LBMEFM
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| posted on 7/1/09 at 08:15 AM |
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Use a local engineering firm - much easier and accurate.
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Mr Whippy
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| posted on 7/1/09 at 08:25 AM |
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I use a good quality stepped cone cutter, faster than a hole saw on steel and it always leaves a nice edge. I have a set like these, tbh their a must
really for working on cars and the holes they cut are more accurate size wise than can be done with a drill bit as they don’t vibrate when cutting. So
fast on GRP that you need to watch how hard you press  but also can leave a nice chamfer through the gel coat at the same time to prevent cracks
forming, very handy
[Edited on 7/1/09 by Mr Whippy]
Fame is when your old car is plastered all over the internet
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londonsean69
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| posted on 7/1/09 at 08:50 AM |
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Problem with using stepped holesaws on 6mm plate, is the steps might not be 6mm, if they are less the top of the hole would be wider than the
bottom.
Easy to overcome by filpping the work over though.
Use a holesaw, but make sure it is the solid type that goes onto a threaded arbor, rather than the poo flexible metal ones where several can slot
into the base plate for storage.
My only problem is my pillar drill only goes down to 450rpm, so am limited in the size I can cut (although my cordless is fully variable)
I drilled a load of 38mm holes in 3mm plate on Saturday and the screwfix own brand holesaws did fine.
Sean
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tonym
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| posted on 7/1/09 at 09:42 AM |
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30mm hole
What you need is A Practool super drill.
It will drill any size hole from 1/2" to2" in steel wood or ally. I have had one for 10 years and it is a super bit of kit. It will cost
less than 1 large drill and drill any hole you will ever need.
Check the website practool.com
They are made in Australia but avaliable in the U.K.
For info tel. 01944 240978
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MikeRJ
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| posted on 7/1/09 at 09:42 AM |
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Cheap hole saws are scrap within seconds of going near steel IME, they are a waste of money unless you want them only for wood or plastic.
A decent quality bi-metal hole saw will easily go through 6mm of mild steel with no problems provided you drill slowly enough and use cutting fluid,
but then again they aren't particularly cheap.
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theconrodkid
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| posted on 7/1/09 at 10:50 AM |
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how,s about cutting a square hole in the plate with an angry grinder and making a 3mm plate with said hole to fit over the square hole? 3mm will be
strong enough for the master cylinder mounting
who cares who wins
pass the pork pies
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owelly
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| posted on 7/1/09 at 10:50 AM |
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I use Starrett for metal and those cheapy rubbish ones for fibreglass. The FG seems to take the cutting edge off the saws so I'd rather fudge a
cheap one!
I have cut many holes through lots of thicknesses of steel from 1mm up to 10mm floor plates. Drill press is best but a good, slow hand held drill will
work. If you need an accurate sized hole, drill the hole through a piece of 12mm plywood and clamp it to your steel. It stops the blade from wandering
about!
I use Rocol Cutting paste. It's like grease. If it starts to smoke, your getting too hot. Stop, let things cool down and start again. If the
metal turns blue, you've already hardend the steel so when it's cool again, go very careful, slowly and with plenty of cutting paste! Make
sure the cutter is cutting and not rubbing it's way through! If it starts to rub, stop, check your teeth(!) and let things cool! When the device
is cutting correctly, the material that is being removed (swarf) carries heat away from the cutting edges so aim to keep them cutting!
Good luck.
http://www.ppcmag.co.uk
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Davey D
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| posted on 7/1/09 at 11:12 AM |
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I use the Bosch "Progressor" hole saws. They arent cheap, but them havent let me down on any job yet. They are quick release changeable
too. here is a link to somewhere that sells a good range:
http://www.axminster.co.uk/product-Bosch-Bosch-Progressor-Holesaws-19863.htm
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02GF74
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| posted on 7/1/09 at 11:37 AM |
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didn't someone say recently that once the drill has done its job, replace it with a steel rod to prevent the hole from wandering?
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britishtrident
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| posted on 7/1/09 at 01:31 PM |
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quote:
Originally posted by 02GF74
didn't someone say recently that once the drill has done its job, replace it with a steel rod to prevent the hole from wandering?
I have done that in the past especially good for soft and sheet materials but in a lot of hole saws a simple steel rod wouldn't work.
I have cut several 50+mm dia holes in 3mm steel without problem using a B&Q hole saw (one of the orange ones -- Performance Power brand I think)
--- pillar drill at slow speed, with soapy water as cuttting fluid (nb use liquid hand soap not washing up liquid).
Because the cutter will wander slightly you need to buy a hole saw slightly smaller than the final size.
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Peteff
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| posted on 7/1/09 at 02:14 PM |
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I've used my Aldi bimetal cutters to cut 4mm mild steel with some 3 in 1 type oil applied while it was cutting and it went through no trouble
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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GeoffT
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| posted on 7/1/09 at 05:14 PM |
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Just to update, went to see Mr Screwfix today and treated myself to an Ebauer cobalt holesaw of the requisite size.
My hole is now cut,  it took about 10 mins with my DIY setup of a crappy old drill and stand, and I quickly found out that, as mentioned by many
people, slow speed big torque is what you need, and what I didn't have.
Anyway, after about 10 mins I was through (I never realised that 6mm was such a long way...) but gave the cutter some abuse TBH in the process - you
definitely need a good pillar drill for this. Hats off to Ebauer cobalt holesaws though, it felt as sharp after it's ordeal as it did at the
start.
Glad to see you chaps have a healthy interest in a nicely engineered hole though, thanks for all the input
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JoelP
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| posted on 8/1/09 at 09:08 PM |
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quote:
Originally posted by LBMEFM
Use a local engineering firm - much easier and accurate.
thats what caterham owners would do! This is LCB!
I used gearbox oil when i was last hole cutting, as the bottle had a good nozzle!
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PHULL
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| posted on 14/1/09 at 09:40 PM |
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Oxy torch?
go with the bi metal hole saws... when the stuff gets thick I chain drill round the perimeter and then use the hole saw. the chain drilling gives the
hole saw space for the chips to go.
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NS Dev
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| posted on 15/1/09 at 10:19 AM |
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agree on all the above, with the caveat that if you have a few to do, its not expensive to hire a rotabroach and the right cutter
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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