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| Rotary tools in support of electronics, Dremel and more .. |
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| HLA-27b:
To add a bit to robenz' write up here is a little trade secret for grinding aluminium. Once I was involved in design and production of a new façade for an office building which consisted of nearly 20 tons of aluminium sheets welded up - all welds to be ground flush and polished to match the original finish. My guesstimate is that we removed close to a ton of aluminium by grinding alone. So I had enough time to go though all of the Murphy's laws concerning aluminium and its grinding. Aluminium is very nasty to grind with abrasives as it fouls up the abrasive immediately and once fouled the stone (or flap disks in our case) can not be recovered. One little known remedy is to use lard as a lubricant. Yes, common lard and I know it is 21'st century. Liberal amounts of animal lard is applied to the part being worked and the grinding medium. As the part is being worked it heats up and melts the lard which then flows and lubricates and almost totally prevents fouling up of the grinding medium. I've experimented with most other substances out there and nothing works anywhere near as good including all sorts of oils greases emulsions suspensions old wife remedies and what not. It makes an absolute horrid mess as blackened drops of molten lard sling all around and solidify as they hit the wall and ceiling, so be warned this is not something you want to try in the living room. Wear goggles and some old t-shit you don't like. Lard is a hard white substance with consistency reminiscent of soap or candle wax (i.e. it is purified not raw). It should be available in hardware stores if lots of aluminium is being worked around the area. It is also raw material for common soap. |
| robrenz:
I use Johnson's #140 stick wax. It is made for this and behaves exactly like the lard including the horrendous mess. Also works well for using carbide burrs on aluminum. You can dip the running burr in the wax. My tube of it is probably 30 years old but it is still available. HAL-42b, I am glad we can count on each other to get OT in the machining direction :) |
| HLA-27b:
--- Quote from: robrenz on July 06, 2012, 07:07:13 pm ---I use Johnson's #140 stick wax. It is made for this and behaves exactly like the lard including the horrendous mess. Also works well for using carbide burrs on aluminum. You can dip the running burr in the wax. My tube of it is probably 30 years old but it is still available. --- End quote --- I'm kinda glad that we don't have "everything brand name" around here yet. Most things are sold as bulk commodity. Or maybe it is simply due to the quantities that I am used to deal with. --- Quote ---HAL-42b, I am glad we can count on each other to get OT in the machining direction :) --- End quote --- It's a pleasure :) |
| SeanB:
One of the hardest things to machine is soft silicone. PTFE is a far second, and Vesconite is great to machine bushes out of. Much better wear properties than bronze, and nice to work with, though you have to be careful with thin sections, you need sharp tooling and multiple small passes to get to the final size. |
| T4P:
As for picking the right rotary tool ... Forget about dremel If anything avoid the ones that look like the dremel normal series Go for the ones that have a 25mm chuck or a 6mm chuck PS: I'm throwing out my dremel clone that hardly works anymore once i get a new die grinder |
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