first line of the file.
(Re)Save the file.
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BTW - that line should only contain 3 characters...
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Ok, and this does what to my sig?
Gunner
"First Law of Leftist Debate The more you present a leftist with factual evidence that is counter to his preconceived world view and the more difficult it becomes for him to refute it without losing face the chance of him calling you a racist, bigot, homophobe approaches infinity.
This is despite the thread you are in having not mentioned race or sexual preference in any way that is relevant to the subject." Grey Ghost
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