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Thread: Frame Forum: How to cut a design out of blank lugs

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    Default Frame Forum: How to cut a design out of blank lugs

    Cutting Blank Lugs

    The sales pitch: I am starting a subject thread on how to cut designs out of blank lugs. Many of my framebuilding class students have some kind of artistic background and want to find another way to express their creative talents. Carved lugs – whether the design is very simple or complex - can add beauty, personally and individuality to a custom steel frame. Using the same lugs as everyone else can be boring. The same principles I’ll explain here also apply for making a head badge or modifying any lug.

    Their history: There were a number of classic British and other European framebuilders that used some kind of cut-from-blank lugs in the past. The most famous is Hetchins. Information about its history, models and lug cutters can be found here: <www.hetchins.org> Often the British advertised their advantage as a stress-relieving feature that better distributed the load to prevent breakage. I suppose this provided a rational cover to buy something elaborate. European lug companies offered a variety of models with more complicated patterns. Probably the most famous example is the Nervex “Pro” lugs used on Chicago built Schwinn Paramounts.

    Sourcing supplies: The supply of blank lugs has always been sparse. The old European lug making companies like Nervex (that long ago closed) had them available on special order but few have survived to this day. The Haden lug company in England was the last supply house to make them but they too went out of business 10 or 15 years ago. Sometimes a blank set turns up on eBay for about $100. My small supply came from Ellis-Briggs in West Yorkshire England where I apprenticed in 1975. They used to have an “International” frame model with cutout lugs that was popular in the 50’s. Jack Briggs gave me the rest of their old stock. Some of my students have made some really beautiful frames from these lugs.

    Alternate methods: Today, builders that want lug decorations usually do a “bilaminate” construction. This is when 2 slip tubes are cut out and then brazed onto the main tubes and then fillet brazed together. There are several ways to do this to make these sleeves look or be like a lug. Claud Butler frames in England were made this way when lug supplies were scarce after the 2nd world war. While this is a good method, it is typically a bit beyond the skills of a beginner. It is easier and more practical to start with a blank lug.

    A new source: Just by chance I saw the Nikko company from Japan at an industrial trade show in Chicago 3 years ago promoting their bulge forming process. Back in the 70’s they made lugs for early Trek bicycles. This method is different (and much nicer) than the stamped and welded way old European companies used to make lugs. There are no lumpy seams that need to be filed away. I talked to their vice president who said they still had the tooling to make lugs although it hadn’t done it in years. I convinced him to make some blank ones. It helped that I had taught in Japan in between getting my teaching degrees and remembered some Japanese. It has taken some time, but with Kirk Pacenti’s help, I now have a bunch of Nikko blank lugs in standard and oversize diameters as well as the more typical pointed shaped sets in my shop. These are for sale. Write me for details.

    My interest in cutting out lugs: I became interested in cut out lugs when I bought a Hetchins frame in London during a bike tour of England when I was in college. Adding beauty to function really appealed to me and was the foundation motive in my desire to make custom bicycle frames. Over the years I’ve developed and refined methods of how to design and cut out blank lugs. I’ll share those methods with you here.

    Index of future posts: I’ll have separate postings on: 1) pictures of some historical examples, 3) an outline step by step of how to cut out a blank lug, 4) a list of the tools needed, 5) how to create a design, 6) how to apply the design to the lugs and 7) how to cut out the lugs.

    One of the advantages of a group discussion is that others can bring improvements and/or variations to proven methods.

    A quick overview of the procedure:
    1. A rough sketch is drawn onto the lug to get an approximate idea of what looks right.
    2. A flat blank outline shape of the round sections on each lug is cut out from a piece of paper. This results in 6 outlines for 3 lugs.
    3. These blank outline shapes are doubled in size and traced onto graph paper.
    4. A design is created at least twice its actual size within the blank lug outline traced onto graph paper.
    5. Centerlines are drawn or scratched onto the lugs to establish where the design should be placed.
    6. The design is xeroxed back to actual size onto some kind of sticky backed paper (that can be bought at hobby, art or drafting supply stores) or masking material (available at sign shops) and placed on the lug.
    7. Round shapes and saw blade access holes are drilled out. A jeweler’s saw cuts close to the lines and Swiss needle files (primarily) are used to file to the line.

