AndrewMAshton Posted January 14, 2011 Report Share Posted January 14, 2011 Hello, also on the winter jobs list (growing by the day) is fitting an oil cooler, I need to cut 3 of approx 2" diameter holes in the valance to get a flow of air through the oil rad, once the holes are cut I am going to fit the Revotec Air Inlet Duct to make a neat job, my only problem is fairly major, how on earth do you cut a 51mm dia hole without the cutter wandering all over the front valance, you guessed it, tried once before, disaster! As always, your advice gratefully received, Andrew Quote Link to post Share on other sites
Steve R Posted January 14, 2011 Report Share Posted January 14, 2011 Andrew This sort of thing shoud do it, you drill a clearance hole for the bolt, put the two halves together, then tighten it up, cutting the hole. http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0543787 Regards Steve Quote Link to post Share on other sites
stuart Posted January 14, 2011 Report Share Posted January 14, 2011 For the price and quality you couldnt beat this set. Bosch holesaw kit. I use this type of cutter for bulkhead holes and they do a great job with the pilot drill for starting so no wandering Stuart. Quote Link to post Share on other sites
Guest ntc Posted January 14, 2011 Report Share Posted January 14, 2011 For the price and quality you couldnt beat this set. Bosch holesaw kit. I use this type of cutter for bulkhead holes and they do a great job with the pilot drill for starting so no wandering Stuart. Yep and clamp a piece of wood behind Quote Link to post Share on other sites
Chilliman Posted January 14, 2011 Report Share Posted January 14, 2011 I've got a couple of these kits which work very well - but as Neil said use a piece of wood behind - it gives you an accurate guide hole and stops the main cutter edge from wandering so you get a clean cut Quote Link to post Share on other sites
ianc Posted January 14, 2011 Report Share Posted January 14, 2011 My experience with the RS type of cutter was that there was a real danger of distorting the sheet as the compression was increased, and the torque required for a 2" hole is not insignificant. The distortion occurs for two reasons: the face of the cutter (see picture in RS catalogue) is curved, and one has to twist the head in order to force the cutter through the material. Such cutters work quite well for small to medium holes on softer material, such as aluminium, with a reasonable thickness (1/16" or more). When I was an apprentice (aeons ago!), we used them to cut the holes for the bases of thermionic valves when making prototype electronic circuits. On the other hand, the Bosch type of cutter requires very little force to be applied (as long as the teeth are sharp and the drill is spinning rapidly), so no distortion of the sheet should occur. Ian Cornish Quote Link to post Share on other sites
RogerH Posted January 14, 2011 Report Share Posted January 14, 2011 The RS cutter described above should be able to punch through 19swg without distortion - perhaps much older items caused problems but the modern punches are quite good. 50mm will take some winding in though. However they are expensive - one 50mm cutter would be more expensive than the full kit of hole saws indicated by Stuart. As Neil stated use a peice of ply as backing - this will stabilise the pilot and stop the saw teeth from juddering. When using an electric drill ensure you are holding on tight in case it snatches. Roger Quote Link to post Share on other sites
stuart Posted January 14, 2011 Report Share Posted January 14, 2011 I havent had any problems with the Bosch cutters and that set up with the quick change pilot drill will take out a steering column sized hole with no wandering or snatching just straight through 18SWG and ejects the circle cut out with no drama. (If you`re doing left to right conversions the circle removed is perfect to weld back in the other side ) Stuart. Quote Link to post Share on other sites
TomMull Posted January 15, 2011 Report Share Posted January 15, 2011 Yep and clamp a piece of wood behind Don't forget the cutting lube. I like wax (like Lennox lube tube) better than oil; no mess. Tom Quote Link to post Share on other sites
AndrewMAshton Posted January 15, 2011 Author Report Share Posted January 15, 2011 Hello, thanks for the excellent advice, I will be doing the job in a couple of weeks so will post some before and after pictures, and using a piece of ply and cutting lube!! Andrew Quote Link to post Share on other sites
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