Hand built bespoke bicycle frames in the heart of the Wiltshire countryside - dmoframeworks@gmail.com.
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Saturday, 1 December 2012

BB thread tapped, final fit check done, frame fully brazed and logo released.....

Hello there,

well today saw me mainly trying to stay warm in the shed - what more of an excuse does anyone need to bust out the oxyacetylene and braze up a bike frame!!

However the first job to do was to tap the BB shell. The shell actually came threaded but during brazing various things get into the thread, such as hardened flux and bits of braze so its necessary to "chase" the thread out.

In actual fact it took more than a bit of chasing -  I ended up removing quite a bit of material. This was a bit worrying at first but regular checks during the process showed that all was good. So now, thanks to Mr Smith, I have a nice smooth BB thread - cheers buddy!

So I then installed the BB and cranks to check that everything fitted, ran smoothly and most importantly cleared all of the tubes - see pics below:
BB Installed - Mmmmm fillet brazed goodness
Crank to right hand chainstay clearance
Finally I have completed the DMO logo (see below) this is currently with Blade Engineering in Chippenham being water jet cut out for me in various thickness of stainless. This will then be affixed (brazed, glued, magic'd) onto the headtube.

So tomorrow should see the frame fully fettled, the chainstay stiffening tube added and the various braze ons, er brazed on.

Saturday, 24 November 2012

She's alive!!!

So, all in all, quite an exciting day today....

My aim was to finish the fit of the seat and chain stay tubes, check the lengths and alignment and then tack it all up and fit a rear wheel to make sure everything clears.

Before tacking the rear end up I needed to fabricate brass ring inserts to go into the stays at the drop-out ends. The reason frame builders do this is to ensure sufficient brass is present in the joint. Normal 'tube to tube' joints don't require this because they have a close fit all the way around whereas the dropout joint has a big gap in it where the flat plate dropout slides into the round tube - see pic below:

To make these little brass rings I just used the bits of brazing rod which had become too short to use for normal joints and wrapped them around a round file which just happened to the about the correct diameter!

Now when you slide the dropout into the cutout in the tube there is already brass present behind the joint.

Once I had finished fitting the brass inserts into the stays I could then tack up the rear end - and at last I can really start to see the frame taking shape.

Next up it was time to take the plunge and fit a rear wheel to make sure it cleared and sat in the middle of the frame. As you can see below the wheel fitted ok and cleared easily. I think a bit of 'tweaking' will be required to get the wheel to sit in the middle of the frame - but as far as I can gather this is par for the course with handmade frames!

When desinging the frame I accounted for anything up to a 2.4" tyre, in hindsight its unlikely that I will use such a large carcass tyre and so I could have got away with being a bit racier on the chainstay length and generally tucked the wheel in closer to the seatube - a development for frame number two perhaps?

The original aim was to get the frame to be sub 2kg, however when I guesstimated the frame weight during the design phase I found it hard to get an idea of exactly how much the fillet brazed joints would add to the overall frame weight. The answer is a lot!! I have intentionally ensured that each braze has nice large radii and so they are possibly a little over engineered for the application.

Including the sliding aluminium drop-outs the frame currently weighs 2.3kg, however I am yet to fettle the headtube joint so this might come down a bit. This is a bit disappointing but looking at competitor frames (Niner Sir 9, Singular Swift etc etc) its about par for the course.

Next up I need to tweak the left rear seatstay and then fully braze up the rear end. Following that I need to get a seatstay bridge bent up and get that fitted then its just the odds and ends of cable and bottle mounts and it should be ready for painting!!


Friday, 23 November 2012

Day 4, more learning, a couple of mistakes, but the frame is together.....

So today started with the relatively simple job of shaping the chainstay ends (the tubes for which were bent yesterday).

The right hand stay went pretty straightforwardly - and then I got distracted...

At the top of the seatstays the bend radius is quite tight, as such the tubes "crimped" and buckled a little bit. I had been wondering what I could do to remove these unsightly dents when I realised that I could potentially use the seat-stay bridge to hide them. 

Well that was it, full steam ahead on trying to bend a tube to an internal diameter of 75mm - so a test was in order.

I picked up what I thought was a scrap piece of tubing and merrily went to heating it up with the oxyacetylene and trying to get a nice bend - little did I realise that this was the pukka left hand chainstay!!!

After some shouting and looking at things to make sure I had just dropped a clanger I came around to the fact that this was the first set back I had had while making the frame - which wasn't too bad considering. And, when I thought about it, I wasn't overly happy with the chainstay as it was - so I set to remaking it - while doing which I learnt a valuable lesson.

I remade the stay and it lined up really well with the drawing, but then when I overlaid it with the existing stay (the one I didn't take a torch to) it didn't match that well - it was at this point that I realised, it would be much easier to make one tube and then just make the second one to match the existing tube - and not necessarily to the drawing. This way you end up with two perfectly matching tubes.

