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MG TD TF 1500 - Machining Aluminium

I am making a wood rim steering wheel for my TF following the Bluemells pattern. I have a scrap, original wheel and have turned down the central boss to accept a circular aluminium flange which I have TIG welded on. I had no problem roughing out the flange, but after welding I found it difficult to clean up the flange in my lathe. Instead of a nice clean cut I just produced chips and a rough finish. I have managed to produce a very satisfactory result with emery paper but wonder if the heat from welding has hardened the aluminium? The Bluemells wheel doesn't have rivets and the wood rim has a rebate for the aluminium so you don't see it on the outside. I propose to glue the wood to the aluminium frame with epoxy adhesive but wonder if anyone has experience of using rivets. Do they sink into the wood as they are peened over?


Jan T
J Targosz

Hello Jan . May I recommend you increase your S.P.M or S.F.M and apply coolant during cutting . A very light feed as well and make sure your cutting tip is sharp and at the right angle. Also you may want to consider using a ceramic cutting tip. They do not build up high degrees . John
J .R.C Cavey

What J.R.C.C. Said plus.
The heat from welding may have annealed the Al. This makes it soft and gummy and harder to machine.
WD-40 is a really good cutting lubricant for aluminum.
Just spray it on as you are turning.
The tip of you cutting tool should be slightly rounded. a 1/64 or 1/32 radius is good and it can never be too sharp.
Use HSS not Carbide.
JA Benjamin

I've had the same problem machining aluminium and agree with both Mr. Benjamin and Mr. Cavey. You should also check the bit carefully as you machine - sometimes a bit of aluminium 'sticks' onto the end of the cutting bit and then drags along the work leaving a rough surface. Checking and clearing the bit often prevents this.
Kevin McLemore

All the above comments make sense. About 25 years ago I used to make rear crank seal kits for XPAG engines. The process involved oxy welding bits together and them fly cutting the surfaces on a dummy block. I found that freshly welded alloy picked up on the cutting tool but "blanks" that had been lying around for a month or so cut cleanly. I thought it did not make sense and it must be my imagination until someone told me that alloy "age hardens" after being annealed by welding. The harder alloy is less gummy and machines more cleanly. Any metallurgists out there who can explain this? Bob
R L Schapel

Solution heat treatment for 6063 involves heating the part to 970 +/- 10 deg F for a period of time, depending on maximum thickness, quenching ... usually in water ... then the part must be aged at 350 deg. for 8 hours to regain T6 strength. PJ
Paul S Jennings

I never used them but some aircraft structures are fastened with rivets in an annealed state. They're commonly called ice box rivets as the age hardening is slowed for a time by keeping them refrigerated. One of my acquaintances who actually used them told me that he could tell when they needed to be annealed again as they got harder to drive. Apparently they could not be worked at all when fully age hardened.

Not being a machinist I thought softer would be easier to machine and I find it interesting that it can be too soft. Always learning on this site.
JE Carroll

This thread was discussed between 30/06/2014 and 02/07/2014

MG TD TF 1500 index

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