Well-Known MemberHMEM Supporting Member
- Dec 31, 2010
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Great work as usual Terry. You might have mentioned in the past - but how do you cut your gaskets?
Dave,Great work as usual Terry. You might have mentioned in the past - but how do you cut your gaskets?
That's the term I was looking for!A drag knife I think it's called - No?
I'll have to give that a try.
Amazing work as always! So you use a 4 flute cutter on aluminum. I use a 2 flute 1/16" cutter when I really need detail machining, but do break them now and then, especially if I try anything like a .030" DOC. I thought a 4 flute would plug easier when cutting aluminum. I do use a mist system. Maybe my cutters aren't the best quality.The outside surfaces were machined using 1/4" roughing and finishing cutters, but the topside with its .075" raised lettering was designed around a 1/16" end mill. The font (bold Source Code Pro) and its size and spacing were selected especially for this cutter. The machining time on the 10 square inches of topside real estate was reduced to a reasonable one hour using Tormach's Speeder which is a 3X spindle speed multiplier for their 1100 mill. Using a .030" d.o.c. and running at 13k rpm, the tiny four flute cutter was pushed at a leisurely 9 ipm.
Mike,Terry - by any chance is the drag knife that you use?
Drag Knife for CNC routerThe Donek Tools Drag Knife can be used to cut almost anything you would cut with a utility knife, but with the speed and precision of a CNC router.donektools.com
Are you using a course enough blade? I have a chunk of 3" thick aluminum of unknown grade that I had trouble cutting; blade drifting a lot. I switched to a course tooth blade (can't remember off hand, but maybe 6-8 tooth) and the cuts were dead straight after that.However, it doesn't seem capable of accurately cutting thick sections of this stuff. I've tried readjusting the blade guides, but the kerf invariably drifts outward nearly half an inch in a three inch deep cut. On one occasion the tension increase broke a bimetal blade.
You're right. I'll likely add one to the plug keeping an eye on poles.Amazing work on this engine
Was thinking that the magnet would be better embedded in the sump plug this way any material stuck to it can be removed easily
I tap the holes manually using a shop-made tap block - nothing complicated, just a block of Delrin with a hole drilled in it for the tap shank. I use WD-40 for tap fluid and the chart recommended 75% engagement tap drills. Gun taps for through-holes, and tapered followed by bottoming taps for blind holes. - Good luck on your full-size build. - TerryWonderful work Terry! Forgive me if I missed it in previous posts (I get sidetracked pretty easily with all your great pix..), but how are you tapping the holes in all that aluminum? Have you tried form taps? What are you using for cutting fluid? Are you just using the recommended drill sizes from the charts or are you using different sizes?
I got a message from a friend tonight who picked up an old Jeep (Willys) his father owned that has a 289 in it, it's going to be a BIG project, but pretty exciting, it'll be the 3rd or 4th 289 I'll have wrenched on/rebuilt. I'm pretty excited about that, they're a fantastic little engine. Maybe I can talk him into the Cobra valve covers & air cleaner. I don't know if I can sell my friend on the Weiand carbs like George modeled up, but boy, that would be nice.
In 7075 and 2½ diameters engagement you can likely get away with a 65% thread, yield and tensile strength are almost as high as 1018 steel.I tap the holes manually using a shop-made tap block - nothing complicated, just a block of Delrin with a hole drilled in it for the tap shank. I use WD-40 for tap fluid and the chart recommended 75% engagement tap drills. Gun taps for through-holes, and tapered followed by bottoming taps for blind holes. - Good luck on your full-size build. - Terry
I once tried a corncob mill and I seem to remember having good success with it. I have one variable pitch cutter but its only 3/8". I may revisit a corncob cutter when its time to machine the bell housing. - TerryThat's some tenacity there. Very nice!
Have you tried corncob mills or the newer variable indexed flute mills? They vary the helix indexing to reduce chatter when hogging out aluminum. I hear they work pretty good on thin-walled parts too.
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