Anywho - enough of all of that - I then shaped and fitted both sets of stays and set to finishing the fillet brazes on the front triangle - see pic below:

Tomorrows plan is to add the lightweight pockets to the left hand drop-out and then tack up the rear end - if all goes according to plan I should be able to fit a rear wheel and tyre tomorrow to check for clearances etc - cheers Neil for the loan of a wheel equiped with a mud tyre!!

Thursday, 22 November 2012

Day 3 - it's starting to feel a bit like ground hog day....

The plan for today was to braze up the main triangle and bend the seat and chainstays.

If there is nothing I've learnt since building my own frame its that there is a heck of lot of learning to be done!! I've lost count of the amount of situations where I've had to think about 5 steps ahead tyring to not make a mistake or the amount of things I've done, got wrong, done again and possibly even got wrong a second time!

Anyway I digress, today I continued to braze up the front triangle but I ran out of brazing rod - so I bent the stays - see pic below.

Shaping the stays really has made the frame feel like its getting there - tomorrow will hopefully see me finish off the front triangle and pop into Johns Bikes Bath to get the BB shell thread cleaned up. 

Once I have got the BB shell thread cleaned up I can install the BB and cranks and make sure everything lines up (and clears) before I get too carried away with brazing up the whole frame.

Wednesday, 21 November 2012

Front triangle tacked and brazing begun.....

On the previous post I ended by mentioning that the seemingly simple task of brazing the front triangle turned out to be not as straight forward as I might have otherwise expected.....

The reason for this is the material from which I made the jig. To save money I made the jig out of wood, however it has been a month or two since I made the jig and mounted the aluminium fixtures on to it - in the correct location I may add.

The issue is that, having re-measured the jig prior to continuing with the frame, it would appear that the jig has swelled ever so slightly. This in turn put all of the aluminium fixtures out of position!

Having re-located the fixtures to the correct position I then continued with brazing up the BB shell - see pic below:

Next up I added the top tube and down tube to the jig, tacked it all together and fully brazed the seat tube to the top tube.

Tomorrow I will be finishing off the main triangle brazes and shaping the rear triangle tubes ready for their joining to the main triangle.


Internal cable routings finished & seat-tube slotted....

Having an excess of holiday I decided to take a week off and hit the frame hard - as such I have finished the internal cable routings in the top tube - what a nightmare this turned into...

The stumbling blocks I came across when doing this were:

1. Making the holes in the frame tube for the internal tube to poke out of.

To do this I drilled a hole perpendicular to the tube surface where I wanted the centre of the internal tube to exit the frame tube. I then angled the drill bit to cut an elliptical slot, this sort of worked however every time I got a nice ellipse on one side but then on the other side I ended up with an asymmetric cut-out.

2. Brazing the internal tubes into the frame tube.

This was fine at one end, but when doing the other end I didn't account for how much distortion you would get. Routing internal tubes through a straight frame tube should be straight forward enough, however I'm routing them through a curved tube (just to make things more difficult).

When I tried to re-bend the internal tubes away from the inner wall of the frame tube (so they don't hit one another when the bike goes over bumps) I cracked one of the internal routings - big fail!!

3. De-brazing the internal tubing while brazing on the exit surrounds.

Unfortunately when I was brazing on the frame stiffening bits, which go around the internal tube exits, the braze on the internal tubes softened allowing the internal tubes to move ever so slightly.

Anyway - after all of these issues were overcome I got the tube finished and also cut the slot in the seat-tube for the seat clamp - see pic below.

Next I will be tacking and brazing the front triangle, but as it would turn out this would not be as plain sailing as I might have at first thought......

Sunday, 21 October 2012

Internal cable routings started......but not finished!!

So before being able to join the front triangle together fully I needed to tackle the internal cable routings.

The main reasons for running the cables inside the top tube is that it will make fitting a frame bag easier and look cool!!

I did a lot of research into internal cable routings on the Internet and to be honest I didn't find out a great deal!

As such it looked as though a bit of experimentation was going to be the order of the day.

The first challenge was to bend the internal brass tubing at each end in order for it to exit the tube - this seemed straight forward enough - however the first attempt turned into an experiment into discovering the melting point of brass - it is low!!

The next try went much better so I thought I would take it to the next level and have a go at brazing on one of the cable exit shrouds - this resulted in the internal brass tubing melting!! This was becoming frustrating.

After a bit more of a play it looks as thought I was holding the heat on the tube for too long - by waving the heat in and out to locally heat the section being joined it meant the whole assembly didn't get as hot and only the bits I wanted to melt, melted.

Top Tube in Position With Guide Tubing Showing

The First Brazed Routing - 2 hours!!!
Next I need to braze the other three internal cable routings and shape the rear seat and chainstays.....

