first time header builder some helpfull hints?
Staging Lane
Joined: Sep 2008
Posts: 60
Likes: 0
From: Chicagoland
John deere black (muffler paint) is another great header coating, it comes in a rattle can, lasts forever, and is available at any john deere dealer. A guy that builds high end hot rods turned me on to this and i have used it for anything i want flat black. It is awesome!!!!
TECH Apprentice
Joined: Jul 2004
Posts: 374
Likes: 1
I've built a few sets for cars and airplanes. Here are some of my tricks-
...
-Make a jig to cut the mandrels. I made one to fit my bandsaw that would cut the tube square at any angle.
-Cut your bends square (see note above) You can also use a piece of paper and a marker to make a mark and cut them square, but it is kind of tedious
...
If you want to see some photos, let me know and I'll gin some up.
Phil
...
-Make a jig to cut the mandrels. I made one to fit my bandsaw that would cut the tube square at any angle.
-Cut your bends square (see note above) You can also use a piece of paper and a marker to make a mark and cut them square, but it is kind of tedious
...
If you want to see some photos, let me know and I'll gin some up.
Phil
thanks
I must have put it somewhere where I can't find it but let me see if I can describe it to you.
The jig positions the mandrel bend in the vertical bandsaw so that the blade always cuts normal to the surface of the mandrel bend.
It consists of two plates, the bottom one is MDF and the top one is .125 aluminum,
The bottom plate has a rail on the bottom that fits inside the guide grove on the table of the bandsaw so the fixture can be pushed through the bandsaw to make the cut.
The top plate is fastened to the bottom plate with one pin located at the center of the radius of the u-bend. There are blocks of wood that locate the u-bend such that its radius is centered over pin.
To get angle cuts the top plate is moved relative to the bottom plate and secured with a clamp. The mandrel bend is clamped to the assembly for a cut.
Hope this all makes sense. I will keep an eye out for the jig and post up pics if I find it.
Phil
The jig positions the mandrel bend in the vertical bandsaw so that the blade always cuts normal to the surface of the mandrel bend.
It consists of two plates, the bottom one is MDF and the top one is .125 aluminum,
The bottom plate has a rail on the bottom that fits inside the guide grove on the table of the bandsaw so the fixture can be pushed through the bandsaw to make the cut.
The top plate is fastened to the bottom plate with one pin located at the center of the radius of the u-bend. There are blocks of wood that locate the u-bend such that its radius is centered over pin.
To get angle cuts the top plate is moved relative to the bottom plate and secured with a clamp. The mandrel bend is clamped to the assembly for a cut.
Hope this all makes sense. I will keep an eye out for the jig and post up pics if I find it.
Phil
TECH Apprentice
Joined: Jul 2004
Posts: 374
Likes: 1
I must have put it somewhere where I can't find it but let me see if I can describe it to you.
The jig positions the mandrel bend in the vertical bandsaw so that the blade always cuts normal to the surface of the mandrel bend.
It consists of two plates, the bottom one is MDF and the top one is .125 aluminum,
The bottom plate has a rail on the bottom that fits inside the guide grove on the table of the bandsaw so the fixture can be pushed through the bandsaw to make the cut.
The top plate is fastened to the bottom plate with one pin located at the center of the radius of the u-bend. There are blocks of wood that locate the u-bend such that its radius is centered over pin.
To get angle cuts the top plate is moved relative to the bottom plate and secured with a clamp. The mandrel bend is clamped to the assembly for a cut.
Hope this all makes sense. I will keep an eye out for the jig and post up pics if I find it.
Phil
The jig positions the mandrel bend in the vertical bandsaw so that the blade always cuts normal to the surface of the mandrel bend.
It consists of two plates, the bottom one is MDF and the top one is .125 aluminum,
The bottom plate has a rail on the bottom that fits inside the guide grove on the table of the bandsaw so the fixture can be pushed through the bandsaw to make the cut.
The top plate is fastened to the bottom plate with one pin located at the center of the radius of the u-bend. There are blocks of wood that locate the u-bend such that its radius is centered over pin.
To get angle cuts the top plate is moved relative to the bottom plate and secured with a clamp. The mandrel bend is clamped to the assembly for a cut.
Hope this all makes sense. I will keep an eye out for the jig and post up pics if I find it.
Phil
I can tell you're basically making a crosscut sled for the table and obviously you're using the center of the radius as your pivot point, but I'm having a problem imagining how the blocks work and how the top plate holds it down... I'm guessing that the blocks and top plate are adjustable for different diameter and radius tubes, otherwise, if you have a lot of one diameter/radius tube that you cut it would be easy enough to make a sled with a piece attached to the middle that has the same OD as the bend that you're using ID mounted with the center of the radius inline with the direction that the blade will cut... that way you could just rest the bend on the sled against the radius and go... but again, then you'd need a different setup for every different bend you used.
Your understanding of the fixture seems pretty correct. it is just a sled that pushes the mandrel through the bandsaw to get a cut normal ot the centerline of the tube
I tend to make my headers with predominatly one radius of bend, and that's how the jig was set up - for just that one radius of bend.
When I buy my mandrel bends I buy mostly the one size, but i buy a few of a smaller radius as 'problem solvers'. I cut these by hand on a vertical bandsaw (an old Rockwell wood bandsaw with a jack shaft on the motor to slow the blade enough to cut steel).
The blocks position the mandre bendl so the centerline of the bend corresponds to the pin. The top plate is held to the bottom plate with some quick release clamps as is the workpiece to the top plate. Nothing fancy.
You don't absolutly need the fixture anyway - it just makes it quite a bit quicker, especially if you're making symetric headers and you mark the fixture with the cut positions to fab the second side quicker.
For cuts on odd radius mandrels, I just take a strip of paper and wrap it around the tube where I want to make a cut and position it so it is 'normal' to the tube centerline and mark it with a Sharpie or spray Dychem. I dress the cut on a stationary belt sander to get a no-gap joint.
I tend to make my headers with predominatly one radius of bend, and that's how the jig was set up - for just that one radius of bend.
When I buy my mandrel bends I buy mostly the one size, but i buy a few of a smaller radius as 'problem solvers'. I cut these by hand on a vertical bandsaw (an old Rockwell wood bandsaw with a jack shaft on the motor to slow the blade enough to cut steel).
The blocks position the mandre bendl so the centerline of the bend corresponds to the pin. The top plate is held to the bottom plate with some quick release clamps as is the workpiece to the top plate. Nothing fancy.
You don't absolutly need the fixture anyway - it just makes it quite a bit quicker, especially if you're making symetric headers and you mark the fixture with the cut positions to fab the second side quicker.
For cuts on odd radius mandrels, I just take a strip of paper and wrap it around the tube where I want to make a cut and position it so it is 'normal' to the tube centerline and mark it with a Sharpie or spray Dychem. I dress the cut on a stationary belt sander to get a no-gap joint.
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Verdad Gallardo TECH Apprentice
Joined: Jul 2004
Posts: 374
Likes: 1
I usually just use a hose clamp to get a pretty accurate line (it will only want to tighten down when it's the closest to the radius line)... usually I start by using the clamp to draw a line, but sometimes I get lazy and just cut along it (eventually you tag it enough times that you ruin it... oh well).
Unfortunately, I usually have all sorts of different radii and diameters, and it sounded like you had something easily adjustable.
Unfortunately, I usually have all sorts of different radii and diameters, and it sounded like you had something easily adjustable.