    Here are a few pictures of lugs my students have cut out in framebuilding class. The 1st set sitting on the table is Noah’s. The 2nd picture in the fixture are Richard’s carved lugs. And the last two pictures of Art Deco lugs already brazed into a frame are Amanda’s (check out her nice clean shorelines!).
    Unknown-1.jpgUnknown.jpgUnknown-2.jpgUnknown-3.jpg
     
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    Default Re: How to cut a design out of blank lugs

    Cool! If there is enough interest we can move this to "The Knowledge".
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    Default Re: How to cut a design out of blank lugs

    IMG_0199.jpgIMG_0202.jpgIMG_0205.jpgIMG_0210.jpgIMG_0214.jpgIMG_0223.jpg
    Here are some examples of British frames made after WWII to the start of the American bike boom. The yellow and red frame in the 1st picture was made and painted by Ellis Briggs (where I learned) around 1953. These lugs did start out as blanks but the design was created by a punch press that had 17 (if I remember right) different shapes.

    The 2nd picture is a blue and gold Hetchins made in 1969. They used Latin to name their different models. This fairly simple design – called the Vade Mecum I – sometimes had a variation – called the Vade Mecum II – with with a wing or hook on each side of the main point.

    The 3rd picture is a blue Hetchins made in 1973. It is there Spyder model that came about after there Latin series. It was created by splitting and curling the points of a normal lug. Its invention was probably created out of necessity since their supply of blank lugs was getting low.

    The 4th picture is of a maroon Johnny Berry. It was made for a show in 1953. After he passed away I bought a lot of his shop back to the States. His main bench vise is still my primary vise. I particularly like the way the the fleur-de-liss are attached to a webbing.

    The 5th picture is a Claud Butler frame painted with brown primer. It was made in 1949. After the war his frames were some of the most desired in England. Actually he employed a number of builders who went on to be well know on their own like Les Ephgrave, Bill Hurlow, Ron Cooper, etc. This is an example of bilaminate construction where 2 slip tubes are cut out and fillet brazed together with the tubes.

    The 6th picture is of a set of Hetchins magnum opus lugs. It was their top-of-the-line model. They welded a punched out extension on the end of the lug. The side pieces were fork crown extensions. They sometimes used similar pieces around the brake bridge or on the seat stays by the binder bolt.
     
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    Default Re: How to cut a design out of blank lugs

    Can Nitto do these in stainless? If so how much interest would there need to be for it to proceed?
     
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    Default Re: How to cut a design out of blank lugs

    Yes, Nikko can make lugs in stainless. The challenge is that they require high minimums. I saved a long time to get the group of blank as well as pointed lugs i now have in stock.
     
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    Default Re: How to cut a design out of blank lugs

    Thanks Doug! I'm always impressed with your posts (oxycon/propane setup is going strong... looks to be about 3/4 1lb bottles per frame at my super slow pace).
     
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    Default Re: How to cut a design out of blank lugs

    doug,

    might we have some pictures of the pre-cut blanks ?

    what angles did you manage to get them in too ?

    thanks

    nathan
     
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    Default Re: How to cut a design out of blank lugs

    Quote Originally Posted by NBC View Post
    doug, might we have some pictures of the pre-cut blanks ? what angles did you manage to get them in too ? thanks
    The standard size blank sets (1" top tube, 1 1/8" down and seat tube) have a 61º down tube angle and 73º head and seat tube angles. The oversize set of blank lugs (1 1/4" head and down tube, 1 1/8" top and seat tube) have a 61º down tube angle, 72º head angle and 73º seat angle. The top/head tube lug has a 18mm extension above the top tube line as does the seat lug below the bottom of the top tube socket. All three main tube sockets are long (quite a bit longer than the old Haden blank lugs). The top of the down tube lug is an inch and a half (38mm) long and the top of the top tube lugs are almost an inch (24mm) long. The seat lug does not have any bolt clamping "ears". This makes it easier to braze on a binder bolt. It is easier to change the angles on this type of lug because they are more malleable than investment cast lugs.

