# Difficulty While Making A Pulley



## prasad (Jul 1, 2015)

Guys, 

I was making a pulley out of aluminum stock. The pulley needs a round groove 5mm wide and 2.5mm deep with diameter at the bottom of the groove at 17 mm.  I ground the round profile on a HSS tool bit. Cutting was not easy. I was getting very loud growling sound and heavy vibration. I tried many changes such as varying tool bit height, increase front clearance angle & side clearance angle, back rake and of course feed rate. Nothing resolved the problem. Finally I had to plunge the tool at extreme slow rate at all settings. I also used WD40. I am attaching photos of the tool tip I made. 

Where did I go wrong? 
What is the better/right way to do it? 

Thanks
Prasad
Wynnewood PA


----------



## Micke S (Jul 1, 2015)

If you are attempting to turn the complete groove in one step I think it will cause this type of problem.


----------



## Flammable_Solid (Jul 1, 2015)

I think you are doing this on your 9x20 lathe, correct?  That is a big cut do do in a single pass.

Rough it out and only cut one side of the belt radius at a time.


----------



## RJSakowski (Jul 1, 2015)

As Micke S stated, generally, trying to cut with a broad surface causes chatter.  Try making a narrow tool to rough out most of the material and finish with your form tool.  You can either calculate the tool path or make a template to get you close.  If you go the calculation route, set your compound up parallel to the ways and use the compound and cross feed for your z and x position.


----------



## Bill C. (Jul 1, 2015)

You didn't say how you are holding the workpiece.  IF I was making it I would face both ends then drill and bore out the ID.  I would use the tailstock with a ball bearing center to hold the piece steady.  Like the others said rough out the groove(s) then finish the bottom with a form shaped bit.  If the finish cuts are not blending in use a smooth flat file to remove any lines.

Good luck, please post a finished photo


----------



## kd4gij (Jul 1, 2015)

Take somthing like a parting tool and rough it out in steps and then go in with the form tool..


----------



## prasad (Jul 1, 2015)

Thanks everyone. Yes, I am using my 9x20 Grizzly lathe. The work piece is held in a 6" 4-jaw chuck. Work piece is a 1.25" aluminum rod and it is initially turned down to 22mm OD and then I cut the pulley groove. I have 1" aluminum rod on order at McMaster.com which may arrive in a day or two. I will grind another tool bit to a narrower size and cut one side at a time. I do not want to use parting tool suggested by Martin. I always had same or similar problems with it. I will post picture once I have it finished. 

Thanks
Prasad


----------



## kd4gij (Jul 1, 2015)

A threading tool would work great for roughing it out.


----------



## prasad (Jul 8, 2015)

Guys, 

I finally made the pulleys to an acceptable level of finish. Pictures are attached. I used all the suggestions given by all. Main change I made was to thin the groove profile tool down to 3 mm wide from the previous 5 mm width. I want to thank everyone of you for your advice.

Thanks again
Prasad
Wynnewood PA


----------



## turnitupper (Jul 9, 2015)

Could you use a 5mm bullnosed end mill and something like this?
John.


----------



## prasad (Jul 9, 2015)

I dont get it. Can you please explain how to cut it? The pulley material is held in the lathe chuck. Where do I mount the end mill? Lathe tool post? Would it be rotating or just held in the tool post? I dont have bull nosed end mill but I can get one if the idea will work. 

Thanks
Prasad


----------



## Round in circles (Jul 9, 2015)

turnitupper said:


> Could you use a 5mm bullnosed end mill and something like this?
> John.




 I like that idea John,
 Is that a boring bar holder that's been given a  sleeved shaft with the chuck at one end and run off a power drill or a separate motor just below the base of the picture in the middle of it ?


----------



## prasad (Jul 9, 2015)

prasad said:


> I dont get it. Can you please explain how to cut it? The pulley material is held in the lathe chuck. Where do I mount the end mill? Lathe tool post? Would it be rotating or just held in the tool post? I dont have bull nosed end mill but I can get one if the idea will work.
> 
> Thanks
> Prasad


OK, I found the attachment that I had missed when I read your reply. Thats. I will try that next. I do have a Dremel attachment for the lathe. I will have to find a 5 mm round nose tool for Dremel if there is one. 

Thanks
Prasad


----------



## turnitupper (Jul 10, 2015)

Round in circles said:


> I like that idea John,
> Is that a boring bar holder that's been given a  sleeved shaft with the chuck at one end and run off a power drill or a separate motor just below the base of the picture in the middle of it ?


That's about it. Power drill, corded or cordless. Not mine, got image off 'net. I think someone here has made something similar but I cannot find it.
John.


----------



## turnitupper (Jul 10, 2015)

prasad said:


> OK, I found the attachment that I had missed when I read your reply. Thats. I will try that next. I do have a Dremel attachment for the lathe. I will have to find a 5 mm round nose tool for Dremel if there is one.
> 
> Thanks
> Prasad


Prasad
If you can't find a bullnosed end mill to fit your Dremel, you could try a 5mm round carbide burr with a 3mm shank. The good thing about these tools is that you don't have to be on center with them. You can cut from the top, bottom or anywhere in between.
John.


----------



## samthedog (Jul 12, 2015)

turnitupper said:


> Could you use a 5mm bullnosed end mill and something like this?
> John.



I don't know how important that particular profile is for the pulley but I probably would have done this in the dividing head with the mill. You would have no chatter, would not need to grind a special form tool and would have saved some time with head scratching. Failing that, you can make yourself a spring type tool holder like seen here:

http://www.ctemag.com/aa_pages/2012/120614-ShopOps.html

These were regularly used with form tools to prevent chatter and work an absolute treat. They are quite easy to make and are a godsend when making pulleys or convex / concave profiles that require large contact surfaces with the cutting tool.

Paul.


----------



## aametalmaster (Jul 12, 2015)

Don't plunge cut it. Just rough it to the depth you want with a pointed cutter. Then set your compound say 15 degrees and use a pointed sharp cutter and turn your toolpost to just cut with the tip of the cutter to the depth and width you want. I have done 100's this way. Then swing your compound 15 degrees to the other side and do that side the same way...Bob


----------



## Tozguy (Jul 22, 2015)

For aluminum you might consider more top rake on the tool. Neutral rake has a tendency to tear instead of slice such soft metal. Also, edge must be very sharp. A honed edge would give best results.


----------



## unioncreek (Jul 22, 2015)

When I made some pulleys out of aluminum I used a parting tool to rough cut the depth and with at the bottom of the pulley.   Then is set the compound at 30* and cut the left side with a facing tool and then turned the compound the other way to 30* and cut with a left hand facing tool.  

Bob


----------



## bfd (Oct 18, 2016)

I don't know how slow your lathe goes but slow it down, a full size cut can be performed if you go slow enough. also once the chatter starts its difficult to remove. Ive had to turn the lathe by hand to get rid of the chatter, lots of oil.  bill


----------

