Easiest way to polish inside of an aluminum cylinder?

[jmccalip]

Alright, let me start out by saying I am a newbie to everything involving machining.


At the shop I work out we get the same parts every month, and we need a faster way to polish these parts. They are basically(I don't have the drawing scanned...) aluminum cylinders that resemble a round vitamin bottle about 3.00" long and an inside diameter of approximately 1.00". The only area that needs polishing is the bottom inside face. What we usually do is just put the parts in a lathe, and then we use paper towel that is tightly wrapped around a wooden dowel to insert into the part and polish the inside. The problem is, it takes about 2 minutes per part, and we have hundreds to polish. Is there a special cloth or tool that we can use to make this process go a little faster?

Would a polishing compound work better? I have experimented with WD-40, diesel, dish washing soap, ect. I have found the soap works best because it does not leave residue behind, but the finish lacks behind the WD-40. Anybody have some tricks? Thanks!


BTW: I really wish it was possible to use the Puma 240 to polish the parts by itself!

[fuzzyracing1967]

just wondered what kind of surface finish are you looking for?

[jmccalip]

So the scratches are gone and you can see a blurred image of yourself reflecting back.

[holbieone]

try tooth paste

[g30u0w0]

So the scratches are gone and you can see a blurred image of yourself reflecting back.

Have you looked into getting an internal diamond roller burnishing tool? Not sure how it works on aluminum, but beautiful finish on steel. very application specific. One pass-mirror finish could not possibly take more than 10 seconds per foot. Why can't you use the Puma?


You know what works really well for hand polishing applications is Burns red rouge on a porous cloth(cheese cloth). Buffing compound to be exact. Cuts really well/fast and leaves a finish that is ready for plating it's so good.
Other things my shop uses for polishing-
clover compound-Mcmaster
Lapping compound GK-10 very fine-United States Products
Buffing coloring compound-buffing supplier
crocus cloth-mcmaster or sandpaper Inc.
Personally, if you want a top notch finish for hundreds of parts I would rig a way to CNC it and get a burnisher. Cost you 500-800 for tool but NO WAY will take 2 min/part. Even if your chucking operator was takin' his sweet time. And you could never get the same finish by hand. If you absolutely can't cnc it start with the crocus cloth-no real cleanup.
Hope that helps. let me know the story on why no CNC.
G30

[dertsap]

take a peice of scotchbrite and cut out circles , find a long 1/4" machine bolt ,cut the head off and insert that end into a die grinder ,at the other end use two nuts to hold the scotchbrite circles in place and you've got a great polishing tool ,the more of a stack of scotchbrite you do the better it will be and the more it will squish and cup over the nuts so they don t accidentally damage the material
a little cutting oil and a bit of wear on the scotchbrite you'll achieve a good finish with minimal if any material removed

[High Seas]

Not to send you off-site, but have you checked out Caswell Plating? They have a forum there that specializes "in the buff" stuff!
http://forum.caswellplating.com/forumdisplay.php?f=7
Have you tried a compound - I have been using the green and the white in an angle grinder and very tarnished/corroded bronze -- AMAZING!. They might have some small "buds" to get in the small "beer can".
Jim

[fuzzyracing1967]

I'd have to agree with dertsap,but maybe consider just holding part and having scothbrite on a stick in a hand held drill?

[lerman]

It sounds like you are chucking the part and holding the wooden dowel in your hand.

That sounds backwards to me. Try chucking the wooden dowel or whatever you find best for polishing and holding the parts in your hand. That should save a lot of time.

Ken

[jmccalip]

Thanks for the replies.

It sounds like you are chucking the part and holding the wooden dowel in your hand.

Exactly. I just run the spindle manually at about 1200RPM.

Why can't you use the Puma?

Well, I don't know the specifics exactly... I'm only 17 years old and more of a button pusher. I haven't actually asked my boss why we don't CNC the polishing. I just assumed if you used a soft material like cloth, it would be a nightmare adjusting the offsets to keep the pressure on the part equal every time( doing the work by hand, I have to reform the end of our homemade "polisher stick" every couple parts to get a good finish).



I was looking up the Burnishers online, and they look perfect for the job. Specifically this one:




I just cannot figure out why they cost $500 though???

[g30u0w0]

The picture of the tool you posted is the correct concept. I would shop around and look. Ask a lot of questions before purchasing. How does the tool work on aluminum? Make sure it coincides with the diameter hole you need to penetrate and can cover the surface you want to clean up. (that's a duh, but thought I'de add it).

I like the scotchbrite idea, sounds easy and much cheaper.
You can get that at Mcmaster too.
They also have sanding sponges that come in really fine grit.
I also agree with the "chuck up your stick and hold the part"
Just be careful. No gloves, no long sleeves, and wear glasses. And do not let anyone tell you they made a great "wrench" to hold the part in while you do it by hand. Seen that go bad more than once. Low rpms good idea. Last thing you want is an aluminum bottle in the face. that might f^$k up the rest of the day!
Hope that helps.
Chris

[cam1]

Brasso works great on Aluminium!
Fine Scotchbright with a little Brasso works really well.

cheers