- Katılım
- 20 Mar 2005
- Mesajlar
- 129
- Konu Yazar
- #1
Dragstar için rüzgarlık yapımına netten bişeyler buldum ama inch le falan anlatıyo.. sizin bildiğiniz bi site veya bilgi varsa lütfen yazın..
This Do It Yourself (DIY) method for cutting down a motorcycle windshield has been developed by R. Denny Blew, Co-Moderator of the Harley-Davidson Forum. At the end of this Step-by-Step, you'll find a link to a forum discussion about this procedure. If you have any questions or comments, please post them in the forum discussion.
Some windshields have limited height adjustments, and most don't have adjustments at all. So, if you need a shorter windshield, you can buy one that’s closer to what you need or simply cut down the one you have.
Cutting down a windshield is more scary than it is difficult. For the most part, all you need is a bit of courage and few items that you have lying around or can get access to. What I’ve written here is the full blown version. You might get away with skipping some steps or using some shortcuts but this method assures a job well done.
It takes almost as long to explain it as it does to do it because I spell out everything. Don't let the length discourage you. The whole job, once you have tools in place, can be done in less than an hour. Do a second one and it'll take thirty minutes. So here goes.
page 2
Stuff You'll Need
* A bandsaw: even a hobbyist model will do, or a quality jigsaw with a fine toothed blade installed. Procedures for both these techniques are the same except for the actual cutting process. I’ll explain later.
* Belt sander with a 180 or 220 (+/-) grit belt
* A construction level: 4 feet long is ideal but you might get away with a 3 footer on a small bike
* About 15' of 2" wide duct tape. Note: Some say duct tape can hurt a windshield's surface. If there's any concern, masking tape can be substituted for duct tape in the following steps.
* Few short pieces of low-stick (painter’s) tape
* Fine-line magic marker and / or awl
* Piece of cotton cloth about one square foot
* Two sheets of normal size printer or copier paper
* One sheet each of sandpaper in grits 80 / 120 / 180 / 240 / 400 (or a sequence similar to that)
* A helpful friend or two.
It should go without saying to take safety precautions. You could get something in your eyes, zip off a finger, breathe some fumes or whatnot. I’m no safety expert. I’m just telling you how I cut a windshield and recommend you don’t do something stupid.
That said, and with tools at hand, the toughest part of this whole procedure involves two decisions: where to make the highest center point of your arc, and how to shape the rest of the arc.
page 3
Establish the Highest Center Point
From a rider's standpoint, the highest cut point wants to be about an inch below eye-level with the bike laden with the rider’s weight. This allows an unimpeded sight line while dispelling 90% of the buffet and airborne solids over the rider’s head.
1. Have a buddy steady the bike, get the rider on and have them apply all their weight.
2. Have the rider look straight ahead.
3. Lay one end of the level along side the rider’s head at dead center eye level.
4. Place the opposite end against the inside of the windshield, get your bubble level and using your fine line marker, make a mark on the windshield. If it doesn’t mark well, use an awl and scratch a mark on it.
So now you have established a dead-on eye level at the windshield. But the ultimate mark we’ll need is going to be about an inch below this. (The rider can get off now). So ...
1. Drop down 1" and make a second mark. This second dot will serve as your ultimate highest center point.
2. Helpful Note: Go back and "X" out your original top dot: this will no longer be used.
3. Critical: It’s absolutely essential this second dot be dead center (from a left to right perspective) on your shield.
page 4
Shaping the Arc: Set Up a Template
This procedure requires a bit of artistic flair or perception to get the arc eye-pleasing. Obviously, one can't just cut, say, 3" off the thing all way round because that would narrow your shield. You need to gradually lessen the severity of the arc so by the time you approach the sides, you're removing less and less and ultimately none. The best advice I can give here is to make a template.
1. Tape two sheets of 8.5" x 11" paper end-to-end so you end up with a piece 8.5" by 22".
2. Start with covering the inward left quadrant of the shield. Lay the paper across it with the 22" dimension horizontal so that the top of the paper just clears the top edge of the shield and the balance covers the rest of the upper left quadrant.
