Jump to content
I Forge Iron
Sign in to follow this  
Tiefer

Firepot angles...

Recommended Posts

Ok...I'm a math flunky and I'm trying to build a new fire pot for my coal forge.  What I can't figure out is at what angle do I cut the sides so that I have a square or rectangular pot that fits together?!  There is probably an easy way to figure this, but is unbeknownst to me.  Could someone give a pointer or two? Is there a calculator for geometry dummies out there or do I have to use online pyramid equation/calculators (which still keep me lost).  I want to build a relatively standard firepot and I have 5'' by 1/4 plate.  I thought  13 or 14'' sides would be good and about a 4''ish base for a 3'' pipe.  Would love some help figuring this...Thanks!    

Share this post


Link to post
Share on other sites

Use cardboard and build a proto-type.

Adjust as needed to get what you want.

 

Take the adjusted cardboard proto-type to the metal cutting table and cut out your first pattern.

Weld it up and try it out. Tweek as needed and build a production forge.

Share this post


Link to post
Share on other sites

Thanks Glenn, good idea.  I started with that but thought there might be some 'generic' angles floating around to guide the way.  I think your right though, without a good lesson in compound angles it will be easier to eye ball it till I get there.  

Share this post


Link to post
Share on other sites

You're a math flunky and can't figure this out... Geometry man, geometry....

 

 

I did what Glen suggested, but in 1/2" plywood, not cardboard. 1st I figured out how deep I wanted the fire pot to be. 2nd I figured out how wide I wanted it to be less the center. In your example 14" less 4", so 10", and I divided that in 1/2. That gives you your A and B leg on the right triangle formed by the pieces. From that you can determine the hypotenuse. That would be how "tall the cut side is.

 

Then you draw a piece 14" wide with a perpendicular line in the center as long as the hypotenuse. At the top of this line, is the 4" perpendicular that forms the bottom.  Connect the dots and you have a pattern for a side. It sounds more complicated than it is if you draw it out.

 

 

I "cheated" and pulled my dimensions for sides and "height" off an existing commercial forge, so all I really had to do was work out the cut pattern.

Share this post


Link to post
Share on other sites

Well I wish I would have tried that... (and geometry is still very math like to me...but that makes a bit more sense).  I gave in to the old standard and fudged it.  Not pretty... not even close, but it works and much better than my old brake drum!  Almost like it's supposed to!  Next task is to figure the chimney.  Might do the standard design on that.  Thanks for the input, next time i will try the simplified version!

Share this post


Link to post
Share on other sites

Hmmmm maybe I misunderstood your 1st comment. By "flunky" I thought you meant "math nerd" and some of what you posted didn't make complete sense.

 

 

Nice thing about all of this is you can always make another. My forge is an ongoing project. This year it was a nice new forged set of legs. Next revision will be removable wheels and a handle so I can move the heavy beast this thing is becoming. Then there's tool racks, the clinker breaker to redesign.... I doubt it will ever be "finished".

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...