Together, we are the strongest mastercam community on the web with over 56,000 members, and our online store offers a wide selection of training materials for all applications and skill levels. Jan 14, 2016 the rule of thumb for me for material call out is thickness x with x length and this also translates into st x lt x lg. The soundpost and bass bar are usually equidistant from the respective edge of bridge foot. Fitting a sound post patch the first priority for the luthier is to close the. Saran wrap now is a good time to change the cellophane wrap that separates the top from the cast and brush the cast to make sure there is no particulate on it before lightly clamping the top to the cast. Second question how does grain direction affect this. The comparison is made between the soundpost position at 517 and the other two in turn. Grain line moves opposite to cutting direction with care, you can move the grain to create a pattern you like or to make it coincide with other features. Also the maple back might need restoration of a soundpost crack. The actual failure of a column is an instability due to lateral deflection under compressive end load. Grain sound sound effects grain sound sounds pond5. Material dimentions and the grain direction industrial.
Some granites have veiningpatterns that run in the short direction, so thats the way they look when you fabricate the tops theres nothing that can be done about it. Aug 23, 2010 granite slabs are typically around 5 x 1012, so they really only get fabricated in one direction otherwise you end up with seams every 5. Paper grain direction and cardboard grain direction. Its good to have a new piece of wood covering the cracked area with a slightly altered grain orientation, effectively laminating the top in that sensitive area. You can define a grain direction to use when calculating the bounding box for sheet metal parts. Using the proper grain will ensure a quality job, not only in looks but in durability. How to specify brushed finish grain direction solidworks. Sheet metal grain direction coil direction computer.
Material dimentions and the grain direction join us. So, from time to time we need to show the direction of the grain on sheet metal parts. This is a delicate repair and the only way to save the top of a beloved instrument once this has occurred to ensure the crack will not reopen. Straight split spruce with grain tighter than the top. Rip a piece of paper and youll notice that it tears very easily, and very straight, in one direction, yet quite messily in the other. All paper, when it is manufactured, has a grain in which the paper fibers are laid down. If i pet him from head to tail, my hand passes smoothly along his fur with no friction. The lengthwise grain and crosswise grain are both regarded as straight grain, sometimes called straightof grain. Pages may also resist turning if the grain direction is wrong. Sheets have been rolled, either hot or cold rolled. The top ill cleat with the usual small,thin spruce square with its grain 90 degrees to the plate grain. Mechanical properties are also used to help classify and identify material. If youve forgotten your password or username, email madfiddler link on the left of page.
The reason a soundpost patch is such a cause of concern is that while the crack looks like just a tiny scratch, its in the most structurally stressed part of the instrument, subject to constant pressure and movement. A patch is a more invasive procedure, but the location of a crack in the soundpost area necessitates its implementation. The grain of the studs runs perpendicular to the grain of the violin in order to. Every board has grain direction and its a natural feature of wood that woodworkers need to become intimately familiar with. How does grain direction in carbon steel plate affect. Some pegs need rebushing with identical maple and grain direction to avoid further deterioration of the already heavily damaged scroll. Continue the line up both sides of the spruce and onto the top of the plywood. Ive repaired a large crack in the back plate and one in the top plate. For the s275 j2 it has been tested in the transverse direction at 20c. Based on the equipment, your project and our expertise, will select the proper grain direction of.
The balance of the strings is affected by this distance. Grain direction article about grain direction by the. On this patch i also made the center of the patch line up with the crack which is the thickest part of the patch and therefore the strongest. Download and buy high quality grain sound sound effects. Page 3 of 6 a signed version of this document is available at the quality procurement department of fokker aerostructures unless indicated otherwise for each program agreement, the supplier shall provide all records, reports, specifications, drawings, designs, inspection and. The length and position of soundpost page 2 internet.
When repaired properly with a sound post patch, the instrument can continue to be a. I want to specify the grain direction for brushed finish of a sheet metal part and i am looking for ideas on how i should do that. When the wood is cut, these growth rings create the grain. How to read grain direction popular woodworking magazine. Kathrin repairs a broken violin philip brown violins. The set up of the violin, setting the soundpost, cutting the bridge, adjusting. If you have wrong paper grain direction, there is a higher chance of fractures or tears.
He had some 1x3 a36 flatbar that he was using for his test pieces to make up his plate sets. If left too thin, the glue can cause the grain of the top to reverse and cloud the varnish. Carving with the grain means to cut in the same direction of the wood b. Because of the irregular grain on the front of this cello it appears that the orientation was reversed but in fact the direction of growth is normal.