    The standard shaped Nikko lugs with points (also standard size for a 1" top tube) have a 59º down tube angle and 73º angles for the lugs connecting the top tube. The top of the lug triangle shape is wider than most lugs. They look like the old stamped and welded Cinelli lugs (except much nicer). The advantage of this decent amount of space is the ability to put some kind of symbol (like the Colnago clover leaf) on just the down tube or the tops of all lugs. I used to like to cut out the customer's initial in the down tube lug if I used Cinelli lugs.

    In the picture, the OS set is in the middle
    Attached Images Attached Images
     
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    Default Re: How to cut a design out of blank lugs

    A general outline of how to cut out a design in blank lugs


    1) A rough sketch is drawn onto the lug with a pencil and perhaps enhanced with a pen to get an approximate idea of what would look good.

    2) The design is refined on a sheet (or sheets) of graph paper. Each lug has 2 design sets, one for each tube socket. For example a down tube lug needs a design for the down tube socket and a second one for the head tube socket.

    3) The round section of each lug socket is made into a flat blank rectangular outline shape on paper. It is within this template your design will eventually be drawn. The top of this rectangular outline is the wavy miter shape. This looks like the miter profiles that can be printed and wrapped on a tube to assist in hand mitering. The distance between this top miter shaped line and the straight line on the bottom (representing the lug opening) is the length of the lug socket. The outside circumference of the lug determines the width of this blank pattern. The width lines may taper a bit because a lug is slightly thicker in its middle than on its end. This taper allows the lines on each side to just meet together on the underside of the lug along their entire length when it is wrapped around the lug.

    4) The blank outline pattern can be refined by cutting it out and rolling a trial piece around the lug and nipping a bit off here and there to more closely match the lug’s intersecting shape. Folding it in 2 makes cutting it evenly on both sides easier. The pattern should end right where the one socket starts to transition into the other socket. The goal is to have this entire round lug section just covered with this paper without any of it overlapping or going beyond its area.

    5) It is extremely helpful to create your design on this outline pattern when it is at least twice (or more) the actual size of the lug. This makes it much easier to draw with drafting tools, get all the proportions just right and make things even. Small changes on a big pattern are easier to manage and don’t effect to the overall design as much. A) The outline shape can be doubled in size on a copy machine.

    6) The lug design is drawn and revised on the graph paper – keeping it within the outline shape. A) I like graph paper that has an isometric grid with diagonal cross hatches as well as boxes. Having dominant and recessive lines also makes it easier for pattern placement and design creation. B) With some cheaper paper it is helpful to trace the lug outline on the backside of the paper so erasing mistakes won’t bother it. C) Trace the blank outline onto the graph paper. Be sure the center of the blank outline is on a dominant vertical line so it is much easier to balance the left and right side equally. It helps to also put the bottom line on a dominant horizontal line.

    7) Create your unique lug design within the traced outline. A) Draw a corresponding 2nd line 9 or 10 mm actual size (18 to 20 mm on a double sized drawing) from the miter line. This matching line can help you better visualize your actual working space since you aren’t going to cut too close to the lug’s junction. B) It is important that centerline points or lines be added to your design to help position it correctly on the lug. Sometimes other points can help locate circle centers to make them easier to drill accurately. C) When you are satisfied with your creation, the lines can be drawn in more heavily to make the easier to copy. B) To get an equal design on both sides, it can be folded in half and traced or copied, flipped and traced.

    8) Your finished design is xeroxed onto some kind of sticky backed paper (like Avery “Clear Sticker Paper” reference # 53203). This is how the lug design is applied to the lug. Of course the copy machine is set to reduce its size 50% so the drawing is back to the lug’s actual size. A) It is going to take some trial and error with plain paper to make sure the position of the original pattern in the copy machine places the copy where you want it to be on the sticky backed paper. B) Clear packing tape can be placed over the design to help prevent smudging. C) The outline pattern (the original blank shape) is cutout to be placed in position on the lug.

    9) Centerlines are drawn or scratched onto the lugs to establish where the design should be placed. A) This is most easily done on a flat table with the help of a surface gauge and other accessories. B) I use 2 identical lugs with the through tubes (like 2 head tubes) held off the table on 4 identical blocks. A top tube or down tube connects the 2 lugs together. Now all the tubes and lug centerlines are in the same plane. C) A machinist square or block can make a mark on the side of the tube (in reality its top) when it is rubbed against it. D) The point of a surface gauge can be adjusted to be in the middle of this scrapped mark and then scratch a centerline around all the center of the lug or lugs. The Nikko blank lugs already have some centerline marks in some places that can be extended. In this case the surface gauge can be set to the lug’s marks.

