Metal Cutting Noob - how do i cut a hole?

[Picobrew]

I want to put a therm in my HLT kettle, so I got some weldless fittings. Now I need to cut a hole in the kettle. It is a super flimsy stainless kettle. What is the easiest technique? I don't have a dremel (yet), I just have a crappy drill.

Bonus question: This kettle has some cracks in the stainless at the top (on opposing sides, from bending or something). They are vertical cracks about an inch long on one side and 2 inches on the other that go to the top of the pot. Is there anything I can do to repair those cracks?

 

[GilaMinumBeer]

A crappy drill + good drill bit for stainless + a straight hand = hole.

 

[Picobrew]

A crappy drill + good drill bit for stainless + a straight hand = hole.

So do I just get like a 3/4" hole cutting bit or something? Does it need to be a certain material for the stainless?

 

[GilaMinumBeer]

So do I just get like a 3/4" hole cutting bit or something? Does it need to be a certain material for the stainless?

It helps to get a bit for stainless but is not "imperative". It simply reduces the potential for rusting.

Read the installation instruction for your fittings for the proper hole size. General rule is 1/16th larger than the nipple OD being used.

 

[Picobrew]

It helps to get a bit for stainless but is not "imperative". It simply reduces the potential for rusting.

Read the installation instruction for your fittings for the proper hole size. General rule is 1/16th larger than the nipple OD being used.

Thanks! Anyone have any thoughts on the "cracks" in my kettle?

 

[GilaMinumBeer]

Thanks! Anyone have any thoughts on the "cracks" in my kettle?

Find a welder and trade for homebrew.

 

[LooyvilleLarry]

ThreeTips:
1. GO SLOW. If you heat it up, it turns into the hardest stuff known to man.
2. USE Oil. See I 1. If it smokes, you need more oil
3. Use Pressure. A strong arm is good here.

I found that the step bits at Harbor Freight worked the best. I was surprised when the first hole only took a few minutes.

 

[Picobrew]

ThreeTips:
1. GO SLOW. If you heat it up, it turns into the hardest stuff known to man.
2. USE Oil. See I 1. If it smokes, you need more oil
3. Use Pressure. A strong arm is good here.

I found that the step bits at Harbor Freight worked the best. I was surprised when the first hole only took a few minutes.

What kind of oil would i use?? Apply it to the bit and the steel?

 

[Pintodave]

A step-bit would be your easiest solution... check out Harbor Freight, as Irr said, if you have one in your area or any hardware store... Dont forget to center punch the hole or drill a small pilot hole first to prevent the step bit from walking.

If you are going to use a drill-bit on a thin sheet metal-like product, use one with a 'flatter' angle across the top (wider split angle). Drill a hole in thin sheet metal and you will notice that drill bits dont actually drill perfectly round holes, they come out triangular in shape. Not very noticeable with a small hole, but the bigger you go with the diameter the more you notice it. Weird sounding I know, but true...

They make special cutting oils, but you can use whatever really... WD-40, 40wt motor oil, etc...

 

[Boodlemania]

Cutting fluid - I likes the Tap Magic. Works and readily available.

+ 1 on the step bit.
+1,000 on going slowly and using plenty of fluid.

 

[rbarr110]

A step-bit would be your easiest solution... check out Harbor Freight, as Irr said, if you have one in your area or any hardware store... Dont forget to center punch the hole or drill a small pilot hole first to prevent the step bit from walking.

If you are going to use a drill-bit on a thin sheet metal-like product, use one with a 'flatter' angle across the top (wider split angle). Drill a hole in thin sheet metal and you will notice that drill bits dont actually drill perfectly round holes, they come out triangular in shape. Not very noticeable with a small hole, but the bigger you go with the diameter the more you notice it. Weird sounding I know, but true...

They make special cutting oils, but you can use whatever really... WD-40, 40wt motor oil, etc...

When I drilled my keggles, I tried using a step bit from Harbor Freight. I destroyed the step bit cuttin one hole.... I needed to do 6. I ended up getting a hole saw for metal, not a real cheap one but not too bad. I think they were $10 (doesnt include the price of the mandrel and pilot bit) a piece and ended up using two to make the 6 1" holes.

 

[Pintodave]

That is the one thing about H.F... it's a crap shoot on the quality of their products... A high quality step bit from HD or Lowes will cost a bit more. You could always buy one cheap one from H.F. to practice with then upgrade to a higher quality step-bit if you have to do multiple holes...

As others said, go s l o w with your cutting speed. Anything with a high chromium and/or high nickel content is a beotch to work with... Inconel is another fun alloy that comes to mind...

 

[MNBugeater]

If you are looking for a 3/4" inch hole you might consider a local machine shop. They should have a steel punch. It will take them 15 seconds to stamp out your 3/4". Especially if you have more than one hole needed. Walk in with your kettle and 6 pack of homebrew and you'll find someone to do it.

I gave our local machine shop a case of beer and they stamped out 3 kettles, 2 holes each plus two in each lid in about 5 minutes.

 

[bendavanza]

I had good luck with the cheap HF step bits.
1) center punch
2) pre drill a small pilot with a regular bit.
3) use lube for cutting metal, wax stuff for band saws or thread cutting oil.
4) go SLOW and HARD, If you start going fast with the drill it will get dull and do NOTHING.

