Best way to radius rod ends

[nigelh]

Hi folks,
I've reached the stage with my Simplex valve gear where its time to radius the ends of the various links.
I don't have a rotary table or milling machine and wonder if any one has done it safely on the lathe (mine is an ML7) using a milling cutter and, if so, any hints/tips, to avoid the rod "catching up" would be appreciated!
In Martin Evans "words & music" on the Simplex, he mentions using a small Runbaken grinder to get a better finish but I can't quite picture how that works - I must be suffering a mental block! Has anyone seen a drawing of his setup?

Any help/advice would be appreciated,
Thanks
Nigel

[Deleted]

Nigel

I tried LBSC's method of swinging the rod end on the lathe, and also used a rotary table. They are both loaded with potential disaster!

I have now found the ideal method for me: case hardened bushes and filing, leaving the necessary bits 'proud', and finishing off with sanding drums in a high speed pillar drill.
If you've seen my brit pics the rods were all done that way.
JB

[donashton]

NEVER mill anything that is not bolted down well. The 'catching up' will always catch you out, ruining the milling cutter, the work piece, and almost certainly you as well. Have patience and take JB's advice.

It is possible and quicker to rotate by hand on a vertical linisher after roughing out. Cut an arrowhead on the end of a hefty block, say 1 1/2 x 1/2 steel and put in a pin at the apex on which to rotate the rod. Just hold this all flat on the linisher table and use a belt about 1/4" wide. Any catching up force is minimal.

But then you need a linisher!

Don

[gdd]

I made a mini drum sander by mounting my Dremel under a horizontal surface with the sanding cylinder sticking up. I milled freehand roughly to the line and finished it freehand on the Dremel. I was surprised at how quick and effective it was. I reckon the finished job was as good as you'd get any other way.

Graham.

[nigelh]

Hi guys,
very many thanks for those words of wisdom - I really was a bit concerned about ruining my hard won links at the last stage!
Looks like a drum sander of some type is the next project then.
Thanks again for the help,
Nigel

[greensands]

If you do decide to build a belt linisher I would strongly advise you to consider making one that works in the vertical mode as you will find them to be more versatile and easier to use than the more common horizontal models. A word of warning though, a belt linisher is a very effective remover of metal but you do need to take care to ensure that the work remains square at all times to the belt otherwise you will end up with rounded edges.
Reg

[Deleted]

Nov 22, 2011 9:59:12 GMT greensands said:

A word of warning though, a belt linisher is a very effective remover of metal but you do need to take care to ensure that the work remains square at all times to the belt otherwise you will end up with rounded edges.
Reg

Reg is indeed correct about the removal rate, especially with a 60- 80 grit belt! I also have a 240 belt which is a whizz at fine finishing flat surfaces. I made a 100mm sq 25mm thick iroko work table for my ancient Clarke linisher and screwed it onto the tool support thingy, and the angle is adjustable. In the vertical mode the machine has largely replaced hand filing.
JB

[davidm]

I did mine on the lathe (ML7R), because I didn't know better! I can confirm that you can quickly mess up an otherwise beautiful bit of machining and your hand (a bruise but no lasting damage). I still say that WITH CARE, with the pivot a good fit on the bush, and taking very fine cuts you can do it OK, but I must agree that it's not the safest method. A rotary table is by far the best way.

David

[pault]

Hi All
You would be surprised how quick you can do the job with filing buttons and a good file it makes a good job of them, and it’s totally risk free.
Regards
Paul

[gdd]

Have a look at this:

www.modelenginenews.org/restored/conrods.html

Graham

[nigelh]

Hi Graham,
thanks for the link - that seems like a good method and solution, so long as one has a mill.
I wonder if it could be adapted to a lathe - it's got me thinking!
cheers
Nigel

[brozier]

Hi Nigel,

I'd say this method would actually be better on the lathe as you don't have the table in the way. ;D

Bolt the block of ally/steel to the cross slide and rotate the rod in the horizontal plane rather than vertical. Simples!


Cheers
Bryan

[nigelh]

Good thinking Bryan - with the top surface of the block of ally/steel, which the link to be radiused is mounted on top of, at centre height, if I understand you correctly ?

[russell]

Using filing buttons is quicker than setting them up in the lathe or mill.

Russell.

[brozier]

Hi Nigel,

Near to centre height was what I was thinking obviously it would depend on the diameter of your cutter and the thickness of the job but as long as they overlap the height of the block is not critical.

Russell is right that filing buttons is another way of solving the problem but you'll need decent Silver steel of the right size and a torch for heating. Depends on what you have in house....

Cheers
Bryan