    10) The design is positioned on the lug by matching centerline marks and the bottom line of the outline to the socket opening. Of course the protective backing paper has to be removed first.

    11) The lug shape is created by sawing and filing following these basic procedures: A) Cut close to but not exactly on the line with a jeweler’s saw (because the blade can rarely be 90º to the line). I typically cut with #2/0 blades for fine work and the more course #1 or greater for hogging material away. Expect to break a lot of blades until you get the hang of it. B) File to the edge of the line with Swiss round handled needle files (sometimes called jeweler’s files and not to be confused with Swiss pattern files). Of course bigger files can be used if they fit within the design’s lines. I use the more course #0 cut jeweler’s files. C) Use a drill to open up round shapes and to also create saw blade access holes (especially in windows). D) Work from the edge of the lug opening inwards. It is best to do the finish filing to the line before going very far inland (rather than roughing out more of the design behind it) because the unbothered back portion can provide more support when cutting and filing. The details of a design can get pretty flimsy if it is all cut out first and then finish filed afterwards.

    12) After the design is completely cut out and filed to the lines, what is left of the design pattern paper can be removed. Any imperfections can now be more easily seen and corrected. I use emery cloth to get rid of the sticky backed paper.
     
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    Default Re: How to cut a design out of blank lugs

    Tools to Design and Cut Out Lugs

    For creating the lug design:

    Graph paper. This is paper with printed box lines. They come in various grid sizes and paper quality. Almost any graph paper will work. Smaller grid boxes make it easier to find and establish key design points. I also prefer when the grid periodically has some heavier lines every so often (like every inch) to more easily establish a centerline and base line and locate various key points of the design within a grid box. My favorite is made by the Alvin company and has got a heavy rag content so it can be erased many times. It also has some see-through quality for tracing. Not only are the background boxes small with heavier lines every inch but it also has diagonal crosshatches called an isometric grid. This makes the placement of the mirror image on the other side easier. It is called Alva-Line Isometric Grid. It is described on the cover as 16lb medium weight blue-white tinted tracing paper. A 50-sheet pad cost me $24.25! It was worth it for me. Your can read about it here: Isometric Grid Pad 8.5" x 11" - Alvin & Company

    IMG_0225.jpg

    Drawing tools that can be bought at drafting or office supply stores, bookstores and art and hobby stores. I keep a supply of sharpened #2 pencils. Pentel makes a “Clic Eraser” model ZE-21 that works much better than the erasers on the end of a pencil or eraser lumps for school kids. I like to use clear (12”/30mm C-Thru #36) as well as small stainless steel 6” rulers. One of my favorite rulers for marking length is made by the General Company. They are called Flexible Marking Rules and come in 6” and 12” lengths. You can buy these stainless steel rulers from the Reid Supply Company. They have little slots in the ruler by each length mark to guide the pencil lead. French curves can useful as well as those tracing plastic templates with oval (with various ellipse degrees) or round or other shapes. They are made by the Pickett, Staedtler and Helix (and other) companies. I keep a pencil sharpener handy. A compass can help keep webbing lines equidistant. (The steel point follows the 1st line while the pencil makes a 2nd line however far apart the points are set.) A machinist divider is similar except it has 2 steel points instead of a pencil on one side for marking 2 lines equidistant apart as they curve together.

    IMG_0230.jpgIMG_0229.jpg
     
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    Default Re: How to cut a design out of blank lugs

    A light box. This is used to trace designs from one piece of paper to another. I use a small florescent light under a piece of glass held up by some short pieces of wood. Paper held to a sunny window works too.

    Access to a copy machine that has increasing/reducing size capability. The original lug outline shape (created from being wrapped around a socket) is traced onto a piece of paper so the outline can be doubled in size on a copier. This twice-sized outline is traced onto graph paper lining up center and base lines. On this paper your design is created. When finished it is xeroxed back to actual size onto adhesive backed material.

    A Herbie Helm or similar lug vise.

