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View Full Version : Polishing out Cast aluminum Harley wheels???



ibewgypsie
10-02-2003, 10:18 PM
I have six or seven of the Fatboy style cast wheels. I chucked on in the Cinncinatti lathe and cut it down, then hooked a toolpost grinder up and tried to buff it..

Problem is.. I did one side, the tool chattered leaving wavy marks in the aluminum.

I sent the test wheel (monday) to a Diesel truck wheel polisher. He kept it for this week, brought it back with a $25 materiel request.

It looks very little in polish than when it left. He said he burned out two buffs.

HOW TO REMOVE THE sand CAST marks? Should I try to run it on the indexer and the mill or would that leave tooling marks too?

Any suggestions would be very welcome.

Flapper sandpaper wheel? what?

Cass
10-02-2003, 11:37 PM
A polycrystalline diamond insert will do a lot better job on cast aluminum than carbide. Use oil coolant and the diamond will cut much cleaner. 3M makes some fancy sand paper they call Tricut or something that has the abrasive in little pyramidal bumps. They claim it is very good on buffing/grinding/polishing aluminum etc. but get the wavy marks out first with a diamond tool. They are expensive so you might try to get one for trial use and buy it if it works.

Paul Gauthier
10-03-2003, 08:21 AM
Wierd

Try a large radius on your tool, (pun intended). Seriously a large radius like .125 ir better .250 and a feed rate of no more than .005 and you may have to back up the center of the wheel somehow to prevent chatter. This may give you a beter finish, certainly it will be easier to polish with that tricut that Cass mentioned. Polish with succesively finer grits. I have found that buffing alum. is more of a pita than its worth. I buffed a kick start cover for my neighbors 59 FLH and I did not like it at all. It was a poor casting to begin with, porosity kept popping up everwhere. Spent about 8 hrs. on it and finaly got it to where it was not half bad, but it would not shine worth a damn.

------------------
Paul G.

Thrud
10-03-2003, 08:31 AM
Dave

To get nice cuts with a Diamond inserts you need to run the lathe at maximum speed - this will probably still be too slow. If you can muster the correct SFM (1K-2K) the aluminum will come out with an irridescent sheen which is far easier to polish out. You should be aware tht you may be beating you face in a brick wall - the casting may just be too ****ty to make them look better - this is why billet is used for custom wheels - no inclusions, easy to polish.

ibewgypsie
10-03-2003, 10:31 PM
Howdy..

If I can get it close..

I learned a old trick about 30 years ago.. You take brown paper bag and simichrome polish and it is abrasive and the amonia makes it shiny.. Simichrome is great on aluminum. Nothing else works as well..

I used to polish the harley all winter.. it'd look like chrome.. tarnish easy thou..

I rubbed the chrome off the first bike. I appreciate the powder coat, squirt and ride type of bike now..

Techtchr
10-04-2003, 05:51 AM
We use to use black rouge to "color buff" soft metals like pewter and aluminum. It won't get out the waves from machining, but it will give that final mirror finish. Red rouge will work too but it is more difficult to clean off the buffing dirt when you are done. Buffing and polishing is tough on some items. A good buffer can bend a spinning 10 or 12-inch buffing wheel into places that us normal humans could never go. My only other suggestion is to machine it with as smooth a finish as you can muster, and then buff it in stages. You may have to start with something coarse like emery compound and work your way through to the rouge. Buffing is a messy nasty job, that's why when I do it I make sure I get paid well. $25.00 sounds like a bargain if he spent a 1/2-hour and destroyed two buffs.

Ibew, I have a few (used) air-way buffs I'll sell to you for the price of shipping if you want them. They are about 12" in diameter and fit on a 1" shaft. They have metal centers, so you have to use them with a couple of 4-5" washers on either side. We use to use them for buffing Tuba bells and parts.

The other solution; put'em on e-bay and let someone else worry about making them shiny,that's a heck of a lot easier and you'll probably get as many dollars.
Matt

ibewgypsie
10-04-2003, 08:19 AM
Techtchr..

Yes, I'd like the buffs.. Do you have a paypal account? email me..

We plan on building bikes with the wheels, not selling them. I am cutting designs in them with the mill.

Near disaster this weekend. I bought all the tubing to bend more frames, hired a welder, a laborer. Tubing was delivered wrong. They dropped square tubing....... THEN, a show quality tattoo, the guy requested SHOW QUALITY inks, ($400+shipping) and I overnighted it after he paid for them. It still has not arrived. He will be here 9am and won't be happy. His arms are the size of my thighs too. (28+ inches)

I bet they used FEDEX, the worst shipper available locally. They left a $22,000 dollar check on my porch with a rock on it in the rain. Left my castable refractory in the rain another time. Have called me twenty or more times saying they can't find me and want me to come to the terminal to pick up package 30 miles away.

People make a business. They tell me UPS acts like that in California.

Not being able to deliver (them or Me) for any reason is unacceptable in my book. I may loose a high dollar customer today. Will have to pay the welder and laborer show-up money.

[This message has been edited by ibewgypsie (edited 10-04-2003).]

ibewgypsie
10-04-2003, 08:29 AM
I have some high end large dia mills, I will try cutting 10-20 thou off the other side, even if it leaves swirl marks with the mill it is better than the cast marks. MAYBE? a high liquid flow for chip removal as much as cooling?

DO I need to cut slow or high speed? I noticed cutting letters out in billet saddle bag inserts a high speed is slicker finish with a 1/8" mill.

Thrud
10-05-2003, 03:53 AM
Use lots of coolant and the highest sfm you can muster - 1000-2000sfm is the recommended range for Aluminum & inserts.

Techtchr
10-05-2003, 08:36 AM
Ibew,
I'll box them up and we'll worry about shipping cost later. I have a paypal account but I have never taken payments that way, only paid out. I don't like it when paypal has too much knowledge of my account numbers, so I won't relinquish my bank account numbers to them.

I had UPS deliver some books to me a couple of years ago. After about a month of waiting the book company finally sent another shipment after I complained. I found the original box in my yard after the snow melted. Luckily they were shrink wrapped and un damaged.

Matt