In order to do this ive been clicking on the view, creating a new sketch, then ive been drawing little dotted lines on a mostly blank area, constraining themin case the part changes so they will stay attached then i back out of the sketch, using a dimension style i set up for ordinate dims that has. Bowed string instruments in particular are made of a number of pieces of wood of different types and grain direction which can be susceptible to fluctuations in humidity. You, as a consumer, rarely have to worry about grain direction. With the method we chose to print slabs figure 8, the cut directions were with grain a and b and cross grain c and d, due to the concerns of anisotropic behavior, as discussed in astm d412, where the specification indicates, slabs should be cut so the lengthwise direction of the specimen is parallel to the grain direction ref. Repairing an instrument with a sound post crack triangle strings. I slightly rotated the grain on the new piece of wood relative to the grain direction on the original wood to give the cracked area more strength. It is also common for soundpost patches to suffer from glue starvation, as the endgrain of both the patch and the top wood will tend to soak up too much glue sizing helps. I often tell people that the grain direction in a board is like the fur on a cat. The grain in paper comes from how the fibers of the paper are arranged. Jun 06, 20 a quick way to tell the grain direction is by reading the package the paper came in. When just small pieces are involved, you cant say which was the rolling direction, thats why mdg said it was difficult to know. The next step was to add an oval soundpost patch to support the sound post.
Quilters refer to any cut that doesnt run along a straight grain as a bias cut. The cellist jan vogler pointed out to us that the unusual grain orientation on this cello is the same on his 1707 castelbarco, fau stradivari, which was also known to vuillaume. This was a daily project for several weeks painstakingly picking at individual fibers of old patches and clumps of. Soundpost patch on 1890 german violin a sound post patch is an unfortunate, yet common, repair with violins. After gluing the patch, it is then carved back and smoothed flush with the surrounding wood. A patch is always the best repair for a soundpost crack. When repaired properly with a sound post patch, the instrument can continue to be a reliable tool beyond your lifetime and perhaps even improve its tone.
The idea of making sure that the grain runs in the same direction when gluing boards together is certainly sound. When a top crack passes over the sound post area it is the usual procedure to. The post puts a lot of pressure on that area and the bridge puts a lot on from the other side. However, wrong grain direction makes book less usable and even leads to structural damage and early deterioration. Paper grain direction plays a big role in every printing and binding job. Apr 27, 2018 in that article i laid out the process of how to make a counter form that will help keep the pieces level and allow linen reinforcement to dry slowly in. It is split from a seasoned block that matches the grain characteristics of the top. This rib repair is different than rib cracks parallel to the grain, but the final form is the same. The cellist jan vogler pointed out to us that the unusual grain orientation on this cello is the same on his 1707 castelbarco, fau. Tearout occurs when the spinning bit encounters grain that isnt strongly supported by its own structure. Granite slabs are typically around 5 x 1012, so they really only get fabricated in one direction otherwise you end up with seams every 5. All cracks were repatched with symmetrical pieces of spruce. Gently lower the sound post into the instrument picture b. The fundamental relationships between grain orientation.
This soundpost was installed too tall, adding pressure to the violin top causing it to crack. Basically, it needed major surgery, involving taking off the lid. The trouble is though, even in one board the grains going to come back at you at some point. Our customers mbd models usually come in with grain direction as an axis system and a note specifying xl, ylt, and zst where l is length or grain direction, lt is long transverse, and st is short transverse. There will also be a separate inside form made for this repair, but we will get to that later. Sound post at 530 position the long time average spectra, ltas, for these files are shown in figures 5 and 6. Be sure to draw an arrow to show which direction the patch will be going for fitting.
The plot for no soundpost appears below that for the 517 position. At what point does the presence of significant cracks, even if well repaired and stable, diminish the value of a bass or raise a red flag to avoid it. Each old patch had to be planed paper thin a challenge due to the extremely hard, stringy fibers of the ash, then wetted and scraped out using chips of glass. Its good to have a new piece of wood covering the cracked area with a slightly altered grain orientation, effectively. The main differences occur in the frequency range below 2 khz. I recently ran into a prewar d28 that had nearly a 45degree vs. Wood that is compromised by a crack or, as we will see, worm damage, will be vulnerable as its subjected to the downward pressure of the bridge, and the upward pressure of a properly fitted soundpost.