    IMG_0239.jpg
    In picture one I use a piece of frosted glass from my sandblaster window to help make a light box. Graph paper is positioned over a double sized Nikko blank lug down tube socket outline. It is ready to be traced. The image you see is the outline shinning through the top piece of graph paper.
    IMG_0240.jpg
    Picture two shows the copy/tracing sequence to create an outline ready to draw a lug design. The 2 lug socket patterns (one still wrapped around the lug) are in the upper left. Beneath the lug is the same lug pattern and its tracing ready to be copied. On the right on top is the doubled size Xeroxed copy from the left outline. Below it is the same pattern traced onto graph paper (where a lug design can be created).
    IMG_0241.jpg
    In picture 3 is a Nikko pointed lug on a Herbie Helm stainless steel lug vise.
     
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    Default Re: How to cut a design out of blank lugs

    Tools continued:

    For creating centerlines on lugs:
    A very flat surface. A surface gauge. 4 evenly sized blocks like 1-2-3 machinist blocks. 2 head tubes. 1 down and 1 top tube. A machinist square (or another machinist block or something with a sharp edged right angle). The blank Nikko lugs do have some centerline marks already that can be extended.

    For placing the design on the lug:
    Drafting supply stores sell a kind of shiny clear or milky opaque paper (they have both) that has an adhesive back protected by backing paper. They usually cost a bit more than $1 a sheet. It is often referred to as “sticky back” paper. The official name is chart pack Applica film. Office supply stores sell something similar for labeling and hobby stores for scrapbooking or whatever. All of these materials have an adhesive on one side that is protected by backing paper until it is removed for use. Avery makes a “Clear Sticker Paper” for ink jet printing. Their reference number for a 3-sheet pack is 53203 ($6.60) and for a 10 sheet pack is 4383 ($13.60). They also make a similar white “Sticker Project Paper” that comes in either a 5 or 15 sheet pack. White paper works but it is more difficult to line up with lug centerline marks. Staples has a “matte white sticker paper” that comes in a 30-sheet pack. Their reference number is 70972 and costs 13.99. This paper is a bit sticker than the Avery. I also found at Hobby Lobby a product made by the Grafix Company called Rub-onz transfers – which is a two-part product. The clear/matte transfer sheet doesn’t have any adhesive so it can go through copiers or printers easier. Its separate partner sheet has a transfer adhesive between the two cover sheets. One is taken off to place it one the design sheet (after it has been created) and then the other side is taken off to put it on the lug. There were 4 sheets of each type and the package cost $9.99. Sign companies have a variety of materials (either for masking or for making signs) that also have some kind of adhesive back. They can custom cut an 8 ½ X 11” sheet of this masking material. After the design is xeroxed onto the material and cut to shape, the backing paper can be removed so the adhesive side can be placed on the lug.

    Clear packing tape to put over the Xeroxed design to keep it from getting smudged while cutting out the design on the lug.

    Good Scissors and perhaps an Exacto knife.

    80 grit 1” wide emery cloth (called industry or production cloth in sales catalogs) to remove the material that placed the design on the lug for final inspection and correction.
    IMG_0227.jpg
    Picture one shows 2 types of clear transfer sheets with adhesive that can be Xeroxed, cut-out and placed on the centerlines of a blank lug.
    IMG_0232.jpg
    Picture two shows the tools and setup to scratch centerlines on lugs. 2 head tubes hold lugs off the table with 4 blocks that are the same. A top tube connects the 2 lugs putting everything in the same plane. Rubbing a 1-2-3 block against a tube creates a centerline. The pointer of a surface gauge is adjusted to the center of the rub mark (or set to the centerline mark already on a Nikko lug) and a centerline can be scratched everywhere around the lugs.
     
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    Default Re: How to cut a design out of blank lugs

    Tools for cutting out the lug:

    1) A drill with various sized drill bits. Drill bits with a 135º tip angle don’t wander off center on thin tubing as much as the more standard 118º tip. 2) A center punch. There are some that don’t require a hammer to make a mark but rather just push on the mark and it will snap to leave a little indent. Otherwise you will need a small hammer to smack the center punch.

