Copyright (C) 1986-2008 by Daniel H. Hudgins, All Rights Reserved.

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This Web site is dedicated to the thousands of "users" of my programs, those who have helped test my programs over the last 22 or so years, and especially those who shared their experiences with me.

You must read this notice: This is a licensed Web site (HTML document and associated files). You must read and agree to be legally bound in contract by the Terms of Use and conditions given in the End User License Agreement ("EULA"), Legal Notices, Instructions, Warnings, Disclaimers, and all other text in "SECTION: 0" of "This Web Site" (HTML document and associated files) before reading or using any of the information, software programs, and or files, contained in, linked to, and or associated with, "This Web Site" (HTML document and associated files). Any use or "Beta Testing" of "This Web Site" constitutes your acknowledgment of your full agreement with the current End User License Agreement ("EULA") and your decision to have this current license supersede all prior and contemporaneous agreements and understandings. Information and files in "This Web Site" (HTML document and associated files) have been placed here so that long time users of "The Author's" programs DANCAD3D.COM (tm) , DANCAM.EXE (tm) , or DANPLOT.EXE (tm) could help proofread the text of the documentation files or screens displayed, and also help test data files, example files, and or any software programs that might be made available from time to time, to aid "The Author" in finding mistakes, bugs, and other errors, omissions, defects, mistakes, and faults. Everything in "This Web Site" (HTML document and associated files) is "Beta Test", "Beta Code", Experimental, Preliminary, requires proofreading, or is being evaluated for possible revision, and is NOT warranted to be free of defect. To help "The Author" report any bugs, foul-ups, defects, or mistakes that you find, see "SECTION: 8" for instructions. "This Web Site" (HTML document and associated files) and all other files and programs by Daniel H. Hudgins are made available "AS IS" without warranty of any kind express, expressed, or implied. All offers and specifications are subject to change or discontinuation without notice of any kind. Please read "SECTION: 8" of "This Web Site" (HTML document and associated files) before trying to contact "The Author."

SECTION: 7.20 is for some "general" discussion about Metalworking, see also the program files in the current distribution of my programs, the other parts of this HTML documentation, and the current On-Line version of this Web site for information more specifically about my programs. Any comparisons of my programs or methods to some others is only given as a vague generality of my opinion and is not intended as a recommendation or reference to any particular products, or methods, always make your own evaluations and comparisons before taking any action.

The illustrations in the sections and sub-sections of SECTION: 7.20 are not intended to be examples of recommended or proper practice, and in some cases may illustrate methods that you yourself would not apply as shown. The variety of illustrations, showing both practical and discouraged practices, has been included to provide illumination of the general metalworking principles discussed in these sections, and other parts of the documentation, in order to help the reader understand some of the many issues relating to the practical matter of producing parts of usable quality by manual, semi-manual, semi-automated, or fully automated machine operation, and how CAD and CAM software, such as my programs that are described in this Web site, might be of assistance to that end.

A couple of the photos in subsections of SECTION: 7.20 where taken using a Sears (tm) Craftsman (tm) Atlas (tm) type lathe, the others were taken while using a ShopTask (tm) model 17-20 type 3-in-1 multi-purpose combination mill, drill, and lathe. When a manual machine tool is retrofit for computer control you need to consider how safety shields should be added, and where the emergency power cutoff switches should be placed.

Be sure to watch all of the video clips linked to in SECTION: 4, in order to see my CAM program DANCAM.EXE (tm) being used to automatically make a part under a form of Computer Numerical Control a.k.a. CNC, and to also see other narrated lessons on how to use my CAD program DANCAD3D.COM (tm) for related tasks.

When making parts, whether by manual or automated means it is frequently necessary to make layout marks on a part so that you can locate the part for setup in the machine or to position the tool for cutting.

Rather than looking at a part drawing on paper and re-drawing layout lines onto the part covered with blue layout die by the use of a sharp metal scribe, you can use a CAD program, such as DANCAD3D.COM (tm), to draw the points or outlines that need to be marked, cut the pattern out with scissors or a razor, tape or glue the printout onto the part, and use the printout as your guide to marking or cutting.

A CAM program, such as my DANCAM.EXE (tm) or DANPLOT.EXE (tm) may be used to plot markings directly onto the part from the lay out pattern drawn in the CAD program.

So you see, even if you do not plan to have the cutting done in an automated machine, the CAD and CAM programs can be used to assist in marking parts to help you get accurate results, even on odd shaped parts that might be difficult to lay out by using a compass, square, and straightedge.

