Tool bit for V-Belt Pulley
 

A Few Questions:

I recently made a V-belt pulley but
with some difficulty because I had
trouble setting up a 20 degree angle
on the inside surface closest the
lathe head. I suppose I could turn
the pulley around but then it might
not run true.

Anyway, seems like I should be able
buy an off-the-shelf tool bit with
a snubbed 40 degree included angle.
Just plunge a certain depth and I'm
done. Is there such an animal?

Second, I could go for a smaller
belt but can't seem to find anything
smaller than 2L. Where should I look?
And if I can't go smaller, how come?

Brad Smallridge
AiVision

Tool bit for V-Belt Pulley
 

Anyway, seems like I should be able
buy an off-the-shelf tool bit with
a snubbed 40 degree included angle.
Just plunge a certain depth and I'm
done. Is there such an animal?

I tried that. Even on my 10EE it was a chatter box. Just too much cutting
surface area. I made a 40 degree point HSS form tool. Ruff out pulley with
cutoff blade, cut left side, move carriage, cut right side. This was for a
six groove sheave and it only took and hour.

Karl

Tool bit for V-Belt Pulley
 

On Fri, 9 Nov 2007 09:42:55 -0800, "Brad Smallridge"
wrote:


Second, I could go for a smaller
belt but can't seem to find anything
smaller than 2L. Where should I look?
And if I can't go smaller, how come?

Metric v-belts as small as 5mm wide are available, though not widely.

If you need a reinforced belt, look at poly-vee belts...
http://fp.transdev.plus.com/pages/be...polyv_main.htm

For very light duty, an unreinforced round urethane belt may work for
you, for example:
http://www.pyramidbelts.com/rbelts.php
http://www.shinglebelting.com/extrusion.html

--
Ned Simmons

Tool bit for V-Belt Pulley
 

Brad,
First, be certain of your dimensions, please reference the machinery
handbook. In that you will find that the "V" angles are slightly different
for each belt size. They may look the same, but they are not. Second, yes,
you can plunge cut the groove in a single operation, but the blank must be
really securely chucked and supported with the tailstock, the machine should
be at least 8 tons in mass and have a 10-15 hp motor. You need a seriously
stout machine to cut an "A" size pulley. Without that the chatter will make
the task impossible. I have a 18 x 54 Lodge & Shipley in pristine condition.
It weighs 6 tons, has a 15 hp motor and I don't do it. When making one off
pulleys, I use a parting tool and blow the center out to depth, then I use a
specially ground tool to shape the sides, but I only do that on the L & S.
On smaller machines, the first step is the same then I turn the compound to
the correct angle and machine each side seperately.
Steve

"Brad Smallridge" wrote in message
...
A Few Questions:

I recently made a V-belt pulley but
with some difficulty because I had
trouble setting up a 20 degree angle
on the inside surface closest the
lathe head. I suppose I could turn
the pulley around but then it might
not run true.

Anyway, seems like I should be able
buy an off-the-shelf tool bit with
a snubbed 40 degree included angle.
Just plunge a certain depth and I'm
done. Is there such an animal?

Second, I could go for a smaller
belt but can't seem to find anything
smaller than 2L. Where should I look?
And if I can't go smaller, how come?

Brad Smallridge
AiVision

Tool bit for V-Belt Pulley
 

I ground a narrow bit to approximately the correct angle on both sides
(like an Acme threading tool) and rough out the groove by wiggling it
from side to side while slowly advancing. The angled sides are short
and not ground to cut well, so they serve as stops. The chip is small
enough that a large spoked pulley pressed onto a mandrel doesn't slip.
Then I finish the sides to the proper angles with the compound.
Jim Wilkins

Tool bit for V-Belt Pulley
 

On Fri, 9 Nov 2007 12:01:17 -0600, "Karl Townsend"
wrote:

Anyway, seems like I should be able
buy an off-the-shelf tool bit with
a snubbed 40 degree included angle.
Just plunge a certain depth and I'm
done. Is there such an animal?

I tried that. Even on my 10EE it was a chatter box. Just too much cutting
surface area. I made a 40 degree point HSS form tool. Ruff out pulley with
cutoff blade, cut left side, move carriage, cut right side. This was for a
six groove sheave and it only took and hour.

Karl




Ditto. The tool I use is made from O1 and has a 40 degree end and a 30 degree
end. Small diameter pulleys need significantly less than 40 degrees due to
distortion of the belt section. Once most of the meat is removed with a
parting tool, the flanks can be cut one at a time quite smoothly.

The other thing to do is to put the pulley blank on an arbour between centres.
That way it can be attacked with more clearance at the headstock end if the
topslide is cranked over.


Mark Rand
RTFM

Tool bit for V-Belt Pulley
 

"Brad Smallridge" wrote:

I recently made a V-belt pulley but
with some difficulty because I had
trouble setting up a 20 degree angle
on the inside surface closest the
lathe head. I suppose I could turn
the pulley around but then it might
not run true.

If you had turned the pulley on a mandrel between centers for left side
clearance for the compound, life might have been easier. We turn a lot of V
belt pulleys for class 8 trucks using a carbide parting tool but that is on
a cnc lathe where things are a bit different than an engine lathe using a
compound.

Wes

Tool bit for V-Belt Pulley
 

I just grind mine from large HSS bits, like 5/8" , and use an existing
pulley as a gage. I've turned cast iron, steel, and aluminum pulleys no
troubles on my 16" Southbend, with an aloris toolpost. Use a parting tool to
hog out the middle first. If you do get chatter marks, just consider that
extra grip for the belt :^)

Tony


"Brad Smallridge" wrote in message
...
A Few Questions:

I recently made a V-belt pulley but
with some difficulty because I had
trouble setting up a 20 degree angle
on the inside surface closest the
lathe head. I suppose I could turn
the pulley around but then it might
not run true.

Anyway, seems like I should be able
buy an off-the-shelf tool bit with
a snubbed 40 degree included angle.
Just plunge a certain depth and I'm
done. Is there such an animal?

Second, I could go for a smaller
belt but can't seem to find anything
smaller than 2L. Where should I look?
And if I can't go smaller, how come?

Brad Smallridge
AiVision

Tool bit for V-Belt Pulley
 

Brad Smallridge wrote:

A Few Questions:

I recently made a V-belt pulley but with some difficulty because I had
trouble setting up a 20 degree angle on the inside surface closest the lathe
head. I suppose I could turn the pulley around but then it might not run
true.

Anyway, seems like I should be able buy an off-the-shelf tool bit with a
snubbed 40 degree included angle. Just plunge a certain depth and I'm done.
Is there such an animal?

Second, I could go for a smaller belt but can't seem to find anything smaller
than 2L. Where should I look? And if I can't go smaller, how come?

You didn't say what material you used. When I made a 4-step sheave I started
by drilling/reaming the hole, then I used a mandrel and did every other
operation on the one setup. I remember grinding a tool with a long angled
tip but I'm positive I used the swiveled compound to feed it along the edge
rather than plunging it all at once - this on a 9" South Bend, not a rigid
lathe. Of course, rough out the slots with a parting tool, get most of the
material out of there. I made mine out of aluminum - it's held up fine for
about seven years now, no signs of slackening. I've seen guys glue up circles
of hardwood and turn those into sheaves too. Steel would be real hard on a
little lathe.

Grant