Drilling the pistons
 

Hy,

in several set up sheets, the pistons are "drilled" to achieve a greater diameter.

As far as I could "find out", the standard diameter in my CAT AERO and in my Cougar KF of the holes is: 1,5mm. (at least this was the diameter for which i could feel some "resistance", 1,4 was too small, 1,6mm show "massive" resistance).

I am not a pro driver, nor is my son (14, but he is racing for several years now). But a good set up is always a great thing, so I decided to go for some "drills" in this dimension.

I have always used (in my former CAT SX, SX2 and SX3) the pistons with 2, 3, 4, 5, 6 holes), but I found, that the 3-wholes worked best...

Anyway: I just want to let you know, that i found a supplier for drill bits. CORE RC offers a set for drill bits until 1,5mm (RC233), this is out of stock in germany. (CS-electronic). And, unfortunately this does not help:(

My supplier offers all drills, like, 1,5, 1,6, 1,65, 1,7, 1,75, 1,8.... if you want in a very nice box....

I don`t know, if i am allowed to publish the name (I have nothing to do with them) or to set a link to their online shop here. Let me know

The core kit is in stock at Schumacher:
http://www.racing-cars.com/pp/Manufa..._RC/CR233.html

I was thinking about getting one of these, but not done so yet so can't comment on the quality:
http://www.ebay.co.uk/itm/2609759308...84.m1438.l2649

If the set is in stock in England it does not necessarily means, that it is available in germany at CS-electronic: here

About your set: see, this is a set with drills of 0,3 - 1,6mm. But you need 1,5mm and higher.... So the only drill you will use is the 1,6mm one.

What I found is a bit more expensive: http://www.fohrmann.com/spiralbohrer...n-din-338.html please choose the second set with the drills 1,3mm - 2,2mm.

It is a bit more expensive. But I guess, it is the same. And on this page, you can find all "HSS Bohrer" =drills in the dimension 1,65mm,http://www.fohrmann.com/hss-bohrer-4200.html too.

Great, thanks for the information :thumbsup:

Cromwell Tools can supply virtually any size of drill bit in the UK overnight, I have just got my 1.65mm drill bits at 98p each!

try here always had a good service from them http://www.modelfixings.co.uk

To let more oil thru the pistons could not try 4 hole pistons instead?

and they want silly money to post to the uk?

Sure you can use 4 holes.

But the pistons with 3 and 5 holes are "rounded" at the outside and so they simply work "better" than the ones with 4 or 6 holes.

And sometimes you want to have a bit "less" damping, or a "quicker" reaction. And so, as always: either drill or change the oil.

The jump between the 3 holes and the 5 holes is pretty big.

Please see the chart:
diameter/area
1,5mm: 5,3mm^2
1,6mm: 6,03mm^2
1,65mm: 6,41mm^2
1,7mm: 6,81mm^2
1,8mm: 7,63mm^2
1,9mm: 8,5mm^2
5 holes: 8,8mm^2

A perfect matching list.....

Never forget: not everyone in this forum is living in the UK. But correct: the shipping to the UK is very expensive....

Today I got my full drill set! 1mm - 2,2mm, plus 1,65mm and 1,75mm.

Ready to drill holes!

carb jet drill kits will usually go from 0.1 to 2mm in 0.1mm and 0.05mm steps