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  #1  
Old 12-11-2018, 11:59 AM
Mac_Makes Mac_Makes is offline
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Default Rolling Cones, without a roller?

Sorry if this has been done to death. New to the trade and my search terms aren't finding much.

I want to make steel motorcycle fork covers and coned exhaust mufflers. How do you A) roll a cone this small on a standard size set of rollers B)Roll a cone with... say a bit of round stock/pipe?

Thank in advance for any links/explanations.

Mac
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Old 12-11-2018, 12:06 PM
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Jacob Jacob is offline
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You could try bolting a piece of pipe to your bench top with a spacer with just enough clearance for the metal to slide between the two.
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Old 12-11-2018, 01:54 PM
skintkarter skintkarter is offline
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Mac, I bought a small bench roller (circa 1" diameter x 12" long rolls) which I've been able to abuse for all sorts of small jobs. Depends on how big your small end of the cone is. I think that with a 1" diameter roll, you can get down to about 1.5" when you allow for springback. But you may not get enough tilt on the forming roll for a steep cone. Ideal for gentle cones and your tubular bits, but beware of the ends which will either need a pre-bend or some tapping up to after forming to deal with the flats.

The other option that I'd look at (as I have a lathe) is making a tapered mandrel welded to some square stock or flat bar that I could grab in a vice, and then use a slapper to coax the blank around the former. Again you would need the former to be smaller (think long bench stake) to allow for springback. If the former were long enough, you could perhaps form the cone towards the end, tack up and then use the larger end as an anvil to flatten your tacks on and then a final planish on.

Post some pics of what you are trying to achieve - lots of far more experienced shapers on here than I who have probably been through what you are contemplating.
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Old 12-11-2018, 04:31 PM
Mac_Makes Mac_Makes is offline
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Thanks Guys.
SkintKarter I'm definitely going to mess around with mandrels next free day I have (2036 at current projections). I have a nicely kitted out machine shop at my disposal but zero sheet working tooling. 1" slip rolls would be perfect... definitely going for an ebay cruise!
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Old 12-11-2018, 06:01 PM
6randy 6randy is offline
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Default Making cones

Check out blacksmith supply business they have cone mandrel in many different sizes and shapes
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Old 12-12-2018, 03:21 PM
fciron fciron is offline
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The forming of the cone is relatively simple, it's a good pattern that makes all the difference. Jacob's suggestion of a piece of pipe bolted to the bench with a couple of washers as spacers is good. Remember that the bends are not parallel but diverge slightly so that they are further apart at wide end of the cone.

A cone shaped mandrel for refining the cone is helpful, it does not need to be a perfect match to the cone you're making.

Here is a link to make the pattern, they're working with plastic, but they principle is the same.
http://polyfab.biz/plastic-cones-fabricate.php
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  #7  
Old 12-12-2018, 03:34 PM
Terry Stolarski Terry Stolarski is offline
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I don't do very much metal shaping anymore now that I am retired but I do check in once in while to see what you people are up to. I checked in last night and seen this post and I hade to make a couple of sets of these tapered fork covers today so I took some photo's. The form or mandrel that I use for making these is pretty elaborate because these have to have two flats on each side. However, I have made these using a piece of Oak for small runs. If you notice the mandrel that I am forming these over have about 3/4 of an inch on the bottom that sticks out which is a must have because when the metal is formed around it, it is like a morris taper and you cannot get it off the form if you do not have something to pound against. Because I have 2 flats on my piece of metal I bend two 40 degree bends on each side of it. I crudely bend that by hand around my mandrel and line up the weld seam. I leave that weld seam tipped up a little bit because it makes it way easier to metal finish. Now I metal finish it then I start sliding it up the mandrel and work it with a leather faced slapper and start hammering in the flats then when I get it to slide all the way up the mandrel I take a flat piece of steel and finish the flats. My mandrel also has a hammer form on the top because the piece that goes on the inside on the top has a quarter inch lip that goes on the inside. When I make the round circle for the top I always start out with a square piece of metal and "x" it that gives me a square line to get all my holes correct. When Harley made these they have two 8-32 screws that hold them to the top of the fork. These are made out of 20 gauge so they bend real easy on the screws and are very easy to get out of alignment and they hit on the forks. So what I do is I weld a piece of tubing inside the center hole on top that fits over the fork tube and goes down about 1 1/4 inches and keeps these in alignment. I hope this helps. (see photo's)
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Old 12-12-2018, 03:40 PM
Mac_Makes Mac_Makes is offline
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Wow Thank you very much Terry thats exactly what T was after! I'm going to have to read your post a few times to get it in my head. Unfortunately I cant see photos yet. I'd love to be able to make these without a roller, just another trick to add to the arsenal eh.
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Old 12-12-2018, 03:47 PM
Terry Stolarski Terry Stolarski is offline
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PC120002.jpg

PC120003.jpg

PC120007.jpg

PC120012.jpg

PC120013.jpg

PC120014.jpg

PC120015.jpg

PC120016.jpg

PC090003.jpg

PC090006 (1).jpgphoto's Harley cowbells/dust covers

PC120002.jpg

PC120003.jpg

PC120007.jpg

PC120012.jpg

PC120013.jpg

PC120014.jpg

PC120015.jpg

PC120016.jpg

PC090003.jpg

PC090006 (1).jpg

Last edited by Steve Hamilton; 12-12-2018 at 04:50 PM.
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Old 12-12-2018, 03:51 PM
Terry Stolarski Terry Stolarski is offline
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more pics of Harley cow bells/dust covers

PC090005 (1).jpg

PC090007.jpg

PC100009.jpg

Last edited by galooph; 12-12-2018 at 04:43 PM.
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