Straight Edges

[classtimesailer]

My first frame will be made without a frame jig or an alignment table. What should I look for in a used straight edge? Would more than one length be helpful? It seems like I need 36 inches to go across the BB to the HT. Should I look for one that is ruled? How about stainless vs hardened steel vs aluminum (vs just a stainless ruler)? What would you use if you had no jig and no table? I've got plenty of time to wait for the "right" one to come along.
Jeff

[Jonathan]

There is a eBay seller named mikemetric or metricmike. He has a great selection of high quality measurement pieces in all sorts of lengths at really good prices.

[steve garro]

A piece of string ran from the outside of one dropout, around the HT and over to the other dropout.
Tool cost = $.04
- Garro.

[edoz]

If you want a straight edge, you've got a few options. The big drywall squares you can get at the hardware store work well, or you can even use flat bar stock. A 4ft piece of 1/4" x 2 or 3" aluminum would be fine. It's straight enough to reference a beginner's frame. I built 35 frames like that before I got an alignment channel.

[Will Outlaw]

Don't discount Garro's $.04 string or the sky, which is still free.

Sight from the outside of the seat tube to the inside of the head tube against the sky, adjust, tack, check and build away. If your miters are in phase it'll sort of want to be straightish anyway. :-)

The string and a true rear wheel take care of the rear triangle. A couple chunks of angle, some clamps and threaded rod help hold things in place if need be.

I built #2 that way and it came out really nice. And I learned a ton by not using anything more complicated than string and sky. It really helped me get a feel for how the frame was going together.

[steve garro]

Don't discount Garro's $.04 string.

The only string thoery I subscribe to.
+1 on the true rear wheel, too.
- Garro.

[Andrew R Stewart]

While strings are fine and for many steps work well enough it is nice to have a rigid device at times. That with a c clamp and your hands are freed up and a continual reference is had. Check out your local DYI and the steel or Alu channels that are usually in 3' lengths. Andy.

[echelon_john]

This is cheap and valuable, with or without a jig.

Park Tool Co. » FAG-2 : Frame Alignment Gauge : Frame & Fork Tools

[Jonathan]

String is great, but once in awhile you might want to measure something too.

[Martin T]

This is nice. Metric Flex Rules 173 1000mm 36 Inch | eBay

[steve garro]

String is great, but once in awhile you might want to measure something too.

Beyond a cubit or a thumb's width?
Too funny!
I'm a stainless ruler kind of guy.
- Garro.

[Jonathan]

The thumb between the stay and dummy wheel is my second measurement after I visually align with the wheel with the seat tube. After that I use the plate and the tools with numbers on them. So yeah, the thumb works and it's pretty accurate too.

[Will Outlaw]

I'm just amazed at how little actual tooling is required to build a straight bike, which isn't to say I don't lust after a mega-bucks jig, a mill, a lathe and the experience to use them all properly. I totally do.

But if you have the time some string, some sky and some patience can yield damn good results, especially if you're not building for a living. Throw in a tape measure and you're golden. :-)

[dsaul]

As someone who just used the straightedge method to build frame #1, I can add my experience and maybe save you some of the head scratching to figure out how to fixture each joint. This is the process I came up with and is by no means an expert opinion on how it should be done, so take it for what it is worth.

I used two 3' lengths of aluminum angle wide enough so it covers the diameter of the bottom bracket (2" worked well) and a number of different clamps (some c-clamps and woodworking clamps with padded jaws). I welded a 2" piece of flat plate onto one of the c-clamps so it would work for clamping the bottom bracket to the aluminum angle.

ST to BB joint - clamp BB to aluminum angle and then clamp the seat tube to the angle using spacers to keep the seat tube the same distance from the bottom bracket along the length of the seat tube.

DT to BB joint - use the same procedure with a different amount of spacers depending on the diameter of your downtube.

DT to HT joint - clamp the aluminum angle across the seat tube extending past the head tube and clamp the head tube to the angle. This will keep the head tube in the same plane as the seat tube. Once this joint is secured, you should be able to attach the top tube to the head tube and seat tube and the front triangle is complete.

