Author Topic: Banjo Build  (Read 153930 times)

Offline S. Heslop

  • Hero Member
  • *****
  • Posts: 1154
  • Country: gb
  • Newcastle Upon Tyne
Re: Banjo Build
« Reply #150 on: June 12, 2015, 12:29:59 PM »
Tried the HSS again. Got about 4 teeth into it before the tip broke off. Perhaps it is just the steel I was trying to harden for the punches. I guess i'll find out when that rebar arrives!

Offline vtsteam

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6466
  • Country: us
  • Republic of Vermont
Re: Banjo Build
« Reply #151 on: June 12, 2015, 01:40:12 PM »
I still think a cold chisel is the way to go, don't you have one kicking around in the rust and odd bolts, shot VW Beetle condensers, and half bent cotter pins at the bottom of your tool box? Everybody else does.  :lol:
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline vtsteam

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6466
  • Country: us
  • Republic of Vermont
Re: Banjo Build
« Reply #152 on: June 12, 2015, 08:09:24 PM »
This one was kinda interesting:

Quote
To anneal a small piece of tool steel you may need to bury it with a larger piece of steel heated much hotter (an orange). Bury the two pieces next to each other but not quite touching. Test as above. Remember, the 40°F (22°C) per hour is a maximum rate, the slower the anneal the softer the steel (to a point).
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline chipenter

  • Hero Member
  • *****
  • Posts: 909
  • Country: gb
Re: Banjo Build
« Reply #153 on: June 13, 2015, 02:57:20 AM »
Have you tried another file as a chisel just let the colors down to dark straw , no need the anneel and reharden .
Jeff

Offline S. Heslop

  • Hero Member
  • *****
  • Posts: 1154
  • Country: gb
  • Newcastle Upon Tyne
Re: Banjo Build
« Reply #154 on: June 13, 2015, 12:09:09 PM »
Have you tried another file as a chisel just let the colors down to dark straw , no need the anneel and reharden .

I feel that files are too thin.

I remembered that I have a whole bunch of empty fire extinguishers that'd probably make good holders for the charcoal. Not sure how important insulation is though. I imagine I'll be getting the files hot outside of the fire first.

Offline S. Heslop

  • Hero Member
  • *****
  • Posts: 1154
  • Country: gb
  • Newcastle Upon Tyne
Re: Banjo Build
« Reply #155 on: June 14, 2015, 12:42:41 PM »
Take three.


It got pretty hot inside. I'm a little worried the files might've melted.


Kept topping it up with charcoal. This big rasp is too tall for this really, i'm worried that the exposed end might conduct the heat out too fast. I had the whole thing glowing but after switching it off I compacted the charcoal down a bit and the end was already cool.

Anyways, it won't be till tomorrow till I can see how it worked. It at least seems to be cooling slower than with the other methods.

Offline S. Heslop

  • Hero Member
  • *****
  • Posts: 1154
  • Country: gb
  • Newcastle Upon Tyne
Re: Banjo Build
« Reply #156 on: June 14, 2015, 04:47:37 PM »
Decided to pull the big rasp out, and the others came out with it. They've melted and fused together!

Might be the end of the rasp adventure. I suppose i'll see how well they softened tomorrow.

Offline vtsteam

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6466
  • Country: us
  • Republic of Vermont
Re: Banjo Build
« Reply #157 on: June 14, 2015, 05:11:20 PM »
Gee, I spend half a summer trying to build a charcoal burning iron melting sawed of cupola, which doesn't work, and you just stuff some charcoal in an old fire extinguisher and melt alloy steel with it!  :doh:

 :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:


No refractory or nuttin....!
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline S. Heslop

  • Hero Member
  • *****
  • Posts: 1154
  • Country: gb
  • Newcastle Upon Tyne
Re: Banjo Build
« Reply #158 on: June 14, 2015, 06:21:29 PM »
Gee, I spend half a summer trying to build a charcoal burning iron melting sawed of cupola, which doesn't work, and you just stuff some charcoal in an old fire extinguisher and melt alloy steel with it!  :doh:

 :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:


No refractory or nuttin....!

I figure it won't last long till the thing burns through though. I'm interested to see how eroded the inside is after dumping the ashes out (into another fire extinguisher. Might as well hold onto them).