3. Now spot tape it in place with painter’s tape it to keep it from shifting around (you’ll only keep it there a minute).
4. Mark on the paper where your highest point dot is. You should see it through the paper. If not, lift up the paper to find it.
5. Make a second mark at the point on the lefthand edge where you think the arc should taper off the shield (you'll make the actual arc later on).
6. Now, while holding the paper in place, go round to the front of the shield. Run your marker across the top edge of the shield, so you trace the paper at the top shield edge and around the side of the shield.
7. Remove (untape) the template.
page 5
Establishing the Arc on the Template
This is the artistic portion. Aside from employing complex oval-making tools, I recommend playing with this via freehand until you’re satisfied with the curve (arc).
1. Using scissors, cut the template where you made the long mark indicating the top edge of the shield. Discard the top cutoff.
2. Lay the remaining template out on a flat table.
3. Using light pencil strokes, create a new arc. It will travel from your highest point dot, to that side point you marked, getting ever less wide as it approaches the side.
4. Once you’re satisfied with the new arc, convert it to a single hard line.
5. Using scissors, cut this new arc line then discard the lower cutoff.
6. Your completed template should look like a long, thin, curved triangle.
page 6
Preparing to Cut: Shield Preparation
Lexan can shatter or get jagged edges when being cut. One way to beat that is to stabilize the edges. So, you want tape covering both the back and front of the shield in a zone at least 2" above and below your intended cut line.
1. Remove shield from the bike for this procedure.
2. Momentarily lay your template on the left inner side of the shield, lining it up with your top shield edge, your highest center point mark and the lower left side. Now you know where your cut will be.
3. Keeping a mental image of where the lines fall, remove the template. (Don’t throw out the template; you’ll use it again.)
4. Put tape on where you’ll make your cut. The tape can run straight in short or long pieces. You just don’t want any kinks, gaps or overlaps. Again, apply the duct tape in a zone at least 2" above and below your intended cut line.
5. Now, reverse the template and do the right inner side of the shield.
6. Finally, repeat these procedures on the outer (front) side of the shield, mimicking the same general locations.
7. Now GO to either Step 7, Jigsaw Method, or Step 8, Bandsaw Method, depending on which method you want to use to make the actual cut.
page 7
Cutting the Windshield - Jigsaw Method
Now that you have the duct tape on, you need to put the final mark on your shield. Working on the outer (front) side of the shield:
1. Lay your template in the correct place (left side) and trace your new line across the surface of the duct tape.
2. Flip the template and do the reverse (rightward) direction. Now you have a new arc line: one to cut.
Jigsaws don’t make good cuts unless their bases are dead against whatever they’re trying to cut. So with a jigsaw, you’ve got to make your cut from the front side of the shield.
1. Install a fine-toothed blade. This will do less jumping around, plus make for a smoother edge.
2. Lay the shield, front side up, on a flat surface with the top line to be cut hanging over the edge.
3. As much as possible have an extra hand or two to hold the shield steady and rigid.
4. Make your cut smooth and slow, following just barely to the out side (upper side) of the line.
Note: Do not remove the duct tape yet.
Skip to Step 9, below.
page 8
Cutting the Windshield - Bandsaw Method
Now that the duct tape is on, you need to put the final mark on your shield. Working on the inner side of the shield:
1. Lay your template in the correct place (left side) and trace your new line across the surface of the duct tape.
2. Flip the template and do the reverse (rightward) direction. Now you have a new arc line: one to cut.
To avoid scratching other parts of your Lexan shield as you feed it through the bandsaw, you want to line the bandsaw bed with a protective cloth. On a bandsaw there is the blade, surrounded on both sides by a bed over which the material travels. We are only concerned with that portion of the bed to the outer side of the blade.
1. Spread a cotton cloth over the outer top side of the bed up to within half an inch of the blade. Note: Do not go totally up to the blade, as the cloth could get caught in the blade and bind.
2. Smooth out the wrinkles.
3. Duct tape it down so it won’t move.
Make the cut in one swipe. That means not having to stop, turn it around and attack from the other direction.