    A 2 ¾” (+ or -) jewelers saw (the depth from the blade to the back of the saw frame) + dozens of 2/0 jewelers saw blades + some more with courser teeth. Some saws have greater depth for cutting bigger sheets of material but the smallest ones work fine for lugs. A certain model could very in size a little from 2 ¾” (which of course doesn’t matter). My very favorite is the very light and stiff (and expensive) Knew brand but even the cheap $10 ones work fine for me. I like a model that can adjust to the length of a broken blade and tightens the blade at the south corner of the saw body’s rectangle (some are a fixed length and use the flex in the saw body to tighten the blade). I don’t find the ones that have a tightening screw above the blade or that can hold a blade at some other orientation to the saw frame particularly useful.

    Jewelers saw blades come in many makes and varieties. They are usually sold by the dozen or gross (12 dozen) because they are easy to break. I always bought Herkules blades but jeweler’s catalogs like Gesswein have several good brands to choose from.

    Round handled Swiss needle (jewelers) files (not to be confused with Swiss pattern files) come primarily in 3 different lengths, 12 different shapes and various cuts. They are often sold in a set of 12 but they can be bought individually. The courser 0 cut makes the most sense to get since you want to remove metal and not polish it. Mostly I use just 3 of the 12 available shapes. For concave curves I like the file that is shaped like a half round file except the flat side has a safe side (meaning it doesn’t have any teeth). This is called a marking file. This makes it easier to file in tight corners because the back isn’t catching on the other side. For convex curves I like using a file that is triangular in shape except only the widest of the 3 surfaces has teeth. The triangle back has safe sides. It is called a Barrette file. This shape gives it more stiffness than a flat file and also allows it to get into tighter places without the back scraping the other side of the design. And for circles I like a round file. Other shapes I occasionally use are a knife file for lengthening triangular cut out points and a crossing file that has a different half round radius on each side. Of the 3 lengths I find I use the middle 5 ½” lengths by far the most. The 4” lengths are for really small tight places (but they are too small for general use) and the 6 ¼” can hog off the most material (but is a bit big to get into some tight curves). I use all of them sometime but if I was on a tight budget I’d only get the 3 I’ve mentioned with a 0 cut and are 5 ½” in length. Other standard files can occasionally be used when hogging off more material. I like either the Nicholson or Grobet brands. The cheap import brands don’t seem as sharp or keep their sharpness as long and are thicker.

    Very occasionally I use a Dremel or Foredom or some other power tool. I find they take off too much material too fast and it is easy to make an unrepairable mistake with a slight slip up.
    IMG_0237.jpg
    Picture one shows 4 different jewelers saws. In the top left corner is one sold by the E-xcto company (found in hobby stores). It has a wing nut to tension a blade. The red one is made by the Knew company and is very light and stiff. It is the best but also by far the most expensive. The one in the lower right is also very light but requires flexing the body when attaching blades to take up any slack. This is a bit of a nuisance if the blade needs to be put through a lug hole before tightening. On the SW corner is my original saw I bought when apprenticing in England. Blades are tensioned by pushing on the saw frame and then tightening a wing nut.
    IMG_0236.jpg
    Picture two shows examples of Swiss pattern needle files. The ones below the ruler are the 3 shapes and 5 ¼” length I use the most. The top one is a Barrette file that is flat on one side and triangular without teeth on the other. The middle one is round of course. The bottom one is a Marking file that is half round on one side and flat without teeth on the other. The advantage of having a “safe” side is that it doesn’t get caught when filing in tight places. The 2 files above the ruler illustrate a 4” length and a 6 ½” length.
     
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    Default Re: How to cut a design out of blank lugs

    Tips for Creating the Lug Design

    1. A rough sketch is drawn onto the lug with a pencil and perhaps enhanced with a pen to get an approximate idea of what would look good.

    2. You want to create and refine your lug design on a sheet (or sheets) of graph paper. Each lug has 2 design sets, one for each tube socket. For example a down tube lug needs a separate design for the down tube socket and another one for the head tube socket. Graph paper has a bunch of horizontal and vertical lines (that make little boxes) and sometimes diagonal lines to help assist in drawing your design.