Offline vtsteam

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6466
  • Country: us
  • Republic of Vermont
Re: Banjo Build
« Reply #159 on: June 14, 2015, 07:15:55 PM »
Simon, I think natural draft might have worked better.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline vtsteam

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6466
  • Country: us
  • Republic of Vermont
Re: Banjo Build
« Reply #160 on: June 14, 2015, 07:24:59 PM »
Check the image in this post, it's from Andrew Weyger's Blacksmithing books. It shows a natural draft forge made from a can and stovepipe. I don't personally think that much stovepipe is necessary -- probably a couple feet would do. In fact another fire extinguisher, maybe.

http://www.iforgeiron.com/topic/29696-my-better-bellow/?do=findComment&comment=304844
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 8966
  • Country: gb
  • East Sussex, UK
Re: Banjo Build
« Reply #161 on: June 15, 2015, 02:48:36 AM »
That illustration of the hanging forge looks like an excellent way to set fire to a tree  :bugeye:
Andrew Mawson
East Sussex

Offline S. Heslop

  • Hero Member
  • *****
  • Posts: 1154
  • Country: gb
  • Newcastle Upon Tyne
Re: Banjo Build
« Reply #162 on: June 15, 2015, 05:05:30 AM »
Simon, I think natural draft might have worked better.

I think having a more controllable blower would've helped. I had the outlet of a vacuum cleaner and tried a few crude ways of adjusting the air but none of them worked. Plus I started to get concerned about the top layer of charcoal not igniting, and so I was going full blast to try get the air to reach the top as well.

I did also think about removing the files and then putting them back in when it got hot, but to get the files in they had to be hammered down, which I wasn't so excited about doing over the hot coals.

Offline vtsteam

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6466
  • Country: us
  • Republic of Vermont
Re: Banjo Build
« Reply #163 on: June 15, 2015, 08:39:34 AM »
Simon if you happen to need to control a blast in a simple fashion without a normal diverter, you can just have short pipe on the blower separated from a longer pipe in the tuyere. You just alter the distance between the two, and the aim between them until your furnace is running at the rate you want. A few bricks can hold the pipes in position.

Andrew, I'm sure Mr. Weygers was careful not to burn down his tree. The devil is in the details, as in most things having to do with fire, Including bonfires, campfires, etc. His books are blacksmithing classics, and I admire them greatly.

I can hold my hand two feet above the 2' length of stovepipe I set on my current melting furnace comfortably, and that is while melting metal with a blower, not just forging small parts in a tin can forge with an atmospheric draft.

A longer pipe suspended well below a limb on a small atmospheric forge as shown will run quite cool. Most anything we do can be dangerous if approached without awareness. Running a blown exhaust direct into pine needles during a drought wouldn't be advisable, but I think most people wouldn't do that. I wouldn't even run my iron furnace in the clear under drought conditions. Even running a hand grinder can be danerous then. An illustration of what the author found useful does not absolve people from using good sense when doing the same.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline S. Heslop

  • Hero Member
  • *****
  • Posts: 1154
  • Country: gb
  • Newcastle Upon Tyne
Re: Banjo Build
« Reply #164 on: June 15, 2015, 09:14:55 AM »
Simon if you happen to need to control a blast in a simple fashion without a normal diverter, you can just have short pipe on the blower separated from a longer pipe in the tuyere. You just alter the distance between the two, and the aim between them until your furnace is running at the rate you want. A few bricks can hold the pipes in position.

I was actually trying something similar to that, by angling the vacuum cleaner nozzle on the end of the pipe going into the extinguisher. Sort of balancing it at an angle so it wasn't throwing all the air in. But like I said I decided to go for full blast to try get the charcoal on top burning.

But yeah I think i'm done with this rasp stuff now. I'd have to find some more old files to continue it for starters.

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 8966
  • Country: gb
  • East Sussex, UK
Re: Banjo Build
« Reply #165 on: June 15, 2015, 09:36:47 AM »

Andrew, I'm sure Mr. Weygers was careful not to burn down his tree. The devil is in the details, as in most things having to do with fire, Including bonfires, campfires, etc. His books are blacksmithing classics, and I admire them greatly.



Steve,

A previous owner of our place, when doing some building works, decided to burn rubbish too close to the base of a rather nice (at least 200) year old Yew tree. So looking from the field towards the house you saw a lovely tree, but from the house side all the branches were scarred, black,  and dead. It did at least salve my conscience when it had to come down to make way for an extension.

Ironically he is a retired member of the London Fire Brigade  :lol:
Andrew Mawson
East Sussex

Offline vtsteam

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6466
  • Country: us
  • Republic of Vermont
Re: Banjo Build
« Reply #166 on: June 15, 2015, 10:00:37 AM »
Andrew my former neighbor was head of the fire department here. He and  the department were burning some grass off of his field opposite as practice and it got out of control. Managed to get it out just before it jumped the road to my property!

