Drilling/cutting 4mm Steel

[binge]

I've mocked up a custom made, Highflow inlet manifold for my TZR engine.

It's basically a flat piece of steel, around 3" x 4".
4 holes drilled in it. One in each corner.

I've then got a curved piece of tubular steel, 30mm internal diameter.

I have cut one end off at a steep angle, So the lays almost flat, when stood on the Steel plate.
The other end is cut off square, as the carb will face up to this with a silicone coupling.



Now I need to cut a hole in the middle of this steel plate. It needs to be about 34mm wide, And about 50mm long. An elongated hole I guess.

I've had a shot at it with a hole saw, But have got nowhere really. It burnt the hole saw out.


Whats the best option?


I considered using the oxy/acc at work to blow it out, Starting from the middle.
It needs welding to the tubular steel, and grinding neat/flush after anyway.

However, I was afraid the heat transfer from the Oxy/Acc would warp the steel and make it quite un-flat. Giving a poor seal when bolting it to the engine.



Any help MUCH appreciated, as I am not a steel engineer.

[Tristan.]

Get a local engineering firm to do it on a milling machine. Or if you have access to a pillar drill, that + a large bit + lots of time.

[Pete.]

Fistly drill your four mounting holes in the plate.

50-34 = 16, so draw two center-lines that cross in the middle, and then mark-off 8mm either side of centre on the long line. Center-punch these points. Fix the plate using the mounting holes to some scrap timber/mdf/the dog and then spot the two center-punch marks with a small drill. Get a 34mm tank cutter (a.k.a hole saw, starrett cutter) and drill a mm at a time swapping between the two holes so you are describing two over-lapping circles. Swap between them until one breaks though then remove that disc and drill the other using the hole in the timber beyond as a guide. Use a half-round file to tidy the job up.

If you are burning out hole saws then you have a hole saw for drilling timber or you are turning it too fast. Use water or oil for coolant/lube.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Walloper]

What 'Steel'?
Stainless will eat any hole saw unless you let yer Gran do it.
Tunza lube and no heavy feed or fast speed.

Or you could use a small diameter bit and make hundreds of wee holes around the inside of the circle you want the half round b4stard file to clean up.
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W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[effit]

Use a mag drill with a 34mm cutter, any Fab shop will have one and shouldnt cost you a lot of dosh to have it done. The ones Ive used are Evolution but I think Rothenberger and a few other types are out there. Even have a look and see if you can hire one for a couple of hours at a local tool shop.
The shop will probably ram you for the cost of the drill bit so have a looky on Egay or somewhere like that.

here is one similar to what i`m talking about...

https://www.evolutionpowertools.co.uk/us/evolution_me3500.html

[stinkwheel]

I agree with Tristan.. A milling machine is the weapon of choice for this task.

If you take it in already marked out, they might even do it for a six pack of beer during their lunch break.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[jimspeed]

if you are anywhere near ludlow i have a huge milling machine here and i would be willing to give it a go for you one eve..
i would mill it after welding too so the plate is flat again unless you were thinking of brazing it
jim
edit just seen you are in kent so a bit far i would av thought lol
____________________
Hyosung cruise 125(passed test on, sold) Kawasaki el 252 (better than expected but sold on) Kawasaki GPZ500S first "big"bike.(sold) ZZR600 E5..Z750 2007,ER5, currently on a 2008 Enfield bullet electra x and loving it..
,"Alpha-9: Is there any correlation between dyno rod and dyno kits?"

[Walloper]

[jimspeed]

na and its a bit big to post..
____________________
Hyosung cruise 125(passed test on, sold) Kawasaki el 252 (better than expected but sold on) Kawasaki GPZ500S first "big"bike.(sold) ZZR600 E5..Z750 2007,ER5, currently on a 2008 Enfield bullet electra x and loving it..
,"Alpha-9: Is there any correlation between dyno rod and dyno kits?"

[binge]

Brazing it was going to be my weapon of choice as that's all I have access to. And I'm also pretty good at brazing, I've made up complete exhaust systems with the gas axe.


Pete, You're the man! Will give that a go tomorrow with a fresh hole saw. Will have to check what ones I've got.

Failing that, I'll have to nip round a few places and see if an engineering firm can help me out.


It's just regular mild steel I beleive. I've used it to make my engine mounts out of. Certainly not stainless because a piece I used for a reg bracket, That I didnt paint, Has rusted slightly.




Ben

[stinkwheel]

Alloy would be far easier to machine and lighter. Much more difficult to join though.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[binge]

Alloy also stores heat. I made the 2 pieces out of alloy a while back. Never did get them joined up though.




Ben

[stinkwheel]

[BanditsHigh]

Just use a jigsaw with a metal cutting blade ... I made some suspension linkages out of 6mm stainless steel and although it took a while it worked out ok ... 4mm steel will be a breeze

[Walloper]

Alloy (Aluminimuminum) will conduct heat and electricity quite easily and better than steel.
____________________
W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[Pete.]

You can drill stainles with a hole saw no problem, you use low speed and high pressure (and coolant). Some stainless steels work-harden very quickly if you don't use enough pressure. I drilled four 38mm holes in 6mm thick 316 stainless with one drill and it still had all it's teeth.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[stinkwheel]

[Blau Zedong]

Water jet would be quickest if there are any profiling guys near you.
____________________
18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[Walloper]

Thermal Conductivity

Steel, Carbon 17 - 43 (app)
Stainless Steel 16

Aluminium 118 -144
Copper 204 - 233
Silver 248 (best)
Gold 182
Platinum 42

Generally, a material's electrical conductivity is almost equal to it's thermal conductivity.

Stinkers, have you tried putting a bar of Aluminumimnun and one of Steel in a fire to find out which one you drop first?
____________________
W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[DrDonnyBrago]

Oooh I thought thermal conductivity was at least partly dependent on the density of the material...

Learn something new everyday eh

[stinkwheel]

[Pete.]

What an excellent line to drop into a conversation "Back when I did fire-eating"

Yes, that would be the reason - the heat was radiating off the aluminium rod. The denser steel rod would store more heat and radiate it less quickly.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Walloper]

Does that fire-eating not lead to heart-burn and Charring of the Underpants?
____________________
W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair