Scratch Drag frame dimensions

waltsuz

waltsuz

New Member
#1
#1
Started bending up 1 inch DOM tubing and clamped it to a frame jig I made. I am trying to determine the dimensions for this build referenced off pictures and by eye off the jig. Here's what I got
Axle hangars are 14-1/2 inch's on center
Top frame rail to bottom frame rail is 18 inches o/s
Top frame rail from neck to rear is 42 inches
Wheelbase is right at 58 inches and I may kick it back to 60.
Clone 390, maxed GX390 after roller gets run, 205/50-10 rear wheel, hydro dual piston brake, TC for a start,
Would be interesting to hear comparisons to these measurements off others doing drag frames...
 
KB2ROCKET

KB2ROCKET

Active Member
#5
#5
while were on this subject I just want to say CHARLES I really really like that drag frame you have with the mid frame diaginal brace
 
waltsuz

waltsuz

New Member
#6
#6
Yellowhand said:
Nice work...should be a blast to ride when it's finished!

Did you mill the tubing joints or hand-cut them? They're perfect!
Click to expand...
I bought a tubing knocher from Harbor Freight. I had to shim it to cut on center but it works very well for 30.00. Uses a standard hole saw for the cutter. The cuts need de-burred but with a little time and set up it cuts perfect fits
 
waltsuz

waltsuz

New Member
#8
#8
walker32 said:
I am also about to build a dragbike from scratch and tryin to figure out some good dimensions to use yours looks very good
Click to expand...
I got the neck setting at 56 degrees. The rear bends for the axle hangers are 120 degrees. The bottom rails to the neck I still have to figure this bend and they will splice together under the motorplate. I found a piece to tubing to fit inside this DOM 1 inch for a splice. This will give me a backup for an open groove weld for 100% penetration on the welds. I figure I'll use a 3 inch piece to align the tubing to eliminate a dog leg or offset in the weld. All welds will be done with a TIG.
 
waltsuz

waltsuz

New Member
#9
#9
Having trouble finding time to work on this:
Wheelbase will be right at 60 inches, it keeps growing. The frame is wider than I would have liked because of the width of the rear tire and disc brake. The frame is 14 inches wide on the bottom from the axle hangers all the way to the front of the motorplate. I have a splice in the frame at the motorplate center. Rear axle center to bend at neck bottom is 27 inches.
Rear section was made from 2) 40inch pieces bent at 15 inches 120 degrees
Front section to neck is from 2) 39 inch pieces bent at 10 inches 35 degrees
All bends have a 3 inch radius. Top rail needs fitted to the neck and its ready to weld together. Any other frame builders out there???:shrug:
 
hemigremmy

hemigremmy

New Member
#10
#10
Looks really good so far, what are you using as a tubing bender? The notches in the tubing look great and everything butts up very nicely!! That thing is super wide!!!
 
Yellowhand

Yellowhand

#11
#11
waltsuz said:
Any other frame builders out there???:shrug:
Click to expand...
It's like you said...it's hard to find the time to work on minibike projects. We have 120 ft of 7/8" chromoly tubing set aside to make 3 or 4 frames, and we bought a new bender, but everyone's too busy to do anything right now.

We also have 7/8" and 1" stainless tubing in the rack, and I'd like to do a polished or satin-finished TACO copy with oversize dimensions so an adult can ride it comfortably.

I also want to give that HF tubing notcher a try...it's so cheap, the hole saw blade will cost more than the notcher.
 
waltsuz

waltsuz

New Member
#12
#12
I'm using a manual JD2 Model 3 Tubing Bender, its the $hit for this and well worth the investment

Outside to outside is 8 inches on the top and 14 on the bottom. I think when I get this GX390 in the frame and the 10 inch rear wheel in, it won't look so wide. Next one will have a straight taper in the bottom rails and I'll be able to make the frame sides out of one piece with no splices.
 
waltsuz

waltsuz

New Member
#13
#13
All tacked together and had to take a first look off the jig. Its super long and alot bigger that I thought. Hopefully it'll track straight really well
 
ivan_a_89

ivan_a_89

Banned
#16
#16
waltsuz said:
Having trouble finding time to work on this:
Wheelbase will be right at 60 inches, it keeps growing. The frame is wider than I would have liked because of the width of the rear tire and disc brake. The frame is 14 inches wide on the bottom from the axle hangers all the way to the front of the motorplate. I have a splice in the frame at the motorplate center. Rear axle center to bend at neck bottom is 27 inches.
Rear section was made from 2) 40inch pieces bent at 15 inches 120 degrees
Front section to neck is from 2) 39 inch pieces bent at 10 inches 35 degrees
All bends have a 3 inch radius. Top rail needs fitted to the neck and its ready to weld together. Any other frame builders out there???:shrug:
Click to expand...
when you say 60 inch wheel base from where to where are you measuring?
 
ivan_a_89

ivan_a_89

Banned
#19
#19
oh ok. damn that is one huge mini then. that think is 5 feet axle to axle
my bike is gonna be 46inche axle to axle i believe. but its just gonna be a small block.
bike is looking good though.
i like the angle on the front bars.
 
waltsuz

waltsuz

New Member
#20
#20
ivan_a_89 said:
oh ok. damn that is one huge mini then. that think is 5 feet axle to axle
my bike is gonna be 46inche axle to axle i believe. but its just gonna be a small block.
bike is looking good though.
i like the angle on the front bars.
Click to expand...
I am trying to get this to look like a drag bike. Here's a 750 frame project I did in the mid 70's from a weld together kit.
 
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