When making a layout pattern drawing for attachment to the part, you only need to draw the essential details. In this case the layout pattern is to be wrapped around a cylinder, so the X axis is drawn as PI, e.g. 3.141592654, times the diameter of the cylinder, with the lines extending at one end for some overlap to get the alignment between the points to be marked, i.e. avoid cutting the layout pattern through the points to mark, cut between them.

You can measure the CAD print out to make sure that it is printed out to the correct dimensions. In my CAD programs DANCAD3D.COM (tm) and DANCAD87.COM (tm) you can use the printing scale to adjust the overall size of the printout, and the Magnify command to adjust the vertical and horizontal dimensions separately.

My CAM program DANPLOT.EXE (tm) can be used to operate a large "home made" pen plotter that can then be used to draw layout drawings full size for transferring of the layout to large parts. You can build a plotter ten or more feet long if you want to since DANPLOT.EXE (tm)'s configuration menu lets you install the values for "any" size automated machine. DANPLOT.EXE (tm) can also be used to plot the layout markings directly onto the parts themselves, or to move the cutting tool around and do the cutting without having to do any layout.

Once you get the printout to the correct dimensions, you can cut the layout portion out and tape or glue the printout onto your part. In this case the bottom line of this pattern was used to align the pattern with the end of the cylinder (bottom end in the photo), and the pattern was made a little short so that the tape could lay flat near the "stem" end.

Normally you would use a magnifying glass and a center punch to mark the points to drill at on the part. However, in this part the metal was too thin to hammer on without causing distortion, so I used a small lathe center drill to enlarge a small "prick" made by hand pressure using my carbide tipped scribe.

The lathe type center drill is better for such marking because it has less tendency to flex and walk off the line than a wire thin regular drill.

In a CAM machine a center drill can be used to go around and mark the start of the holes before a larger drill is used to drill the holes in order to not have to center punch the drill points.

Here you see a pattern used to layout a "bolt circle" onto a cap for a cylindrical casing. I used a quarter inch hole punch to punch four holes into the pattern and put masking tape over the holes, I find that this method works better than taping at the edges since the pattern cannot slide much when taped on to the flat surface through the punched holes.

When a disk is faced on a lathe there are visible tool marks that make concentric "circles" and when the tool is set to the spindle axis height you can cut so that the center is visible on the surface. The small hole at the center was used along with the straightedge to align the pattern onto the center mark on the part, as a double check for the alignment of the outer line that was cut along with scissors.

I used the magnifying glass to help locate the tip of the carbide scribe on the points to mark, and then again to locate the center punch in the prick made by the carbide scribe.

Here you see a pattern used to layout another "bolt circle" onto a part. Notice that four holes where punched and had adhesive tape applied over them, then the layout pattern was placed over the part, adjusted for centering, then pressed down to stick.

Be sure that you mark all of the points that might need marking before you peel off the printout, since it is almost impossible to get the pattern back on a second time and come within 0.002 inch of the first time.

On smaller parts I usually use a small sharp scribe to poke through the paper before I use the carbide tipped scribe to prick the metal part, since once a small hole is in the paper, the paper helps keep the scribe and center punch from slipping off position. With the carbide tipped scribe I have found that rocking it in a circular motion while applying pressure makes a good indentation without having to hammer on the scribe. After there is an indentation the optical magnifier can be used to locate the center punch, and the center punch can be tapped on with the lead hammer to make a dent large enough for a small drill to stay in.

Unless you have an rotary indexing device, drilling evenly spaced holes on the outside of a ring can be a layout problem. With my CAD programs, you can just draw a layout pattern, wrap the layout pattern around the part, and mark through the pattern.

Another advantage of using the CAD layout patterns is that you may not need to scratch lines into the part, just prick marks where the holes will be drilled, or material will be removed anyway, so the part is not blemished by layout scribe lines.

To make this lens mount I needed to mark for tabs on the circular flange, and one of the tabs had to have a slot in its center. To lay this complex pattern out I made a CAD layout drawing, printed the drawing, then carefully cut the pattern out so that I could slip it over the part and scratch the boundaries of the tabs and slot with a small sharp scribe.

If you look closely you can see that there is about a sixteenth of an inch of paper around the center of the pattern, that fit snugly around the part, and was also needed to mark the arcs of material to be left on since the bottoms of the cutouts for the tabs where parts of a circle, and not flat. The slot in the key tab was to be marked to a different depth from the spaces between the tabs.

Once I had the scratch lines on the part it was a simple matter to mill away until I was near the scratch lines, and then check the actual dimensions with a dial caliper. The final dimensions were arrived at by using some fine tooth needle files, which were also used to remove burrs and bevel the sharp edges a little.