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PostPosted: Sat Nov 26, 2011 8:11 pm 
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Joined: Sat Feb 09, 2008 8:06 pm
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Location: Visalia, CA
Alright. I completed my bending machine today. I have not bent anything with it yet.
Here is what I did. I didn't have real plans, but there are some dimensions/drawings in the Jim Williams book that I started from, and then used pictures of Fox style benders to come up with this "new and improved" version (tounge and cheek here guys).
I had shop grade 3/4" plywood on hand, so I used it for most of the frame. It splinters a little, but for the most part it worked fine, just not as pretty as it could have been. I already had the springs, the screws, the wire, the waist support (a 1095 knife blank). I purchased the conduit for the mold, press screw, light bulb bases, bulbs, count down timer and box, oven thermometer, and the stainless steel slats (I still have one slat coming, I messed up and only ordered enough steel for one).
It really went together pretty easily and quickly, I just spread it out over a couple of weekends. The bulbs are 2 x 150 watt and 1 x 200 watt.
The pictures are not for you pros who are, or have sold benders before, but for you guys contemplating making one of these benders. I don't know for sure if it is going to work, but it is suppose to work because they've been around for ever, right?
My first bending will be some cherry and I hope to do that in the next couple of weeks after some trial runs. I already have the plywood cutouts for an OM mold and will make that soon too. I'll have to make a waist caul for the OM, but discovered that it is really easy to change the caul on this, so that is no big deal. This seemed much simplier than making some adjustable caul...all the pieces,etc.
So here it is. I hope to have a bunch of these for sale next year for Black Friday!!!

Kevin


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PostPosted: Sat Nov 26, 2011 8:13 pm 
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Location: Visalia, CA
A few more closeups.

Kevin


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PostPosted: Sat Nov 26, 2011 8:36 pm 
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Joined: Sat Apr 10, 2010 10:50 pm
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Location: Seattle
Nice job of the bending machine.

The one thing I do not get is the bar that is attached to the spring and indexes into your form. How does it get past the side? It seems like the bar should just be used to index the form and the spring should be attached something that is on the sides or on top of the press.

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PostPosted: Sat Nov 26, 2011 9:14 pm 
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Joined: Fri Mar 03, 2006 7:09 pm
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Location: Hegins, Pa
be careful of the light bulbs . never let this unattended .

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Blues Creek Guitars Inc
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PostPosted: Sat Nov 26, 2011 9:25 pm 
You need to add a reflector on top of the bulb receptacles -- you can use a piece of thin ply or Masonite. cut three holes just large enough to match the sockets, it should fit snug in the frame -- cover it with metal furnace tape. If you don't do this the heat is going to melt the solder joints in the receptacles and more importantly it will melt all the insulation off your wiring. Start to finish our bulb heated units are only on a total of 30 minutes.


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PostPosted: Sat Nov 26, 2011 9:48 pm 
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Location: Visalia, CA
John,
The waist support bar; it sits under the side sandwich, the side is between it and the waist caul. Something about supporting the side at the waist during the bend. I don't see it used when a heat blanket is the heat source, but Ken Cierp always says this is needed, and was part of the original Fox design, right Ken? I've heard it probably is not necessary on the dreadnaught, but in the tighter waisted patterns it helps to keep it from cracking there. I imagine it can't hurt to have it there either.

Ken, I saw one guy who did the reflector thing. I can still do that easily, so I'll do it and have that added safety net. I've got 1/4" ply and lots of furnace tape. The count down timer is a 30 min. deal. I would have no reason to leave the bender while it is in operation and will not let that become part of the equation. I understand lots of builders have used light bulbs for decades and I can learn to use them too!

If I can't learn the "light bulb" method, I can always purchase a blanket!!

Kevin


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PostPosted: Sat Nov 26, 2011 10:47 pm 
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Joined: Sat Feb 09, 2008 8:06 pm
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Location: Visalia, CA
I was thinking about holding a propane torch just inside the waist area of the mold to get more heat in there? Ha.
What did guys do for the waist area before silcone blankets were invented?

Kevin


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PostPosted: Sun Nov 27, 2011 8:20 am 
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Joined: Fri Mar 03, 2006 7:09 pm
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Location: Hegins, Pa
Blankets will allow you better control of heat and bending . We also have heating blankets and controllers for the waist area . Bending the waist last will help with process repeatability but I found with the light bulb units you always had to touch up something .
If you can get it in the mold , and you can use a spreader to work the shape that is all you need. Tighter designs may need touch up with a hot pipe , it wasn't until I started using heat blankets that the bender really worked. You are relying on refractive heat and with a blanket , it is contact so you can control heat so much better. That is not to say your bender won't work it just won't work as well .
I am done bending in less than 5 minutes . I also bend a lot more than most people. This year I am closing in on 300 sets bent . Nice machine and it should last. . Want are you using for slats ? I found with Stainless and Spring Steel you don't need that bar , in fact that bar is more for location so the pattern is held on point for the waist cawl.

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PostPosted: Sun Nov 27, 2011 11:56 am 
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Location: Hegins, Pa
getting the bouts down helps to get the heat into the tighter waist area . I did partially bend the waist to about 1 inch from the bottom . There are many techniques for using these things . I like to bend the larger radii first to let heat work.

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PostPosted: Sun Nov 27, 2011 2:59 pm 
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Joined: Mon Mar 13, 2006 12:34 am
Posts: 608
Location: Wilmette, IL
Nice job, Kev, I am going to take some notes! I have been planning on redoing my bender....it works well, but is very awkward to use, especially with cutaways. I like what you have done. Interesting discussion on bending order though.

I typically heat both metal slats up empty, then sandwhich the wood when they get hot enough. First thing I always bend is the waist, and have not had an issue there except for one peice of zebra I knew I was going to have a problem with as soon as I picked it up. I felt once that bend was done, the bouts were easily done in less than 2 minutes.

I like the idea of installing the metal slats on the form, but I can see where the waist will need to be pre-bent to use it properly. Not sure I like that idea very much.....I have historically done very poorly with a pipe bender.

I never thought of using conduit, Kev. I like it....I can get it cheap too, compared to solid bar for the forms.

I lined the inside of all of my forms with tinfoil. I just used spray-mount adhesive, sprayed the inside of the form, stuck the tinfoil on it, then trimmed the excess. AS for a reflector in the base....I bent a scrap peice of duct sheetmetal into a U-shape, and screwed it to the base of the bender. My ceramic fixtures get screwed into the U-Channel, and all wiring goes through the base into a chamber beneath. The sheetmetal reflects all heat towards the bulbs and bending form....it stays cool underneath, so no problems with the soldering or wiring overheating.

Aside from a 15 minute timer, I also have a dimmer to reduce temperature if I fear it is too hot for certain woods. I can get it to temperature, then reduce it enough to keep the wood workable but not too hot.

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