How do i go about turning a crown on a idler wheel.

Gallery, Projects and General > How do I??

<< < (3/4) > >>

Jasonb:
When I do it on flywheels and pullies I roughly divide the pully face by 5. The middle 1/5th does not get touched, the 1/5th either side of that get a 1deg taper and the outer 1/5ths get a 2 degree taper put on with the topslide. Then just blend wth file, hand scraper or flapwheel.

J

andyf:
If there was an easy way of rotating the pulley while cutting it, you could mount it transversely on a mandrel on the cross-slide and use a boring head in the spindle (or a cutter mounted off-centre on the faceplate) to create the crown.

But the easiest way might be to cut tapers from each side, starting with (say) a pair of 0.5o ones, leaving a flat strip down the middle a few mms wide, and then two more at 1o, then 1.5o and finally 2o. Then take a file to it to turn the series of tapers into a smooth crown.

Andy

NeoTech:
Jasonb, Andyf

This is what i thought myself at first aswell, but it seemed it would be "edges" but i guess they can be easily sanded down?
But seems its the valid way of doing it, cause i have not material to produce a radii tool, or can do that nify thing with my compound (explored that option yesterday).

andyf:
OK, here's another way. File a bit of scrap sheet to the profile you want and mount it horizontally on the bench behind the lathe as a template. Have a length of rod sticking out from the back of the cross slide so it contacts the template. The rod should be in line with the tip of your turning tool.

Set the pulley in the chuck, such that the tool is touching it half-way along and the rod is in contact with the middle of the template. Then, cutting away from the chuck and using the cross-slide handle to keep the rod in contact with the template, form one half of the crown. Reverse the pulley in the chuck and do the other half, and if necessary use a file to get rid of any tiny ridge left due to slight lack of concentricity between each operation.

Come to think of it, you only really need half of the curve on your template, but it would probably be easier to judge the shape while filing it up if it was full-length.

Andy

75Plus:
I don't understand why this project is such a problem. Had the question been "How do I replicate a Morse or Jacobs taper" half the members on this board would have explained how to do so by off setting the top slide the proper amount and, using the top slide feed, produce the required angle.

Call it a "Crown" and it's a new game. Why, the principles are the same. There is nothing that says the crown must, or should be, a radius. Identical tapers on each side of the wheel center is all that is required. If desired, the tapers can be blended into the center with a bit of emery cloth.

Navigation

 Message Index

Go to full version