iNf
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- Thread starter Kram
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oldbikedavey
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Oi ! That's Essexist !
Windy Miller
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Hmmm there’s a lot more to this than I’d imagined! Shame that the postage costs are nearly the same as the cost of the tool. More investigation required!
oldbikedavey
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Rumour is that Jesus may have travelled to this benighted shore, along with Joseph of Arimathea...
It'll all have been greatly downhill since, though...
Windy Miller
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So how on earth do you actually make these things? I can understand the 1.7mm hole, but how do you machine to a wall thickness of 0.04mm? That’s just crazy!
Dr.Al
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Reminds me of the line about the song "Jurasalem" - it begins with a series of questions, the answer to each of which is "no"
Nice weld there.
Kram
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If you start with 4mm bar or so, drill, ream the bore first. If you then do the OD in a single cut it generally will not matter what the resulting wall thickness is as its under no cutting forces.
How to do the rest of part? I'd likely superglue it into a bore with a brass dowel to support it will allow holding and drilling without crushing. Heat and soak in acetone to remove and hope a burr doesnt trap it.
Windy Miller
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Nah. It IS witchcraft!
Kram
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Started with endmill. I was locking the cross slide and only feeding the saddle. This one has a 18mm teeth and 16mm shank but it was only long enough for half in the collet. 300rpm
32mm endmill. Doesnt have a reduced shank but did not seem to mind going past the flutes. For next time - it would have been better to start with 32mm as it prefered a continuous cut. 230rpm.
50mm face mill could have used a bit more length, saddle hits headstock. Its a couple mm oversize as I need 47mm. 600rpm
119mm stickout with carbide bar
Im not shortening a carbide bar. Could have dug out a cheap steel one but I thought this would be better. 600rpm.
32mm endmill. Doesnt have a reduced shank but did not seem to mind going past the flutes. For next time - it would have been better to start with 32mm as it prefered a continuous cut. 230rpm.
50mm face mill could have used a bit more length, saddle hits headstock. Its a couple mm oversize as I need 47mm. 600rpm
119mm stickout with carbide bar
Im not shortening a carbide bar. Could have dug out a cheap steel one but I thought this would be better. 600rpm.
Last edited:
Windy Miller
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This truly IS dark magic!
Kram
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I have ordered a pack of CCGT03 inserts and a C06K-SCLCR03 boring bar. Should give a min bore of around 7mm instead of ~9.5mm for the ccmt06 version. The inserts are expensive £27 for 10 and £17 for the bar which is why I originally went with the 06 type.
Found that for short intermittent turing, running in reverse will throw chips the other way. A normal tool upside down would also throw chips downwards and would be better than a left hand bar, at the expense of not seeing the cut..
Was not too happy how it looked after grinding the other block off.
Looks a little better now apart from the top weld, however thats mostly where the 3.2mm rods melted and undercut and the fill above that is mostly sound.
Found that for short intermittent turing, running in reverse will throw chips the other way. A normal tool upside down would also throw chips downwards and would be better than a left hand bar, at the expense of not seeing the cut..
Was not too happy how it looked after grinding the other block off.
Looks a little better now apart from the top weld, however thats mostly where the 3.2mm rods melted and undercut and the fill above that is mostly sound.
Kram
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Cut the bottom to have clearance on the mounting plate.
I should have done the welding before the bore. Both parts were 29.97mm with no play, after welding distortion and re cutting the bore is 30.00mm. I may drill and tap the side of the bore for a brass screw to take up the play and also give me a way to lock it.
Collet chuck helped get it roughtly centered.
To dial in something that is out of round! It was only 0.03mm out. Chuck made it easy.
This part is nearly done. After the locking screw or superglue, I will drill a hole for the tool at centre height.
As I had the big chuck in, bored and turned the test peice to correct size. @Onoff next task is to glue the helical guides to the bar, then it can be milled.
Onoff
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I'm very much in awe of whatever it is you're doing. Is that welded up bit to do with my bit? If so them you're certainly going above and beyond!
MattF
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Kram
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Its not unless you want radiused ends on it?
However this is. Radius cut for handle and brazed on, and a key - used stainless for that as I had a bit of 4mm.
Onoff
In the land of the unfinished project I am King!
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Its not unless you want radiused ends on it?
Perhaps just a small chamfer?
I'm still lost as to what those last two pictures show.
