Radius Fixture

A video on Youtube showing the manufacture of a fixture for milling a radius. And as the operator in the video says, a bit over the top but he shows a lot of interesting machining techniques.

Nice fixture, I tend to use my rotary table. I guess this was the video.

Thor

Very impressive … but plenty of opportunities to make an expensive mistake.

MichaelG.

Quite agree with MichaelG. Listen to intro. on video, hear producer saying he couldn't be bothered to hump heavy rotary table on to mill to do a rounding job. Then he goes to all that trouble to make what I think is a poor mans rotary table! He demonstrates a rough and ready linisher method, which if carefully done, will, in my opinion, be adequate for most purposes. An easier way of getting better results would be to have a leadscrew controlled slider with a number of interchangeable vertical pegs, one to fit hole in work. Slider would incrementally move peg nearer to sanding belt while moving the job by hand, around the peg.

My thoughts are the whole idea is willy waving - "look what a clever machinist I am." Or am I missing something? Can't remember last time I was accused of being thick!

I ‘potentially’ need to make some parts with precision curved sliding fits. I’ve never even considered doing it before now, but maybe if I could make this fixture, I might be able to attack such jobs with a tad more confidence. I await the vid on his results and usefulness, but somehow doubt I would manage anything to the precision he seems to set for himself.

In summary, probably too good for my skill level - so it’s likely never to be followed up.🙂

MEW did this in one of the early issues. Made mine in Stainless - cos I had access to it.

Regards Ian.

Looked at the first 20 seconds. May watch more this evening. However looks like he never heard of filing buttons though I admit the problem with them is you never have the right size or remember where you put them. I'm thinking nowadays they could be knocked out as single-use-plastic in a 3D printer.

Very similar in principle to the ungeared small rotary table designs of G H Thomas and Harold Hall, published in ME and MEW respectively.

But he missed the very simplest way of machining a radius on a corner or end of a rod that has a hole in it. You can hold a pin upright in the mill vice and slip the hole in the rod over the pin then hold the end of the rod to pivot it around while milling the radius with an end mill cutter.

Bit of a dodgy trick but sometimes used in jobbing shops where time is of the essence. And homeshops (like mine) where laziness rules. This video shows the principle: Actual machining starts about 00:40.

Apart from the lifting bit (is the new one much lighter? ) A sub table on his existing R/T and disengaging the screw would have done all that. Usually even room to add adjustable stops to a table that size

The loss of height from mounting it in a vice will be a big disadvantage for many a hobby mill user where they are often challenged for head room.

Edited By JasonB on 12/06/2023 12:18:18

A pin in the hole and held upright in a vice is what I normally do (if small enough to fit in the vice) and a touch up on a belt grinder to smooth. Otherwise clamped to a simple plate that is bolted to a rotary table. He did show a couple of good machining techniques like a trepanning tool and using masking tape and super glue to hold the work.

It's a lovely job he has made of it, and definitely easier to lift than the big rotary table. I have the two pieces of steel to make own version, a la Harold Hall, but they have been sitting on the bench for six years now. Ended up buying a little 75mm rotary table with worm and wheel and all for less than $100 so lost motivation to spend $1000 worth of time on making one.