It's kinda like how most psychiatrists are in their personal lives nutcases....  :lol:
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline S. Heslop

  • Hero Member
  • *****
  • Posts: 1154
  • Country: gb
  • Newcastle Upon Tyne
Re: Banjo Build
« Reply #167 on: June 15, 2015, 03:43:14 PM »
Hey that rebar arrived today. Thanks again for sending it.

Just a shame that I don't really need it for the rasps any more. Either way i'll find a use for it eventually.

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 8966
  • Country: gb
  • East Sussex, UK
Re: Banjo Build
« Reply #168 on: June 15, 2015, 04:11:27 PM »
Glad it arrived safely
Andrew Mawson
East Sussex

Offline S. Heslop

  • Hero Member
  • *****
  • Posts: 1154
  • Country: gb
  • Newcastle Upon Tyne
Re: Banjo Build
« Reply #169 on: June 15, 2015, 04:56:34 PM »
So am I! I thought it'd be a much narrower diameter.

Just remembered I'd forgotten to post pics of the aftermath.


Reduced to slag. The big rasp is still somewhat intact and I was hoping i'd be able to easily separate the files since along alot of the length it didn't fuse. But where that big lump of slag is they're well and truly fused. I'd have to get some more disks for the angle grinder to get it apart.

I think before i'll call it entirely quits, i'm gonna see if I can save that large rasp. I was looking at buying rasps and found that those French clowns from the video sell them for over £100 each, along with woodwork blog eejits saying 'quality tools that'll last you a lifetime and well worth the investment!', and that renewed my interest in trying to make one. I'm taking this rasp business very personally.

Offline Bluechip

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 1513
  • Country: england
  • Derbyshire UK
Re: Banjo Build
« Reply #170 on: June 15, 2015, 05:17:10 PM »
Being a dumb old fart, why all this fuss about rasps ?? Have I missed something ??

In my younger days, if I wanted to inflict hideous injury on some innocent bit of timber my weapon of choice would be a Stanley Surform in one of it's variants.

In my youth I had to use a thing called a 'Dreadnought' file on copper bus-bars and they were murderous damn things. Needed about 400HP to shift the abominations. Purple in the face,  going weak at the knees and hardly a copper shaving to be seen ...  :bang:

Off to me chariot, Sanatogen time ...  :palm:

Dave
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline S. Heslop

  • Hero Member
  • *****
  • Posts: 1154
  • Country: gb
  • Newcastle Upon Tyne
Re: Banjo Build
« Reply #171 on: June 15, 2015, 05:26:50 PM »
I've got one of those dreadnought files, but it's beyond dull. I keep thinking that the teeth are so huge that I could probably revive it by grinding the tops with a rotary tool. But with the size and shape of the teeth i'm not convinced it'd be useful for much.

I've also seen those surforms all over. I almost bought one a couple of weeks back, in fact. Couldn't find any large round/ half round ones though so I figured a rasp would be ideal for inside radii. I suppose maybe I could bend them into a half-round...

But most of the rasp fuss is just because it's something that I feel should be possible to accomplish, and so I want to do exactly that. I guess there's a little bit of interest in finding uses for old files as well. Maybe save a few from the terrible fate of becoming dorky knives.

Offline Lew_Merrick_PE

  • Hero Member
  • *****
  • Posts: 690
  • Country: us
Re: Banjo Build
« Reply #172 on: June 15, 2015, 07:18:43 PM »
My tuyere feed is made up of (4) 120 cfm 12VDC fans with an adjustable voltage regulator (built up from LM317 adjustable regulators) that allow me to feather the airfeed.  At full speed, I can get quite a "fire" -- and adjust it down to the merest of a "breath" feed.

Offline vtsteam

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6466
  • Country: us
  • Republic of Vermont
Re: Banjo Build
« Reply #173 on: June 15, 2015, 09:17:33 PM »
Well I gotta say I like rasps (though I don't own any expensive ones) and have had poor luck with sureforms. In fact only bought one, once, and wasn't too happy about that after. There's a big difference to me between a flexible piece of sheet metal like a cheese grater and a solid steel rasp. I guess sureforms must work maybe for rough work in softwood, but I'll take a simple 4-in-hand rasp and rat tail rasp for preference for most work I'd want to do, Of course more shapes is better, but those are the minimum for me. I'd be hard pressed without a low angle block plane, and chisels too.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 8966
  • Country: gb
  • East Sussex, UK
Re: Banjo Build
« Reply #174 on: June 16, 2015, 04:35:31 AM »
I gave up with Surforms - they'd be fine for the first ten minutes then rapidly declined in sharpness - I think that the formed teeth tend to bend back and put their heads under the parapet!
Andrew Mawson
East Sussex