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bob ward
12-13-2010, 12:45 PM
Apologies for interrupting the board with my minor HSM triumph. There should be a wink right here but the software counts that as a photo.

I'm replacing the generator on my 53 Hudson with a modern alternator, so I needed to make an 84mm OD (3 1/4") B-section V belt pulley with 17mm bore. I thought I'd try the job using my 3.2mm carbide insert parting blade, because I've got one of them, rather than worry about form tools, and it all worked quite well. One reason it worked I guess is because I made an aluminium pulley, don't know that I would go too well with a steel or cast iron pulley.

First job was to make a nice stiff mandrel to stand the pulley blank an inch and a half or so off the chuck face. This was because I was going to be swiveling the compound round at 17 to cut the pulley sides and would need clearance on the LH side of the pulley.

http://i237.photobucket.com/albums/ff28/sirrobertthegood/IMG_0029-1.jpg
The mandrel is a piece of 2 1/4" round steel with the end turned down to 17mm, same as the new alternator. The aluminium blank is 84mm x 25mm and is clamped to the mandrel with a 30mm washer and M10 bolt.

http://i237.photobucket.com/albums/ff28/sirrobertthegood/IMG_0030-1.jpg
Put the parting off blade in to the depth of the V groove which is 18.2mm deep and also use the blade to mark the edges of the V groove which is 16.6mm wide

http://i237.photobucket.com/albums/ff28/sirrobertthegood/IMG_0034-2.jpg
Swing the compound to 17 and take off 1mm at a time until the groove is the right width. As you would expect there is a fair bit of deflection in a parting blade when its only cutting on one edge, quite a few spring cuts were needed before the blade stopped removing metal. At least the insert stayed in the holder, which was another unknown.

http://i237.photobucket.com/albums/ff28/sirrobertthegood/IMG_0035-3.jpg
All done and ready to go to work.

Evan
12-13-2010, 12:58 PM
I have made many a pulley in similar fashion. I use a stick of HSS and just grind a cutting tool with the correct angle on each side with a parting style edge on the front and zero top rake. It saves a lot of fiddling around with the compound.

Nice work, make sure the belt doesn't bottom in the pulley.

becksmachine
12-13-2010, 01:33 PM
Good job Bob!!

You probably would have had success also in both cast iron and steel with this method. You may have had even more deflection in steel, but you can alleviate that somewhat by leaving the parting tool square to the spindle center line instead of turning it to be parallel to the compound travel. You should be able to do this as long as the root width of the groove is wider than the parting blade.

One of the major advantages of this method is the lack of chatter, as there is much less cutting edge engaged as compared to using a form tool.

Dave

Black_Moons
12-13-2010, 02:50 PM
Nifty. I made a tool that might help with such tight grooves.

Its a forked devil toung tool! I'll get a picture if anyone wants.. But basicly, its the equvilent of a left AND right hand tool in one, with a recess in the center beween them, And a lot of side relief on both sides.

The usage is you plunge in slightly, Then move the tool sideways at least one width of the tool. Then your free to plunge in again, And move back.

Idea being it keeps the amount of tool in contact with the work to a minimal amount (Just the two tips) insted of the whole tool face, And allows you to do most of the removal work by moving side to side, Insted of plunging in.

I used this tool on the end of a boring bar to cut an ID groove and there was no chatter at all, And you can face both sides of a tapered groove with one tool without adjusting its angle, as well as turn the bottom smooth.

WaveDude
12-13-2010, 03:42 PM
Nifty. I made a tool that might help with such tight grooves.

Its a forked devil toung tool! I'll get a picture if anyone wants.

Pics please.

miker
12-13-2010, 06:15 PM
Black_moons, Yes pictures please!!!!

Rgds

Paul Alciatore
12-13-2010, 09:12 PM
Neat! Aint it wonderful being able to make exactly what you need?

Carld
12-13-2010, 09:25 PM
Long ago I ground a 1/4" sq HSS cutter with a profile much like the parting tool insert only more exaggerated. I used it to cut over size grooves and I did a pulley groove once with it. I kept it perpendicular to the axis of the lathe and it worked very well. I went into the shop to look it up and take a picture and can't find it. I must have ground it to a different shape but I still think it is out there somewhere. I just can't believe I reshaped it for something else.

I have used my insert parting tool like Bob did but I kept it perpendicular to the work and it did a fine job.

gwilson
12-13-2010, 09:26 PM
Like I said: A man who has a lathe and a mill doesn't have to put up with too much crap!!

Carld
12-13-2010, 09:35 PM
Yes, he can make his own crap :eek: I mean stuff.:D

Peter S
12-14-2010, 06:29 AM
I'm replacing the generator on my 53 Hudson

Bob,

One of my favourite cars, preferably a Hornet, but I once tried to buy a (yellow) '53 Super Wasp when I was younger, but couldn't quite afford it. The same car still turns up at events around Auckland...:)

snowman
12-14-2010, 08:02 AM
I have made many a pulley in similar fashion. I use a stick of HSS and just grind a cutting tool with the correct angle on each side with a parting style edge on the front and zero top rake. It saves a lot of fiddling around with the compound.

Nice work, make sure the belt doesn't bottom in the pulley.

Last time I did that I ended up with chatter marks. Now I've been using the compound.

Lew Hartswick
12-14-2010, 08:47 AM
Quote:
First job was to make a nice stiff mandrel to stand the pulley blank an inch and a half or so off the chuck face. This was because I was going to be swiveling the compound round at 17 to cut the pulley sides and would need clearance on the LH side of the pulley.
Endquote:

No. Just do half and turn the pulley around on the arbor. Keep it closer
to the chuck.
...lew...

S_J_H
12-14-2010, 09:04 AM
Nice work Bob!

I have made many pulleys and used a similar method as you describe.

I ground this HSS tool to help eliminate chatter when cutting V's and grooving.
It works very good.

http://i109.photobucket.com/albums/n48/S_J_H/Stevie187.jpg
http://i109.photobucket.com/albums/n48/S_J_H/Stevie186.jpg

Steve

Carld
12-14-2010, 09:35 AM
FOUND IT! but I see S_J_H posted his tool also. Here is the tool I made long ago.

http://i82.photobucket.com/albums/j276/yeathatshim/PC140003.jpg

I mostly used it for under cutting an area on a shaft but also used it for a pulley groove once. I couldn't believe I had discarded or reground it to another shape, I just don't do that and it's why I have a drawer full of all shapes of cutters.

duckman
12-14-2010, 09:38 AM
Nice job but I would have made the pulley a lot smaller alternators need to spin fast up to a max of 14,000 RPM or more. You are replacing a generator which doesn't need to spin as fast, just my $.001673 worth sometimes my opinion is not worth a lot. :D

Black_Moons
12-14-2010, 02:12 PM
:( Shoulda got off my ass and posted those pictures I guess. Mine look pertty much like the other two, Except on one I had much more rounded noses on it, for trying to get a decent finish on plastic.

One thing to note is you can only plunge in as deep as you made the side relief, However the side relief does not need to be an angle that continiously makes the tool narrower, It just needs to be a few mils ground away along the length.

A small round diamond file is great for makng the recess in the center. Maybe gouge it first with a dremel (Cutoff disk or tiny cylinder) so the file does not skate around.