    3. The round section of each lug socket is made into a flat blank rectangular outline shape on paper. It is within this template you will eventually draw your lug design. The top of this rectangular outline is the wavy miter shape. It looks like the miter profiles that can be printed and wrapped on a tube to assist in hand mitering. The distance between this top miter shaped line and the straight line on the bottom (representing the lug opening) is the length of the lug socket. The outside circumference of the lug determines the width of this blank pattern. The width lines taper a bit towards the bottom because a lug is slightly thicker in its middle than on its end. This taper allows the lines on each side to just meet together on the underside of the lug along their entire length when it is wrapped around the lug.

    4. The top miter line of the outline can be refined by rolling a cut out trial piece onto the lug and nipping a bit off here and there to more closely match the lug’s intersecting shape. Fold the design in half to cut the offending extra away evenly on both sides. The goal is to have just this entire lug section covered without any of it overlapping or starting to creep into the lug’s transition to the other socket. This refined outline shape can now be retraced onto clean graph paper. Make sure there is a stronger vertical line in the center and horizontal line along the base of the outline. For convenience, I put all 6 outlines on one standard size piece of graph paper. It can help to enhance the outline tracings to make them easier to copy. They are now ready to be copied again.

    5. It is extremely helpful to draw your pattern at least twice (or more) the actual size of the lug. This makes it much easier to create your design with drafting tools and get all the proportions just right. Small changes don’t make as radical a difference. The outline shape can be doubled in size in a copy machine and then traced back onto the graph paper where the design will be created. Be sure and square the outline with the lines on the graph paper. You want its center and base to be on a more clearly dominate line. Sometimes it is helpful to trace the lug outline on the backside of cheaper paper (if that is what you have) so erasing mistakes won’t affect it.

    6. Create your unique lug design within the double size traced outline. Start by drawing a corresponding 2nd line 9 or 10 mm actual length (18 to 20 mm on a double sized drawing) away from the miter line. This inland matching-the-curves-of-the-miter line can help you better visualize your actual working space since you probably aren’t going to cut in too close to the lug’s junction. The curves in this line will probably influence the placement and shape of the curves in your design. You might want to make it a dotted line.

    7. Creating a good design is about getting the right proportions for the space available on a lug. And the limitations of how fine a pattern a jeweler’s saw can cut. Typically you don’t want all the design to be on the outside edge of a lug leaving too much blank space behind it or it won’t seem balanced. It can really help to have windows. Neither can the design be overly complicated or too small. One of your biggest challenges is going to be that the space available on the top of each lug has a different amount of real estate. This probably requires modifying the size and/or shape of each design on each lug so they appear matched when grouped together (since they can’t be identical).

    8. It is important that centerline points or lines be added to your design to help position it correctly on the lug. The base line of the outline will be matched to the end of the lug’s opening. Sometimes other points in the center of a circle can make them easier to drill accurately (so you don’t have to guess where to position the center punch to leave an indent for drilling). Other distinctive points (like the tip of a fleur-de-lis) can help in creating the mirror image on the other side of your design.

    9. Once the design is drawn to your satisfaction, it can be reduced to actual size and printed on sticky-backed paper by a copy machine
     
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    Default Re: How to cut a design out of blank lugs

    Quote Originally Posted by Doug Fattic View Post
    Tools to Design and Cut Out Lugs

    For creating the lug design:

    Graph paper. This is paper with printed box lines. They come in various grid sizes and paper quality. Almost any graph paper will work. Smaller grid boxes make it easier to find and establish key design points. I also prefer when the grid periodically has some heavier lines every so often (like every inch) to more easily establish a centerline and base line and locate various key points of the design within a grid box. My favorite is made by the Alvin company and has got a heavy rag content so it can be erased many times. It also has some see-through quality for tracing. Not only are the background boxes small with heavier lines every inch but it also has diagonal crosshatches called an isometric grid. This makes the placement of the mirror image on the other side easier. It is called Alva-Line Isometric Grid. It is described on the cover as 16lb medium weight blue-white tinted tracing paper. A 50-sheet pad cost me $24.25! It was worth it for me. Your can read about it here: Isometric Grid Pad 8.5" x 11" - Alvin & Company
    For those of you that are truly cheap or don't want to wait for shipping, there's a PDF graph paper generator online -- pick the type of graphing (including isometric), size, scale, etc. and then it generates a PDF that you can print on-the-spot.

    Print Free Graph Paper
    Ita erat quando hic adveni.
    www.danbailey.net
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