GeoffT
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| posted on 6/1/09 at 09:27 PM |
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Making a simple round 30mm hole in 6mm steel plate.
In my many years of amateur engineering and bodgery I've learnt ways to DIY most tasks, but the one that's always defeated me is cutting
large holes in steel plate.
Once again the spectre of chain drilling and filing has come back to haunt me - I need a 30mm hole in a piece of 6mm plate. There must be a way that
doesn't involve :-
a) a lathe,
b) some other hugely expensive tool,
c) taking it to some bloke somewhere.
.......so if you've found a nice, easy DIY way of doing this - I'm all ears
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mr henderson
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| posted on 6/1/09 at 09:29 PM |
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Hole saw in an electric drill, can produce surprisinlgy accurate results
John
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Miks15
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| posted on 6/1/09 at 09:29 PM |
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30mm drillbit?
Id just go for drilling loads of holes around the circumferce and filing it back
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tomgregory2000
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| posted on 6/1/09 at 09:30 PM |
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second on hole saw (good quality for 6mm plate) and cutting fluid and lots of time 
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BenB
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| posted on 6/1/09 at 09:33 PM |
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6mm plate + hole saw= worlds shortest lived drill bit...
Been there, got the t-shirt etc etc etc....
Maybe if it's made from unobtanium!!!
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rayward
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| posted on 6/1/09 at 09:34 PM |
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i've done 6mm stainless with a starret cutter and loads of cutting fluid,
hth
Ray
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balidey
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| posted on 6/1/09 at 09:36 PM |
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My work drill holes of similar size through that sort of thickness many times a day. Hole saw everytime.
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daniel mason
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| posted on 6/1/09 at 09:40 PM |
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defo hole saw! Am an electrician and we use them all the time with great results, as long as you have a decent drill. if you dont fancy drilling a 30
mm hole you could always drill a slightly smaller one and widen it with a cone cutter!
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Mal
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| posted on 6/1/09 at 09:44 PM |
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I wanted a close clearance fit in 10mm plate for a 30mm diameter bar and found that a 29mm dia hole saw (a standard size) made a suitably oversize
hole for the 30mm bar. A bench drilling machine on a slowish speed is good for this.
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coozer
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| posted on 6/1/09 at 09:45 PM |
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Hole saw eh? I've bought a couple, absolutely w**k at cutting holes in metal, fine in fibreglass.
Are they any better in a pillar drill ie?
1972 V8 Jago
1980 Z750
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nstrug
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| posted on 6/1/09 at 09:47 PM |
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Hole saw, preferably in a drill press. Use low speed (250rpm) and loads of cutting fluid. Remember to get cutting fluid on the centre bit as well as
the hole cutter, otherwise it will blunt.
Back off and let things cool down if/when it smokes.
Nick
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matt_claydon
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| posted on 6/1/09 at 09:56 PM |
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Anyone who's had bad results with holesaws in steel plate is either using cheap crap holesaws or going too fast and not using enough cutting
fluid.
Imagine the speed a saw blade moves when you use it by hand and aim for that sort of tooth speed, 100-200 rpm would be my choice.
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omega 24 v6
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| posted on 6/1/09 at 09:59 PM |
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hole saw will be fine on a slow speed torquey drill. or one of these if you've got the equipment for
it.rotobroach
If it looks wrong it probably is wrong.
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davidwag
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| posted on 6/1/09 at 09:59 PM |
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Hi,
Got a selection of Sandvik (now Bahco)hole saws, no problems cutting 38 mm holes in 10mm stainless steel to make manifold flanges, but as others have
said use a slow speed and lots of cutting fluid.
David
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mr henderson
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| posted on 6/1/09 at 10:00 PM |
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quote:
Originally posted by BenB
6mm plate + hole saw= worlds shortest lived drill bit...
Been there, got the t-shirt etc etc etc....
Maybe if it's made from unobtanium!!!
