In this instructable, I will go through the fabrication of frame sliders for a motorcycle. I have chosen, as an example, a Ducati Panigale.
In the event of a crash, frame sliders help to protect your bike against excessive damage. They space the body off of the pavement, thereby protecting portions of the bike from harm. We will fabricate these out of Delrin, a Polyoxymethylene plastic that takes abrasion very well. You may use any similar material.
- Bridgeport, Jet, or comparable metal lathe
- Fine grit sandpaper
- Duct tape
- Ducati Panigale
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Step 1: Measure and Plan
Use a ruler to determine how far your wheel sliders will have to protrude in order to protect your bodywork. This can be eyeballed and erring on the longer side is usually a safe bet. Also measure the inner diameter of the axle.
This is very important. You'll want to use some calipers to get as exact a measurement as you can to ensure a good fit.
You'll want to have an inner sleeve that goes into the axle about an inch or so to give the sliders some structural rigidity. Factor that into your cutting plan.
Step 2: Mount Your Material
Once you have your measurements all squared away, grab your materials. Delrin is a good choice because it's quite strong and machines very nicely. Here, we have 2-inch stock.
Use some duct tape to protect the base of your work and to provide some grip on the slick surface.
Go ahead and chuck up your piece in a 3 or 4 jaw chuck.
Make sure that you have enough material to work with. For instance, if the overall length of your finished piece will be 3 inches, make sure the piece you use is at least 5 or 6 inches to allow for waste material to fit within the chuck.
Step 3: Center Drill
You will need to drill a hole clear through your piece for the mounting bolt. I chose an M8 bolt, so we need to drill out a clearance hole for that.
First, grab your center drill, chuck it up, and put a nice center-hole in your piece. Make sure this is good and centered and that your work is securely chucked. If you are having problems with your piece slipping into the chuck, check out this instructable.
Set your speed to something moderate, about 600rpm should be fine, and punch your center-hole.
Step 4: Drill
Grab a drill bit of the appropriate size to give your bolt clearance. If you are unsure, check a clearance chart. Make sure that you find a bolt that is large enough to hold your pieces in place when you bolt them to your bike.
You can keep the lathe speed pretty high, 600 rpm is probably fine. This material is soft enough to get away with that, but for large bits drilling into metal, you'll want to slow down.
Drill clear through your piece, or as deep as your piece will be long (if your final piece is 3 inches long, drill 3.25 inches in to be sure that your hole clears).
Step 5: Fillet/Chamfer
Slow your lathe down to about 60-100rpm and grab your trusty file.
CAREFULLY straddle the chuck with your arms and slowly move your file back and forth over the corner of your piece (I am only using one hand in the picture but that's because I had to take the picture; you should use two hands).
Chamfer or fillet your piece to the desired specification.
Step 6: Grab Your Parting Tool
Go ahead and chuck up a nice sharp parting tool. Make sure you chuck it up perpendicular to your piece and be sure that the cutting head is level (or just below) the center line of your piece.
Step 7: Touch-off Your Parting Tool to Establish Reference
Turn the lathe on at a low rpm and bring your parting tool to the very edge of your piece until it juuuuuust touches...
When you see a little bit of material come off, stop moving and zero your dial. This is your reference point for your measurements.
Step 8: Move to Your First Cut
Move your parting tool along your piece to the specified distance.
Don't forget to account for the width of the parting tool!
Step 9: Make Your First Cut
Move your parting tool inward to the specified distance.
TIP: Don't go all the way to your measured size. Leave it a little bit large. We will use sandpaper to take off the last few thousandths and ensure a nice slip fit. For example: if your spec diameter is 1.68in, cut your collar to be 1.69in.
Make your first cut, then move over the with of the tool and make another cut. Do this a couple of times until you have cut out a large area.
Step 10: Switch to Your Facing Tool
Go ahead and switch to a facing tool. Since you cut out a wide shoulder in the previous step, you should be able to fit a facing tool in there without running into the shoulder on the right hand side. Face down the rest of the collar to the specified thickness (or just larger than).
Step 11: Counterbore
Grab an endmill that is larger than the head of your chosen bolt. Chuck this up in the tailstock and counterbore the end.
CAREFUL: Make sure that you don't bore too deep. Use the shoulder you just created to measure from and make sure that your counterbore doesn't come close to it. you want to leave enough meat to maximize strength.
For example: If your shoulder (the part that has a smaller diameter and slips into the axle) is 1in from your reference point, your counterbore should only go in a half inch or so.
Step 12: Part Your Piece Off
Go ahead and move your parting tool to the final dimension and part your piece off.
Step 13: Cleanup!
Make sure you clean up your mess :]
Step 14: Bolt on and Marvel at Your Awesomeness :]
Grab some light sandpaper and slowly sand down the collars on your pieces until they just slide into the axle. This slip-fit will add structural stability and keep your sliders nice and snug.
Find two bolts that will fit inside the holes you drilled earlier and use a standoff to span the gap. Bolt your pieces on nice and tight and use some loctite to make sure they don't work themselves loose.
Now when you eat pavement, you'll do it in style.
And hopefully not totally wreck your paintjob...