How do I make...

...the round bit on the following?

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The hole is 4mm dia, the round bit is 8mm dia. The round bit forms part of a friction hinge - it bears against a bit of rubbery stuff to ensure that the thing being tilted (bicycle headlamp) stays in the position it's set to.

I could file it and probably get reasonable accuracy, but I was wondering if there's a way to machine it. I have a mill and a lathe. No fancy milling cutters. Material is aluminium. The best I can come up with is to turn a 4mm pin and hold that in a vice on the mill, while I take light cuts by rotating the thingy around the pin with it held in vice grips or similar. Is there a better way?

Reply to
Wally
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This could be done easily if you've got a rotary table; fit a 4mm mandrel (the pin you suggested) and clamp it in the vice or, better still, in a chuck mounted on the table. Use a long milling cutter so that you can make the cut without repeatedly plunging the cutter. Martin

Reply to
Martin Whybrow

you need a a radius cutter.........some do half a side a time and some do the whole lot. it's called a concave radius cutter horizontal milling machines or horizontal milling atatchment for a vertical millwill give you the whole profile with a full rad cutter. if you just have a vertical mill ..you will have to do one side at a time.

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btw ive just had to instal solid works just to see that diagram of yours ......... not many people on this forum are going to see it . all the best.......mark

Reply to
mark

No idea, according to the link I have to run Internet Destroyer, sacrifice two goats, one sheep and let Gert hold my cheque book.

No contest, so without seeing the drawing I'll guess at using putty ?

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

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Reply to
John Stevenson

I kinda figured that, but I don't have one. :-)

Reply to
Wally

Yeah I'd thought of one of those, but I'm trying to avoind buying a special cutter for a one-off.

Comes up blank, but a search on their site for "4mm radius cutter" produces something for $66, which is more than a proper bicycle light would have cost. :-) I'll do some web-troffing in case there's something cheaper to be had.

Not SolidWorks, but eDrawings - the document sharing part of SolidWorks (I assume it asks the user if they want to install the eDrawings ActiveX control).

Reply to
Wally

Yep ...asks you to download a solid works active x file.

Got my vertical radius cutter off ebay for about =A310 {one inch radius)..this does a quarter of a circle at a time. But horizontal profile milling cutters are available on ebay all the time dirt cheap. you can often see lots of 10 that go for less than =A320. so....................................... buy a cheap horizontal milling machine off ebay..but...snag horizontal milling machines on ebay now ....are not cheap...........it's weird sometimes you can have a few weeks were they almost go for nothing ...under =A350.......then there is a glut on them and they all sell expensive..=A3350 and above. just wait ebay out and look for daft auction end times. all the best....mark

Reply to
mark

I think the way you have described is perfectly feasible:) Look here to see it in action (wmv movie), and no its not me, its the clever little Japanese guy again

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Peter

Reply to
Peter Neill

I think the way you have described is perfectly feasible:) Look here to see it in action (wmv movie), and no its not me, its the clever little Japanese guy again

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Peter

Reply to
Peter Neill

Alternatively, depending on what size it is I've got a 1/4" corner rounding cutter I could pop in the post to you, just so long as you promise with no crossed fingers behind your back to post it back when you've finished:)

Peter

Reply to
Peter Neill

HE HE HE....prepair to loose your arm ........ not for inexperieced..me thinks Wally would have to have an extra long endmill for that job............. all the best.........mark

Reply to
mark

I think I'm convinced. :-)

I made a copy of his t-shaped flycutter recently and stuck a carbide lathe tip in it. Did this with it...

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Reply to
Wally

Thanks, but it has to be 4mm radius - it's to fit into a ready-made light unit (Maplin head torch for an amazing 5 quid).

Reply to
Wally

That's a bummer.

It's okay, the Japanese guy has demoed the method I was thinking of, so I'll give it a go.

Reply to
Wally

Nah, it's ally - light cuts, no-jumpy-uppy holder, and leather gloves. :-)

I need a flute length of 20mm, which I might have. I can plunge the cutter if I have to (I'm not making swiss watches).

Reply to
Wally

Add the radius of the cutter to the radius of the round bit, calculate the Sin and Cosine at various regular angles, pich out to these dimensions, and plunge down at each point. On such a small radius, using an 8mm cutter and 9 degree increments will require few presses of the caculater buttons and will produce a fairly good radius requiring little more than a rub with a stone to make good.

Hope this makes sense.

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Reply to
John Woodison

Aye, always worth a look on eBay for tooling...

I don't really have the room for any more machinery - half of my spare room is the (mini) machine shop. Agreed on the eBay price weirdness, though - it pays to keep an eye on the thing of interest for a while, to see what the prices do. I picked up a Cyrus hi-fi amp for about a fifth of the going eBay rate a couple of months ago.

Reply to
Wally

If its only light alloy ...then a router bit will do. they are plentyfull and cheap .........there's some in aldi now . all the best...mark

Reply to
mark

I've done this with steel. I saw an experienced friend do it and decided to have a go myself. The lever was about 350mm long and, with light cuts, the cutting force was _much_ lower than I anticipated. It looks scary, but it turns out to be a non-event really.

Reply to
Gary Wooding

Just buy a R4 corner rounding cutter. It'll be the quickest way, are you intending to make more than one?

Just took a peek in the J&L catalogue. MRC-04140A @ £12.33

Not that "fancy" a cutter!

Wayne....

Reply to
Wayne Weedon

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