1. Orient the lower end of the shield towards the outer bed.
2. With the front of the shield face down, begin your cut, following just barely to the out side (upper side) of the line.
Note: Tilt the shield as you pass it through the blade area so as to keep the spot that’s being cut as close down to the flat of the table as possible. If you do not do this, the blade will tend to bind as well as not follow your arc.
Note: Do not remove the duct tape yet.
page 9
Fine Tuning the Shape
A belt sander can make quick duty of cleaning up your lines and removing high spots. Grits between 180 and 220 seem to work best. Anything coarser and you can do damage real quick. With your duct tape still in place and traces of your line still available:
1. Mount the belt sander upside down in a vise.
2. Set the sander for a low speed, then turn it on.
3. Holding the shield upside down with your line side towards you, take out the little hills and valleys along the arc. Rock the shield left and right so as not to spend too much time in any one place (which would cut an area into a flat shape, which you don’t want).
4. Now, you can remove your duct tape.
page 10
Final Shaping & Smoothing of the Edge
Most shield edges are rounded over. This looks better, is safer (less sharp) to be around, plus it lessens the likelihood of the edge shattering or chipping (thus starting a crack). Rounding-over is best done with sandpapers and by hand. In this case, sandpaper slightly curved in the palm or finger joints can do a quicker and more natural rounding over than any machine.
Before you actually start sanding, take a look at the profile of the edge on the rest of the shield. That’ll give you an idea of what kind of shape you’re shooting for.
I like to make my initial swipes with a medium grade grit, something like a 120 or 180, just to get a feel for the texture of the Lexan and the "action" of the sandpaper against it. If I see I’m making quick progress, I’ll stick with it, then work my way up through the finer (higher) grits. But if I’m not making as much headway as I need, I’ll move back to a coarser grit till I get the "action" I want, then reverse again and work my way down through successive finer grits. Finally, the 400 grit makes the edge about as fine as it needs to be. If you’re anal about it, you can go up to a 1000 or 2000 grit. (Super fine grits can be found in automotive stores in the body work department).
Install the cut-down windshield and enjoy a new ability to see where you're going in all kinds of weather.
This Do It Yourself (DIY) method for cutting down a motorcycle windshield has been developed by R. Denny Blew, Co-Moderator of the Harley-Davidson Forum. At the end of this Step-by-Step, you'll find a link to a forum discussion about this procedure. If you have any questions or comments, please post them in the forum discussion.
Some windshields have limited height adjustments, and most don't have adjustments at all. So, if you need a shorter windshield, you can buy one that’s closer to what you need or simply cut down the one you have.
Cutting down a windshield is more scary than it is difficult. For the most part, all you need is a bit of courage and few items that you have lying around or can get access to. What I’ve written here is the full blown version. You might get away with skipping some steps or using some shortcuts but this method assures a job well done.
It takes almost as long to explain it as it does to do it because I spell out everything. Don't let the length discourage you. The whole job, once you have tools in place, can be done in less than an hour. Do a second one and it'll take thirty minutes. So here goes.
page 2
Stuff You'll Need
* A bandsaw: even a hobbyist model will do, or a quality jigsaw with a fine toothed blade installed. Procedures for both these techniques are the same except for the actual cutting process. I’ll explain later.
* Belt sander with a 180 or 220 (+/-) grit belt
* A construction level: 4 feet long is ideal but you might get away with a 3 footer on a small bike
* About 15' of 2" wide duct tape. Note: Some say duct tape can hurt a windshield's surface. If there's any concern, masking tape can be substituted for duct tape in the following steps.
* Few short pieces of low-stick (painter’s) tape
* Fine-line magic marker and / or awl
* Piece of cotton cloth about one square foot
* Two sheets of normal size printer or copier paper
* One sheet each of sandpaper in grits 80 / 120 / 180 / 240 / 400 (or a sequence similar to that)
* A helpful friend or two.
It should go without saying to take safety precautions. You could get something in your eyes, zip off a finger, breathe some fumes or whatnot. I’m no safety expert. I’m just telling you how I cut a windshield and recommend you don’t do something stupid.
