Drilling thermopots

[djcorbetto]

I'm trying to drill a thermopot and I got a set of bits for metal and it's just not drilling through it and it's not making a dent infact I broke drill bit

 

[mojonojo]

I'm trying to drill a thermopot and I got a set of bits for metal and it's just not drilling through it and it's not making a dent infact I broke drill bit

its stainless - use a hardened drill bit, lots of oil and slow drill speed. take it easy otherwise you will work harden the stainless and it will be difficult to cut.

 

[morethanworts]

Qmax cutters sound like they're the answer, rather than wrecking a pot. I have yet to try.

 

[djcorbetto]

I have a qmax cutter but I need the pilot home first

 

[joe1002]

I'm trying to drill a thermopot and I got a set of bits for metal and it's just not drilling through it and it's not making a dent infact I broke drill bit

its stainless - use a hardened drill bit, lots of oil and slow drill speed. take it easy otherwise you will work harden the stainless and it will be difficult to cut.

+1 although I didn't use oil.

 

[djcorbetto]

http://m.wilko.com/wilko/product/detail ... Id=0289369 I have these drill bits

 

[Jay7792]

http://m.wilko.com/wilko/product/detail.do?categoryId=&itemId=0289369 I have these drill bits

Yep, I use them to!

Jay

 

[AndyBWood]

Hi djcorbetto,

I used cobalt drills to get through the steel. Started small as a pilot and then went in with the bigger one; from memory I think it was about a 12mm hole that was needed for the 20mm and 40mm Q-Max cutters.

The drill bits where bought for purpose so brand new when used but still took some time to cut through; that thin pot wall is tougher than it looks.

The Q-Max where a revelation. I just didn't think they'd work by tightening a bolt up but they popped a perfect hole in seconds.

Good luck with the build.

A

 

[Pakman]

From my recent experience drilling into my boiler :-

Make sure you use a dot punch (or nail) and hammer first to make an indentation in the surface of the metal. This stops the drill bit skidding around.

Then drill a hole using the smallest bit you have, usually 2mm or similar.

Then open up hole gradually by using larger bits in order.

A bit of hassle but worth it in the long run if you want to retain all your drill bits in one piece and a nice clean edge to the hole.

I have a set of three stepped panel cutters like these http://www.screwfix.com/p/exact-spiral-flute-step-drill-bit-6-36mm/63656 which work very well and allow you to clean up the hole from the inside once done. :thumb:

Graham

 

[AndyW]

I have found one of these very good for cutting the pilot holes for Q-Max cutters. I was cutting
1.2mm stainless. I must have done 40+ holes with it and it is still fine.

http://www.ebay.co.uk/itm/Irwin-Ste...Home_Garden_PowerTools_SM&hash=item589c707625

The step sizes are small and open out the initial 2mm pilot hole very easily.
Also less than £5 including postage.

 

[djcorbetto]

I have found one of these very good for cutting the pilot holes for Q-Max cutters. I was cutting
1.2mm stainless. I must have done 40+ holes with it and it is still fine.

http://www.ebay.co.uk/itm/Irwin-Ste...Home_Garden_PowerTools_SM&hash=item589c707625

The step sizes are small and open out the initial 2mm pilot hole very easily.
Also less than £5 including postage.

Those look good, do they make it quicker to drill?

 

[FuzzySteve]

On my recent thermopot job, I used a Starrett cutter bought from Screwfix. I had used cobalt bits in stainless before, and the arbour on the Starrett blitzed the stainless just like it. The hole saw wasn't shoddy either. Recommended certainly, although I'm not sure they'd have the longevity of a Qmax cutter.

 

[djcorbetto]

Starret cutter sounds like a good idea. I will do some research

 

[joker]

i've used both q max and starrett hole cutters and both have performed well on the bergland stainless steel pots. the time
consuming task for me was drilling the pilot hole using a cobalt drill. i eventually found the best way to get through the pot was to use
a 3mm tile / glass drill (spade end type). it's then fairly easy to open the hole up using the pilot drill.

 

[Fil]

The problem i had when first drilling a hole in my Shiney pots was i had read and heard about this work hardening, and on the odd occasion used a drill in metal before i had overheated it SO.. I went to silly extremes with the trigger control on my battery drill and drilled so slow i could almost count the revs as it span. it took ages.....

Then i needed to drill a hole and had lent my drill and bts out.. so i picked up the 450w? mains drill, and to compensate for not having the fine trigger control decided to pulse the trigger a single pulse at a time.

I also sprayed the bit and spot to drill with a squirt of wd40, using a bog standard 3mm bit it was thru with a single less than one second pulse..

to go thru the dbl skin of a thermopot lid i used a tungstun coated stepper drill bit

(pulse n squirt with wd40.. and dont be tempted to drill with one hand and squirt with the other... when the step dril bites hehe)

tho brace the work peice for the larger cuts as when it bites if you dont have it stable it will easily escape your grip

if you can puncture the skin with a point (nail/screw, cross head jewlers screwdriver) opening it up further is a doddle compared to drilling the hole, but be mindful of denting a pot with a huge hamma and if going thru a stockpot wall an internal brace to ward off a dent is a good idea

proper oils would work better than wd40, but even with 1 sec pulses and a squirt inbetween its a much faster job than drilling slowly with a fine control battery drill.

 

[djcorbetto]

Thanks a lot for that, I have been very tempted by the idea of a sharp nail and hammering it through the skin but my fear is exactly what you say which is the dent that it will leave, I own a qmax cutter but what if the dent is bigger than the hole would be?

That step cutter what kind of price did you pay for it? The ones I've seen on eBay are cheap compared to ones in shops like screwfix etc

I think I will just go ahead and try the nail approach, what's the worse that can happen....

 

[Fil]

its a cheap ebay (circa £7 for 3 sizes set, 4-10mm 4-16?mm an 4-28mm? iirc)

if used for longer than a single <1sec pulses u will burn off the yellow (Tungsten?) plate i have burnt out all 3 of mine now during my own learning experience..

and a file is needed to clean the sharp hole burrs left, its not the clean cut of the qmax..

Yes bang it with a sharp to puncture the skin, the thermopots are thinner skinned than the stockpots, and the insulation supports the skins. i used a jewlers cross head screwdriver.. it wont take much to puncture a thermopot skin.

the tape helps stop the drill from wandering

if going thru the bottom skin for a drain, an angle grinder can be used to cut out a channel, not as pretty as a hole but a big hole will take time and more tools to cut, and when sat upright u cant see the hole cut..

 

[LeithR]

When I cut my holes for Thermometer and Sight Tube I packed my boiler with wood so the hole site was supported from within the boiler. I found this worked well for me.

 

[oldjiver]

I remember working as a fitter cutting 1/4 inch stainless steel small machine parts (100s of them) with a bandsaw and trimming with a file. What a nightmare!! Hard stuff to work with.

 

[Aleman]

I used a small boy to squirt the work area with a stream of water, as I drilled the pilot hole. Lots of pressure with cobalt bits and working the bit slightly from side to side to help it bite.

I've used Bosch Cobalt hole saws and they work fine but blunt after 3 or 4 holes. The larger diameter ones (like 64mm for Immersion elements) blunt really quickly unless cooled.

I'd probably invest in Starret Cutters next time. . . .although for a single skin hole you can't beat a q max punch