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preping semi rigid


militaryoperator
 

What's the best tool to prep semi rigid coax with?

Been using my Stanley knife but is there something easier?

Ben


Robin Szemeti - G1YFG
 

I use a stanley knife.   Roll the cable on the bench, pressing down with the blade just to score the copper, then bend with a pair of pliers and it breaks on the line.


On Sat, 26 Sep 2020 at 20:34, militaryoperator via groups.io <Military1944=aol.com@groups.io> wrote:
What's the best tool to prep semi rigid coax with?

Been using my Stanley knife but is there something easier?

Ben


--
Robin Szemeti - G1YFG


Neil Smith G4DBN
 

I had a number to make up, and although using a miniature rolling cutter for brake pipe worked, in the end I got bored and put the coax lengths in a collet chuck and used a knife-edged grooving tool to turned the outer tube and PTFE off almost up to the centre conductor, finishing with a scalpel so I didn't nick the silver plating.  It felt very silly, but the result was perfect.

I made up a jig last year which consisted of a split piece of round stainless, reamed to the right ID of the semirigid, and fitted with a clamp screw. I made a mandrel to mount a Dremel citting disk with a stepped boss just the right size so when I ran it round the outside edge of the large cylinder, it would cut through the copper and most of the PTFE.  it was a bit fiddly to use though.

Now I have a toolpost spindle, the collet solution is very simple, just pop a Dremel disk in the spindle and turn the lathe slowly, advancing the cross-slide.

Th brake pipe cutter worked pretty well though. https://www.toolbayuk.com/products/sealey-vs0349-brake-pipe-cutter

Neil G4DBN

On 26/09/2020 20:45, Robin Szemeti - G1YFG wrote:
I use a stanley knife.   Roll the cable on the bench, pressing down with the blade just to score the copper, then bend with a pair of pliers and it breaks on the line.


On Sat, 26 Sep 2020 at 20:34, militaryoperator via groups.io <Military1944=aol.com@groups.io> wrote:
What's the best tool to prep semi rigid coax with?

Been using my Stanley knife but is there something easier?

Ben


-


Pete - GM4BYF
 

I use a copper pipe cutting tool - the sort where you insert the pipe and rotate it. Cutter needs to be sharp and apply only light pressure so the end does not get bowed inwards.

73
Pete GM4BYF
On 26/09/20 20:34, militaryoperator via groups.io wrote:

What's the best tool to prep semi rigid coax with?

Been using my Stanley knife but is there something easier?

Ben


--
vry 73
Pete GM4BYF


Chris Bartram G4DGU
 

I've used the 'Stanley Knife' technique for years with good results on semi-rigid and semi-flexible cables from 0.25 down to 0.047in. It does require a certain amount of delicacy with the smaller cables, though. I have tried a small diameter pipe cutter, but didn't like the tendency it had to 'bend the edge'. That led to return-loss problems and was particularly obvious when I looked at the results under a low-magnification microscope and with a net.an. The length of the bends was starting to approach a significant fraction of a (guided) wavelength at 10GHz and above.

73

Chris G4DGU