In addition to the new bounding box sketch, there is a new option in the property manager for the flatpattern feature. To understand wood grain, or grain dynamic, think of petting a dog or a cat. As such, the direction of the grain rings in the soundpost end relative to the top grain does not affect the column strength. Bruce hoadley wrote that grain is a confusingly versatile term with numerous different uses, including the direction of the wood cells e. Most often, the grain direction is represented in the last dimension of the product description. Double bass workshop, 45 monona dr, monona, wi 2020. When just small pieces are involved, you cant say which was the rolling direction, thats why. Im in the process of repairing a very old mandolin for a friend. Now when i order material i still have to describe which one of the last 2 dimensions is the long grain because i dont expect the suppliers to abide by the same rules i do and i have seen in the past that they dont. Paper fibers follow the direction of the paper making process. With the method we chose to print slabs figure 8, the cut directions were withgrain a and b and crossgrain c and d, due to the concerns of anisotropic behavior, as discussed in astm d412, where the specification indicates, slabs should be cut so the lengthwise direction of the specimen is parallel to the grain direction ref. Despite these improvements, large inconsistencies still exist between numerically predicted mechanical behavior and what is observed experimentally. The software determines the smallest rectangle bounding box that aligns with the grain direction to fit the flat pattern.
A papers grain is the direction in which the majority of the fibers lie. Shar music instrument care and maintenance shar music. The cracks were placed in a way that the only reasonable approach i could think of to reinforce them was to remove the aluminum reinforcement shen uses underneath the fingerboard and glue in a close fitting spline. The other factors mentioned by other posters would be the reason for picking a grain. In order to do this ive been clicking on the view, creating a new sketch, then ive been drawing little dotted lines on a mostly blank area, constraining themin case the part changes so they will stay attached. Some granites have veiningpatterns that run in the short direction, so thats the way they look when you fabricate the tops. Find a grain line in the center of your spruce piece and mark the entire length of the grain with a pencil. Understanding grain direction we show you two ways to read grain direction even in rough stock that will help you get tearoutfree surfaces. If left too thin, the glue can cause the grain of the top to reverse and. Be sure to draw an arrow to show which direction the. Grain direction is an important consideration in printing processes such as sheet fed offset lithography in particular multiplecolour work, especially in connection with dimensional stability how well a particular sheet of paper will retain its original length and width upon exposure to moisture and pressure. The grain direction of each new piece of new wood was very slightly offset, in alternating directions, to resist future splitting along the grain of the top plate. The most common properties considered are strength, ductility, hardness, impact resistance, and fracture toughness.
Alternatively there will be an annotation applied to hidden geometry with a fake alphanumerical dimension of l, lt, or st. Stroke the cat or board one way and the cat will purr, and your tool will produce a nice surface. The patch wood is oriented so the grain lines up nicely with the original. The d28 had a classic mid30s voice, illustrating that grain orientation doesnt always trump all other factors. This has been a tried and true method that ive used before. There are two crucial distances in the placement of the spruce sound post. Repairing an instrument with a sound post crack triangle. I have to beleive that the grain direction of the soundpost is to provide strength. Grain direction is an essential aspect of producing a wellcrafted book. Facts about fabric grain that every quilter should know.
The fibers are typically parallel to each other across the sheet and knowing the grain direction is important when we go to fold the sheet of paper. If your instrument does happen to get a soundpost crack, theres no way. How does grain direction in carbon steel plate affect strength. Grain direction article about grain direction by the free. A shen bass came in with a nasty cross grain neck break a couple inches below the scroll. This is important to the performance of the instrument. Granite pattern and grain direction counter top, kitchen. It may seem like a small detail, yet it makes a crucial impact on the longterm lifespan of a book. Here the plaster cast gives support of the soundpost crack patch and for the newly added upper edge.
The actual placement of the soundpost using a soundpost setter is much the same a more practical experience that is challenging to put into words. This measurement can be made with a cut business card. The first is the relationship of the soundpost to the bass bar. When its cross grain you see, there is more directions for the. The grain orientations in standard wrought forms of metallic products are shown the image.
Ifwhen that patch fails, now you will have a big problem. Sep 28, 2015 however, wrong grain direction makes book less usable and even leads to structural damage and early deterioration. In that article i laid out the process of how to make a counter form that will help keep the pieces level and allow linen reinforcement to dry slowly in. The second number in the papers dimension indicates the grain. It may be easier to start by placing the soundpost closer to the centre of the instrument, and then pulling it toward the fhole once it has been placed. A soundpost crack is tough to repair and results in. It often happens in the transition area from end grain to edge grain, where the wood gives. All gallery repairs for nicole alosinac luthiery guitar.