Using a Pino Morroni Frame Jig

Posted on November 14th, 2008 by admin under Bikes.

Picture 1: When doing a fillet joint (BB) I cut the ST miter and using a machinists square adjust plumb. I then install BB shell and center using vernier caliper (pic #2). Keeping the seat tube vertical I then braze to shell. You can use the movable distance gauge (Delrin spacer) to assure plumb.
I then rotate BB/ST to desired angle using the angle finder. Note: Seat tube offset can also be measured to determine the angle (thanks Omar). I then miter chain stays with dropouts already installed. Set your BB height and braze to BB shell.
Pic#4 shows the relative axle position if the wheel was installed. This for setting/marking the nominal bottom of the head tube.
(Click on pictures to enlarge)

In this set of photos, I’ve set the top tube height and top tube length as per design drawing. The miters are cut and the head tube angle is set. At this point I’m doing a cold fit to make sure that the miters are correct and nothing is binding. Last I’ll cut length and miters for the down tube. I’ll finally disassemble, flux everything up and reinstall in the jig for brazing. Presto-change-oh. I have a nice, straight, and fully brazed frame ready for any necessary cleanup of the welds.

(Click on picture to enlarge)

In these three above I’ve reinstalled it in the jig, fluxed up the joints and brazed up everything. Tomorrow the seat stays and dodads, a little clean up and it’s off to the paint booth. This is the first time for using Fred Parr’s Brazage Pro silver for lugs. It’s also the first frame since I lost an eye a year ago. I’m getting better at putting the rod at the right spot at the right time, but as you can see I did get a couple spots a bit hotter than I needed to. I’ll soak it over night and see how it looks in the morning.

(Click on picture to enlarge)

Well, after an overnight soak and a few minutes with a stiff wire brush the frame is ready for a little dressing around a couple spots on the lugs and a bit of radius clean up work on the fillet. I said last year about this time that I didn’t think I’d be able to build bikes with one eye.  I wouldn’t call it a miracle by any means but, the progress has been good. However, this little article was about the Morroni jig and  as you can see after a days work and little fuss  I have a fixie I can sell.

I spent a day on the fork, mostly fretting over what to use and dinking around with the blade length cutting fixture (scroll down) and another with the frame assembly and a third (today if I remain engaged) to do the seat stays and braze-ons.  I’ll put up a picture or two when its got the next day into it just to make the process complete.


We’re having a great mid November weather weekend for riding so I haven’t been as diligent as hoped finishing up this frame. As promised here’s the finished basic frame, except a couple braze on bits still to add.  I haven’t decided if this will go out as a plain vanilla variety or if I’ll doll it up with some silver smithing adornments.  In the mean time..(Click on Pic to enlarge)

Here I’ve coal slag blasted the raw fillet to expose any gaps, pockets and wrinkles, then I shape and file to taste. This is like blocking done on body panels. The change in color helps to show high/low spots when a file is pulled across the dull surface.

Here is the last set of Zeus track drop outs in the world..maybe? Dave Bohm at Bohemian Cycles tells me he has near copies available. Thank God for artisans.

Here’s the head tube detail. I used an old Columbus groove tube. It may end up as a brake less fixie but I’m not going to mess around with liability issues by not making it brake compatible.

Here it is.

The crown is an 7mm offset Cyclo (?) for track blades. Old GPM brake bridge re-enforcements. MAX chain stays

and I don’t know what the seat and down tubes are.. Hey, it’s a mutt, but I love it so far.

Specs. are 54.5cm seat tube; 55cm top tube; 73.5 degree seat angle; 74 degree head angle; 5.6 cm drop; 95cm wheelbase; fork rake 32mm plus offset


And here is the frame painted, decaled and awaiting it’s new home..

(Click on photo to enlarge-click again to zoom in


  1. Karl Meyer Says:

    Hey Cool Frame:

    I like to live dangerously and the frame is my size! If you are going to sell it, what price do you want. I won’t need brake fixings either…

    Feel free to email me:

    Karl Meyer
    1974 Midget- Last of the Chrome Bumpers
    1960 BT-7 FrankenHealey- Building a Healey in pieces sounded okay at the time
    1978 Trans Am- Just Because I wanted it!

  2. Dave Says:

    I’ll figure out a price when it’s finished..DP

  3. James Says:

    This is pretty cool

  4. steve garro Says:

    cool, dave! i’d like to see some closeups of silver fillets on mainframe tube jusctions, please!! steve.

  5. Dave Says:

    Next time. It’s already painted and gone.

  6. RYErnest Says:

    Nice post u have here 😀 Added to my RSS reader

  7. Dave Says:

    Curious how an individual in the UK stumbles upon blogs like this one??

  8. Pino Morroni… A Retrospective « The TandemGeek's Blog Says:

    […] also wrote a blog entry entitled “Using a Pino Morroni Frame Jig” that included another extensive photo gallery along with his narrative that describes the […]

  9. Beam Style Jig Says:

    […] Jig Dave Porter did a nice write up a while back detailing the use of his Morroni beam jig Using a Pino Morroni Frame Jig. I have the tandem version of that jig and I like it a lot. Great access and very versatile. […]

RSS feed for comments on this post. TrackBack URL

Leave a comment

You must be logged in to post a comment.