Rear triangle - I clamped one piece of angle to the bottom of the bottom bracket extending back past the rear axle to keep the axle on the same plane as the bottom bracket. Then I clamped the other angle across the seat tube and down tube so it is parallel with the centerline of the frame. Mine was a road frame and the ST and DT were the same diameter. If yours are different, you'll need to do some math and use some spacers. Once you have this piece of angle parallel with the centerline, you'll have to do some math to figure out the centerline and clamp the rear dummy axle in place.

Again, this was just what I came up with as a first time builder trying to figure out how to build a frame without a jig. I hope this helps you to figure out a process that will work for you.

Dave Saul

[steve garro]

I'm just amazed at how little actual tooling is required
*snip*
But if you have the time some string, some sky and some patience can yield damn good results

Yeah, how about those Pyramids, huh?
(Says the guy with the new Anvil jig)
Seriously, one of the most often used tools in my shop is the 6" pocket ruler from California Bike Co-op.
- Phil, Stein, ect.....

Ok, Ok.......I do have a whole collection of little metal rulers, some collected from old man tool chests with the edges worn from wear and time....
One I've been looking for is a 3'/1 meter ruler, stainless, cork backed but fairly stiff, all the ones I have are pretty floppy.
- Garro.

[Doug Fattic]

photo.jpgphoto[1].jpg
Here are a couple of pictures of the straight edge I use. It is laying on one my alignment tables - which is one of the 1st and most important tools I would encourage anyone that wants to make a few frames to get. It (the straight edge) is 4 feet long and has a very fine threaded screw on one end. The screw itself has a knurled knob on one end for turning and a ball bearing for striking the surface on the other. I had a few made in case a student wants to buy one. I use it a lot making the rear triangle.

Making a frame without jigging (actually you have to use something to hold tubes together somehow whatever you want to call it or do it) with only a straight edge to check alignment complicates the difficulty increasing the chance of mistakes resulting in frustration. These motivation killers are the reason I use fixtures and a flat table in my framebuilding classes to build the front triangle. Most of my students have bigger ambitions than making just an occasional frame slowly. I do teach them how to build a rear triangle outside of a fixture because only the most expensive ones can get that right.

Besides using the end of the screw to check main triangle alignment (while the body of the straight edge is held against the bb shell with the pointer near the bb to establish position and then moved to be near the HT to see if it is the same), it can also be placed against the head tube and seat tube to check rear dropout spread alignment. The Park Frame Alignment Gauge (FAG-2) is made to do this job too. It is much easier and more accurate to do it with this tool than with a string wrapped around the head tube. The screw is set against the inside face of one dropout to see if it is the same distance apart from the main tubes as the other one. It can also be used with a true wheel to get the chain stays and seat stays exactly the same length (so the rear wheel centers). This takes away the need to build a rear triangle in a fixture.

In Ukraine where we are equipment challenged to make frames, we taped a hole in a long aluminum level to make a straight edge with an adjustable screw. Here is a picture of David (a student at the college where the frame shop is located) checking dropout spacing with it. Another picture shows the slab of steel plate we attached legs and post to make an alignment table. The simple fixture laying on the table is one a student made years ago. It is the kind most classic builders in England used when I apprenticed there in the 70's. It does away with the need for a full scale drawing.
IMG_0212_2.jpgIMG_2706.jpg

[Jonathan]

I'm pretty sure I'm in love with the Ukkranian vise stand.

[echelon_john]

If you're serious about a straight edge, you should really start here.

[Mike Mcdermid]

Yeah, how about those Pyramids, huh?
(Says the guy with the new Anvil jig)
Seriously, one of the most often used tools in my shop is the 6" pocket ruler from California Bike Co-op.
- Phil, Stein, ect.....

Ok, Ok.......I do have a whole collection of little metal rulers, some collected from old man tool chests with the edges worn from wear and time....
One I've been looking for is a 3'/1 meter ruler, stainless, cork backed but fairly stiff, all the ones I have are pretty floppy.
- Garro.

I thought it was only me that had an uncanny affinity to rulers of the 6" and 12" variety
they also have to be engraved to set a sribing guage or they get tossed

[steve garro]

they also have to be engraved to set a sribing guage or they get tossed

+1
And your compass.
- Garro.