I've drilled plenty of holes in 3mm without problems. Maybe you are pushing too hard?
John
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GeoffT
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| posted on 6/1/09 at 10:03 PM |
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I'd given up on hole saws for cutting steel long ago, but several of you guys are obviously having success with it, so I'll have to
re-investigate these.
If you've got a link to any that you've tried, and will cut 6mm steel, I'd be gratefull..
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Schrodinger
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| posted on 6/1/09 at 10:05 PM |
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I would try getting a blacksmiths drill bit
http://www.lawson-his.co.uk/scripts/products.php?cat=Blacksmiths%20reduced%20shank%20drills
Has a 28mm bit but at £57 it isn't cheap
Keith
Aviemore
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wrigglypig
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| posted on 6/1/09 at 10:05 PM |
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What cutting fluid would you recommend??
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whitestu
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| posted on 6/1/09 at 10:06 PM |
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I've done several 35mm holes in 3mm steel with a hole saw and hand drill, but have got more accurate results with a smaller drill and round file
type hacksaw blade [can't remember what they are called].
Stu
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Antnicuk
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| posted on 6/1/09 at 10:12 PM |
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there is a vast difference in quality in hole saws. I bought a bosch set from screw fix for £25 for a about 10 saws in a nice box with 2 arbours,
after years of struggling with cheap ones, this set is brilliant.
Using a pillar drill makes life a lot easier and as said, slow speed with a little bit of oil, or just use a water squirty bottle to cool it.
Mu cousin is an engineer and uses thick stainless all the time. He has a hole saw set that was about £60 and that has been used loads.
The little black ones you see at the market are sh1te.
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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omega 24 v6
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| posted on 6/1/09 at 10:19 PM |
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We use starret at work. Very good and have drilled up to 6 inches in 3mm stainless steel before in a drill press.
One thing to bear in mind the minute it starts skidding your in trouble. It'll overheat and burn out very quickly. keep it slow and keep the
pressure on as well as the cutting fluid.
ETA these are the ones we useStarret
[Edited on 6/1/09 by omega 24 v6]
If it looks wrong it probably is wrong.
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stevebubs
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| posted on 6/1/09 at 10:35 PM |
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quote:
Originally posted by Antnicuk
there is a vast difference in quality in hole saws. I bought a bosch set from screw fix for £25 for a about 10 saws in a nice box with 2 arbours,
after years of struggling with cheap ones, this set is brilliant.
Using a pillar drill makes life a lot easier and as said, slow speed with a little bit of oil, or just use a water squirty bottle to cool it.
Mu cousin is an engineer and uses thick stainless all the time. He has a hole saw set that was about £60 and that has been used loads.
The little black ones you see at the market are sh1te.
Any model numbers? Might investigate the cost from work....
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dinosaurjuice
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| posted on 6/1/09 at 11:09 PM |
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i went through a stage of buying hacksaw blades at 33p for 12. i now buy 2 for £3 and havnt gashed my knuckles on a vice since.
in other words, you get what you pay for
you wont regret buying a selection of holesaws, very handy things.
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trikerneil
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| posted on 7/1/09 at 05:55 AM |
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I've just been using the bog stock Screwfix 32, 50 & 70 mm holesaws
LINKY in round and square tube and a bit of 6mm steel plate.
A pillar drill on it's slowest speed and cutting fluid is the way to go.
I used a mix of paraffin and engine oil as cutting fluid/coolant coz that's what I had.
HTH
Neil
ACE Cafe - Just say No.
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Fred W B
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| posted on 7/1/09 at 06:11 AM |
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As above, get a good holesaw from an engineering merchant - the yellow ones. I've done 80 mm holes in 5 mm stainless by hand with them before
(using an air drill so can run it very slowly, and the red cutting compound usually used for tapping)
Cheers
Fred W B
You can do it quickly. You can do it cheap. You can do it right. – Pick any two.
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