First time on a lathe.....

ken6881 · Feb 26, 2016

So I am needing to do some machine work on my f450 build. Literally first time on a lathe so don't mock to hard

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Working on cutting serpentine. Belt grooves for my dt360 balancer. Obviously not wanting to jack up a balancer I picked up some scrap round stock and went to work. Any suggestions tools I need .... Our machine shop is pretty sad when it comes to tool selection we have all the big stuff but none of the little pieces to go with it.

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ja_cain · Feb 26, 2016

ken6881 said:
So I am needing to do some machine work on my f450 build. Literally first time on a lathe so don't mock to hard
View attachment 42336

Working on cutting serpentine. Belt grooves for my dt360 balancer. Obviously not wanting to jack up a balancer I picked up some scrap round stock and went to work. Any suggestions tools I need .... Our machine shop is pretty sad when it comes to tool selection we have all the big stuff but none of the little pieces to go with it.

Need a pic of the piece chucked up and the tool that you were using. Looks like you are having rigidity issues. I would look for a cad drawing of a serpentine pulley so you can see what the radius of the tip of the cutter should be. I would assume you also need to know how deep to make it and the angle of the groove walls so they interface with the belt grooves correctly.

I'll try to find something for you and post it up. These details should be standard.

ken6881 · Feb 26, 2016

I was going to take a pulley with me to the local supplier and see what I could find that fits. It looks like rigidity issues to me as well by the "feel" and marks in the grooves I cut.

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ja_cain · Feb 26, 2016

I think this is what you need. Just need to find out which letter the belt is you are using.

Baker42 · Feb 26, 2016

Dial indicator, depth gauge, a magnetic base, and patience. I was a CNC machinist by trade until I got layed off in 06. Got into the plumbing/mechanical trade and never looked back. I still play around on a colchester lathe and a bridgeport mill making junk for my bronco. Patience and math is key. Good luck

ken6881 · Feb 26, 2016

I was trying to figure out how to do the spacing between grooves but the dial indicator on a magnetic base is the way to go for good measurement. Thanks baker and ja_cain

PsdPullerJr · Feb 27, 2016

Make sure your tool is on center to the work piece and your using the correct rpm for the diameter your cutting.

gwunter · Feb 27, 2016

Get a piece off HSS and custom grind it if need be.....on a surface grinder if you can. But you might be able to find a cutter with the proper tip angle on it. If I was you...I would lock the saddle down, turn the cross slide 90*(indicated in) and zero out your compound on the first groove, then use cross slide to feed cutter into work, once to depth back out cross slide and move cutter via compound to the next groove. Continue till all groves are done. Be careful of your surface speed as psdpuller said. Orrrrr

If your mill is outfitted with a rotary table you could once again find/make the right cutter and then use the z axis to get your groove spacing and your x axis for your groove depth. Easy peazy once set up.

mandkole · Feb 28, 2016

Youre going to be needing groove detail for the 'K' cross section belt.

All very good suggestions above. Having been in the belt business for years now, the groove profile and spacing of a serpentine style belt is critical for good belt performance. Groove center is critical-- you are allowed 1/2 degree offset for every foot of belt span. Runout will make belt tension management go crazy. With anything incorrect, you will kill belts or have squawking belts very quickly. Normally all of the grooves are cut at the same time with specific tooling, but very skilled guys with nice machines can do it one at a time.

Id like to play with a lathe some day but accessory drive pulleys are not something that I'd be tackling as my first project--although not cheap, there are lots of companies that can do this.

good luck!

ja_cain · Feb 28, 2016

mandkole said:
Youre going to be needing groove detail for the 'K' cross section belt.

All very good suggestions above. Having been in the belt business for years now, the groove profile and spacing of a serpentine style belt is critical for good belt performance. Groove center is critical-- you are allowed 1/2 degree offset for every foot of belt span. Runout will make belt tension management go crazy. With anything incorrect, you will kill belts or have squawking belts very quickly. Normally all of the grooves are cut at the same time with specific tooling, but very skilled guys with nice machines can do it one at a time.

Id like to play with a lathe some day but accessory drive pulleys are not something that I'd be tackling as my first project--although not cheap, there are lots of companies that can do this.

good luck!

Good info! It would be cool if we could locate the specific tool that you would use to cut the grooves for a k type belt. I'll do some digging around and see what I come up with.

ja_cain · Feb 28, 2016

gwunter said:
Get a piece off HSS and custom grind it if need be.....on a surface grinder if you can. But you might be able to find a cutter with the proper tip angle on it. If I was you...I would lock the saddle down, turn the cross slide 90*(indicated in) and zero out your compound on the first groove, then use cross slide to feed cutter into work, once to depth back out cross slide and move cutter via compound to the next groove. Continue till all groves are done. Be careful of your surface speed as psdpuller said. Orrrrr

If your mill is outfitted with a rotary table you could once again find/make the right cutter and then use the z axis to get your groove spacing and your x axis for your groove depth. Easy peazy once set up.

Nice explanation Shannon! That's how I would do it on the lathe too. I would like to find an example of someone machining one with a mill and rototab. That would be a cool alternative.

Just found this.

https://www.youtube.com/watch?v=Tgzm3yHk6-M

superpsd · Feb 28, 2016

Thats chatter. Looks like you have some rigidity issues as mentioned. Make sure the lathe is up to the task first. Check spindle play and your slide play. May have to tighten the gibs up a little.

gwunter · Feb 28, 2016

ja_cain said:
Nice explanation Shannon! That's how I would do it on the lathe too. I would like to find an example of someone machining one with a mill and rototab. That would be a cool alternative.

Just found this.

https://www.youtube.com/watch?v=Tgzm3yHk6-M

Interesting video. That atlas will easily cut the grooves, but i bet it wasnt enjoying that interupted cut working that stock down. I also wonder how an aluminum pulley will wear for long term. I made an aluminum pullet for a smooth belt one time....i was very surprised how fast the aluminum wore down. Now cog pulleys are different... i fear i will have to create me a 8 rib pulley for my ac compressor on my expedition. It a 6 rib right now but id loke to convert it over.