thingmaker3

Ok im new to this and not the most knowledgeable on electronics but a friend who is is helping me, I have seen a design online for a 3 to 10kw unit but it gives lots of options and maths.

 

I heat a lot of 1/2" ( 12mm ) round and square for regular items I make so was looking at making it just for that.

 

skin effect! have read that low frequencies for deep heating and higher for heating the surface, as im only doing 1/2" thick what do you thing the best frequency to aim for is?

 

how much power! will 3kw be enough or should I look at more?

 

here in the UK we have 240 volt single phase mains.

 

was thinking of an addition in the form of a timer for heat time, do you think this is a good idea?

 

reheat time will probably be a lot shorter than first heat and will it also be quicker if reheating something I have drawn out thinner.

I'm getting my numbers from Elements of Indution Heating Design, Control, and Applications by Zinn & Semantin.

For a 1/2" round bar, you'll want about 30kHz minimum.

Power calculations get complex, but you should be able to heat 6" of your 1/2" round to forging temperature in a little more than four minutes with 3kW. If you've got a good close coil. Maybe less if you wrap it in thermal insulation.

That's probably not what you wanted to hear, but physics is physics. Your rule of thumb here is 400 watt-hours per kilogram, assuming minimal losses to the atmosphere.

A 15kW machine will work quite well, and the commercial ones adjust their frequency automatically.

You'll find part of your formula in the back of Palmer and Luerssen's Tool Steel Simplified. Remember, the formulae only get you into the ballpark. You have to find the pitcher's mound on your own by experimentation. ;)

Put your stock in it and use the matching "wrench" to shear off bar?

My wife sat in the thing at a sci-fi convention last year. It's resin, just like Mr. P sez.

It's not a "junk pile," it's a "supply depot." :)

High? How high is a wall? How high is a fence?

"Priced high" compared to WHAT exactly?

Why not just say you choose not to go?

Variances in the local magnetic field can change radically based on where you parked your truck and where your quench tank is in relation to your anvil. These must, of course, be taken into account when pointing the to-be-quenched blade. :D

I am a hobby blacksmith. I've already sent in pay for the whole weekend. I'm very much looking forward to this event!

One can buy a whole pound of powdered iron for that price and mix up a lifetime supply of flux.

Sparex #2 is mostly sodium bisulphate, yes. But Sparex #2 is not for ferrous metal, it's for things like copper or silver.

You could use it as a clip-on earring for that giant statue you were going to make...

The selenium is for improved machinability. Second hit on Google sez so. Also says it might have tellurium or sulfur instead of selenium. So it might be hot short. I would definitely experiment prior to spending much money. ;)

If it's a plow, why not use plow steel? :lol:  

He insists that good tempered steel will have smaller carbon nanotubes or something.

I'll go with the "something." Good tempered steel will have smaller grains (crystals.) Carbon nanotubes are for carbon nanotoothpaste. Just brush 'em off!

If there is any means of attaching gears to the far side, I would guess "pasta maker."

double post

I really wouldn't worry about stress concentration in this instance. Have a look: http://courses.washington.edu/me354a/chap6.pdf

Sure, it'll take more to break something at an etched logo than a stamped one, but who here has ever seen a knife fail there? (As opposed to just repeating tales?)

Stress concentration is much more of an issue at the shoulder of the tang, as one can understand by reading the reference given.

I found an MSDS for Boraxo. One of the ingredients listed is "sodium soap." I don't know if that means "lye soap" or something else.

Ric, according to a couple works I've read on spring making, you can use 35% to 52% of the UTS for estimating torsional yield strength.

And THANK YOU for posting this chart! I've been looking all over the web for something of that nature.

I made a cold-use centerpunch on my lathe, and I made a cold-cut using the lathe, a bandsaw, and disk sander. AND I HAD FUN DOING IT. :P  :P :P  :P  

I have no problem viewing it. Must be a facebroke user settings thing...

Eating a little rust ain't gonna hurt you. Eating a little gluten or a little sugar won't hurt you either. Just keep it to a minimum.

As Thomas says, just have folk treat it like cast iron cookware. Or use stainless.

You'll find three or four stout legs will serve you better than six spindly ones.

Did you include an ash-dump mechanism?

Geronimo Bayard used to call the dominant hand the "dumb" hand (even a dummy could use it) and the non-dominant hand the "smart" hand (have to be smart with it.)

What is the purpose of the knife? A fillet knife needs to be thinner than a machete. A bowie should be thicker than a scalpel. Whatcha makin?