If you're doing it right, slow speed with lots of pressure, it will cut though each step pretty quickly. And you should be able to do multiple holes with one bit. If it's getting real hot, stop drilling and come back to it when it cools.

 

[Catt22]

A bi-metal hole saw is the best, but they are pricey. Probably too pricey for a one time use tool. The step bit would be the next best choice. Last resort would be a combination of a smaller drill bit and a cone shaped grinding stone bit for a drill. I've done it about every way you can think of and with care you can get good results with any of them.

Find a welder for the cracks. You might want to consider abandoning that pot for something better without that kind of damage. IOW, think about it before you invest much time and money in this one. Might be more trouble and cost than it's worth. A lot depends on your budget, determination and who you know (like a welder).

 

[Picobrew]

So I know some welders, but they have never even heard of "sanitary welding". They are HVAC and mechanic guys. Can they safely weld stuff for me?

 

[LooyvilleLarry]

You want a TIGger that has worked with stainless. Stainless flows different that just about anything except aluminum, which is also known to TIGgers.

You shouldn't have too much problem finding one. Craigslist worked for me.

 

[silvervan83]

I use a $10 hole saw from lowes and a spray can of PAM for cutting oil.

I have cut over 40 holes with the same bit and its still sharp. PAM works great cause it comes out of the can nice and cold and you can hold it in your left hand while you drill with the right. (or vice versa).

Oh, and I am using a 20 year old "skill" drill that is on its last leg.

 

[axr]

does the same drilling process apply for an aluminum kettle or is a different method required?

 

[Pintodave]

Alum. is way easier to work with. Take the same care to get a nice final product, but the cutting process itself will be easier. Take care not to get too crazy on the cutting pressure with the alum. since it is softer the bit might have a tendency to 'bite' into the material if you try to be a gorilla on it.

As far as "food grade welds", I was told it is this: it is flooding the inside of the container with the same cover gas (usually argon w/ TIG) as you are using on the weld. Because the containers are usually so thin, the heat will come through the back side of the work piece and when stainless gets hot (like molten hot) you will be exposing the regular steel to oxygen and then you could potentially end up with rust around that part of the weld even though its "stainless". Thus the use of the cover gas on the inside of the vessel and the outside part that you are welding. I am a machinist and not a certified welder, but thats how it was explained to me...

I'll let you know shortly on that part I am getting ready to weld some keggles up and just bought a y-block for my argon tank to flood argon to the inside of the keg. There is another product called "Solar Flux" that will do the same thing, but on their web site they recommend cleaning the area off after with a stainless wire-wheel for anything that will be used in beverage service, which could be a pain to do inside of a keg so I am going the cover gas route...

 

[gssmind]

I just used a dremel to cut 1/4 inch SS with no problem. However, you need to have a Diamond Bit for it to get the cut with no smoke and no oile.
They have two of them available at Home Depot:
1. $8 - Not a ture Diamond bit but it does the job but it will take you a bit longer to get the job done.
2. $40 - True Diamond bit and will definitely be faster and do the job.

I used the $8 one and there was no smoke or anything just had to make sure I ware my safety glass though.

 

[78kombi]

WD-40 literally stands for Water Displacement, 40th attempt. That's the name straight out of the lab book used by the chemist who developed WD-40 back in 1953. The chemist, Norm Larsen, was attempting to concoct a formula to prevent corrosion -- a task which is done by displacing water. Norm's persistence paid off when he perfected the formula on his 40th try...not a lubricant!!!! use cutting oil.

 

[Pintodave]

You shouldn't have stopped so soon on Wikipedia...


"Function

The long term active ingredient is a non-volatile, viscous oil which remains on the surface, providing lubrication and protection from moisture. This is diluted with a volatile hydrocarbon to give a low viscosity fluid which can be sprayed and thus get into crevices. The volatile hydrocarbon then evaporates, leaving the oil behind. A propellant (originally a low-molecular weight hydrocarbon, now carbon dioxide) provides gas pressure in the can to force the liquid through the spray nozzle, then itself diffuses away.

Formulation

WD-40's main ingredients, according to U.S. Material Safety Data Sheet information, are:
50%: Stoddard solvent (i.e., mineral spirits -- primarily hexane, somewhat similar to kerosene)
25%: Liquified petroleum gas (presumably as a propellant; carbon dioxide is now used instead to reduce WD-40's considerable flammability)
15+%: Mineral oil (light lubricating oil)
10-%: Inert ingredients"


It is not considered a "strong lubricant" but does contain oils and petrol products just the same. We arent building space shuttles.

But I digress..... The major theme in using some form of "lubricant" isnt necessarily for lubrication, but for heat dissipation. Go look at a CNC milling center with a 6" face mill removing a 1/4" of hardened steel per pass. They are flooded with coolants that do contain thin oils (water soluble), but the main concern is keeping the tool and the work piece cool. Heat is what kills tooling. You could flood it with H2O and it would be better than doing it dry. For doing light finish cuts on Alum, WD-40 works awsome, it keeps the chips from smearing and dragging on the piece giving you a better finish.

 

[bendavanza]

BTW the WD in a can is better than the spray stuff. Yes it's got some lube in there but you'd probably be better off using something else made for cutting metal.

 

[MrShake]

I always use 3-in-1 oil for lubing my step bits... never had a problem!