That said, and with tools at hand, the toughest part of this whole procedure involves two decisions: where to make the highest center point of your arc, and how to shape the rest of the arc.
page 3
Establish the Highest Center Point
From a rider's standpoint, the highest cut point wants to be about an inch below eye-level with the bike laden with the rider’s weight. This allows an unimpeded sight line while dispelling 90% of the buffet and airborne solids over the rider’s head.
1. Have a buddy steady the bike, get the rider on and have them apply all their weight.
2. Have the rider look straight ahead.
3. Lay one end of the level along side the rider’s head at dead center eye level.
4. Place the opposite end against the inside of the windshield, get your bubble level and using your fine line marker, make a mark on the windshield. If it doesn’t mark well, use an awl and scratch a mark on it.
So now you have established a dead-on eye level at the windshield. But the ultimate mark we’ll need is going to be about an inch below this. (The rider can get off now). So ...
1. Drop down 1" and make a second mark. This second dot will serve as your ultimate highest center point.
2. Helpful Note: Go back and "X" out your original top dot: this will no longer be used.
3. Critical: It’s absolutely essential this second dot be dead center (from a left to right perspective) on your shield.
page 4
Shaping the Arc: Set Up a Template
This procedure requires a bit of artistic flair or perception to get the arc eye-pleasing. Obviously, one can't just cut, say, 3" off the thing all way round because that would narrow your shield. You need to gradually lessen the severity of the arc so by the time you approach the sides, you're removing less and less and ultimately none. The best advice I can give here is to make a template.
1. Tape two sheets of 8.5" x 11" paper end-to-end so you end up with a piece 8.5" by 22".
2. Start with covering the inward left quadrant of the shield. Lay the paper across it with the 22" dimension horizontal so that the top of the paper just clears the top edge of the shield and the balance covers the rest of the upper left quadrant.
3. Now spot tape it in place with painter’s tape it to keep it from shifting around (you’ll only keep it there a minute).
4. Mark on the paper where your highest point dot is. You should see it through the paper. If not, lift up the paper to find it.
5. Make a second mark at the point on the lefthand edge where you think the arc should taper off the shield (you'll make the actual arc later on).
6. Now, while holding the paper in place, go round to the front of the shield. Run your marker across the top edge of the shield, so you trace the paper at the top shield edge and around the side of the shield.
7. Remove (untape) the template.
page 5
Establishing the Arc on the Template
This is the artistic portion. Aside from employing complex oval-making tools, I recommend playing with this via freehand until you’re satisfied with the curve (arc).
1. Using scissors, cut the template where you made the long mark indicating the top edge of the shield. Discard the top cutoff.
2. Lay the remaining template out on a flat table.
3. Using light pencil strokes, create a new arc. It will travel from your highest point dot, to that side point you marked, getting ever less wide as it approaches the side.
4. Once you’re satisfied with the new arc, convert it to a single hard line.
5. Using scissors, cut this new arc line then discard the lower cutoff.
6. Your completed template should look like a long, thin, curved triangle.
page 6
Preparing to Cut: Shield Preparation
Lexan can shatter or get jagged edges when being cut. One way to beat that is to stabilize the edges. So, you want tape covering both the back and front of the shield in a zone at least 2" above and below your intended cut line.
1. Remove shield from the bike for this procedure.
2. Momentarily lay your template on the left inner side of the shield, lining it up with your top shield edge, your highest center point mark and the lower left side. Now you know where your cut will be.
3. Keeping a mental image of where the lines fall, remove the template. (Don’t throw out the template; you’ll use it again.)
4. Put tape on where you’ll make your cut. The tape can run straight in short or long pieces. You just don’t want any kinks, gaps or overlaps. Again, apply the duct tape in a zone at least 2" above and below your intended cut line.
5. Now, reverse the template and do the right inner side of the shield.
6. Finally, repeat these procedures on the outer (front) side of the shield, mimicking the same general locations.
7. Now GO to either Step 7, Jigsaw Method, or Step 8, Bandsaw Method, depending on which method you want to use to make the actual cut.
page 7
Cutting the Windshield - Jigsaw Method
Now that you have the duct tape on, you need to put the final mark on your shield. Working on the outer (front) side of the shield:
1. Lay your template in the correct place (left side) and trace your new line across the surface of the duct tape.
2. Flip the template and do the reverse (rightward) direction. Now you have a new arc line: one to cut.
Jigsaws don’t make good cuts unless their bases are dead against whatever they’re trying to cut. So with a jigsaw, you’ve got to make your cut from the front side of the shield.
1. Install a fine-toothed blade. This will do less jumping around, plus make for a smoother edge.
2. Lay the shield, front side up, on a flat surface with the top line to be cut hanging over the edge.
3. As much as possible have an extra hand or two to hold the shield steady and rigid.
4. Make your cut smooth and slow, following just barely to the out side (upper side) of the line.
Note: Do not remove the duct tape yet.
Skip to Step 9, below.
page 8
Cutting the Windshield - Bandsaw Method
Now that the duct tape is on, you need to put the final mark on your shield. Working on the inner side of the shield:
1. Lay your template in the correct place (left side) and trace your new line across the surface of the duct tape.
2. Flip the template and do the reverse (rightward) direction. Now you have a new arc line: one to cut.
To avoid scratching other parts of your Lexan shield as you feed it through the bandsaw, you want to line the bandsaw bed with a protective cloth. On a bandsaw there is the blade, surrounded on both sides by a bed over which the material travels. We are only concerned with that portion of the bed to the outer side of the blade.
1. Spread a cotton cloth over the outer top side of the bed up to within half an inch of the blade. Note: Do not go totally up to the blade, as the cloth could get caught in the blade and bind.
2. Smooth out the wrinkles.
3. Duct tape it down so it won’t move.
Make the cut in one swipe. That means not having to stop, turn it around and attack from the other direction.
1. Orient the lower end of the shield towards the outer bed.
2. With the front of the shield face down, begin your cut, following just barely to the out side (upper side) of the line.
Note: Tilt the shield as you pass it through the blade area so as to keep the spot that’s being cut as close down to the flat of the table as possible. If you do not do this, the blade will tend to bind as well as not follow your arc.
Note: Do not remove the duct tape yet.
page 9
Fine Tuning the Shape
A belt sander can make quick duty of cleaning up your lines and removing high spots. Grits between 180 and 220 seem to work best. Anything coarser and you can do damage real quick. With your duct tape still in place and traces of your line still available:
1. Mount the belt sander upside down in a vise.
2. Set the sander for a low speed, then turn it on.
3. Holding the shield upside down with your line side towards you, take out the little hills and valleys along the arc. Rock the shield left and right so as not to spend too much time in any one place (which would cut an area into a flat shape, which you don’t want).
4. Now, you can remove your duct tape.
page 10
Final Shaping & Smoothing of the Edge
Most shield edges are rounded over. This looks better, is safer (less sharp) to be around, plus it lessens the likelihood of the edge shattering or chipping (thus starting a crack). Rounding-over is best done with sandpapers and by hand. In this case, sandpaper slightly curved in the palm or finger joints can do a quicker and more natural rounding over than any machine.
Before you actually start sanding, take a look at the profile of the edge on the rest of the shield. That’ll give you an idea of what kind of shape you’re shooting for.
I like to make my initial swipes with a medium grade grit, something like a 120 or 180, just to get a feel for the texture of the Lexan and the "action" of the sandpaper against it. If I see I’m making quick progress, I’ll stick with it, then work my way up through the finer (higher) grits. But if I’m not making as much headway as I need, I’ll move back to a coarser grit till I get the "action" I want, then reverse again and work my way down through successive finer grits. Finally, the 400 grit makes the edge about as fine as it needs to be. If you’re anal about it, you can go up to a 1000 or 2000 grit. (Super fine grits can be found in automotive stores in the body work department).
Install the cut-down windshield and enjoy a new ability to see where you're going in all kinds of weather.
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