Saturday, 6 October 2012

Front Triangle - done stamp!

This afternoon I managed to get into the shed and mount the seat-tube support onto the jig - it then seemed only fair to shape the seat-tube and top tube and fit them to the jig also - see below:

Front Triangle 

I'm going to weigh all of the individual parts tomorrow but a rough guess so far puts the frame at just under 2kg without the braze.

Tomorrow I'm going to have my fist shot at internal cable routings.....

Saturday, 22 September 2012

The first two dots have been joined......

As described in my last post, the next step was to start joining all of the various "hardpoints" of the frame together with the tubing.

I still need to finalise the seat-tube, as such this one wasn't an option to shape, so instead I started work on the downtube, see pic below:

Downtube Done

Mitre to headtube - this one took 53 minutes, next time I think I'll do the hard mitre first and then the easy one.

Mitre to bottom bracket shell - the easy one!
One thing that sprang to mind while shaping the downtube is that before I braze it in place I will measure the length and maybe trace the mitres so that it will take me a fraction of the time to shape this tube on frame number two.

This did make me think that, should I wish to start making frames more regularly, some kind of automatic mitre-ing device would come in very handy indeed!

Next up I need to finalise the seatube and get hold of it so I can cut in the top tube.

Frame Jig Complete

A late night last Friday combined wiht a very late night last night has resulted in the frame jig being completed - see picture below.

Here we have (from the bottom clockwise) the seat-tube locator, the bottom bracket shell mount, the headtube mount and the drop-out mount.

Close up view of the drop-out mount.

Close up view of the headtube tooling.
Next up was to accurately mount this lot onto the jig back-board. In order to do this I printed out a 1:1 scale plot of the frame and the tooling.

I set the centre of the bottom bracket and this formed the datum for the location of all of the other aspects of the frame.

Next was to set the sliding drop-outs to horiontal and the rest was easy!

Marking Out
Mounted Tooling
Next up is to start joining the dots!!!

Thursday, 6 September 2012

Frame Stay Tooling & The First Bent Stay!!

The next step in the build has been for a while to pluck up the courage to start practicing with bending the tubing for the seat and chain stays.

This has been for me the most intimidating part of the build as it was the part I knew the least about and the lack of information on the Internet regarding techniques other people have successfully employed only served to make this task event more daunting.

I did find one picture of a stay bending setup on the net which was comprised of a set of form tools mounted in a fly press. This seemed pretty simple and after a quick chat with Piet (now my full time wood turner and general jig building consultant!!) we decided on a plan to make a set of tooling.

The picture below shows the turned piece of wood which will be used to form the basis of the bends in the tubing, for initial tests this will be mounted in a vice and the tube pulled around it to form the bends,

Turned Wooden Form Tool & Bar Clamp
Because I was so keen to test the tooling and also wanted to see if I could get away without needing a fly press I modified the turned block to incorporate a clamp to hold the tube during bending.

The next step was to have a play with bending a tube.

Tube Being Bent
This technique definitely requires some honing however the results of the first bent tube were pretty encouraging.

Chainstay Number One!!
At the moment these test pieces are being done using cheapo seam welded tube of the correct diameter. I need to do a couple more tests to accurately determine how far the centre of a bend ends up being from the mount in the form tool and I should be good to go on the real things!!

Next up should be a finished set of stays and even maybe all the bits on the jig ready for some brazing action!!

Sunday, 12 August 2012

I just couldn't resist.........

For those of you aren't aware of the Chris King Cielo bikes some of them come with some pretty nicely carved out dropouts - as such I couldn't resist the temptation in emulating them on the first run of element frames - check out the pictures below:

I'm not sure I'll be doing this by hand for all dropouts - they do come out pretty nice but it takes ages!!!

Paragon Dropouts Added to CAD Model

Having spoken with the splendid chaps from Paragon Machine works it turns out that they provide step files for all of their machined parts available on the website - this makes it super quick, easy and most importantly accurate to simply smash the parts into your CAD model - which is what I did on Friday - see image below.

Now I really need to crack on with making the drop-outs a tad lighter and shaping the seat and chainstays!

Wednesday, 8 August 2012

Drop-Outs Sorted

So having tried in vain to get my own design of sliding dropout manufactured I turned instead to the splendid chaps at Paragon Machine Works in Richmond, CA.

The drop-outs arrived on Tuesday and I couldn't resist getting the stainless steel bits super-finished - check out the pics below....

Left Hand Drop-Out::

Riight Hand Drop-Out::

So as you can see all of the bits are really nicely made, now all I need to do is jig them up ready to be joined to the rear triangle.

Check out paragon machine works for these and more splendid bike frame building supplies -

Wednesday, 4 July 2012

Top Tube Bending - Complete!

Having researched tube bending companies on Google I compiled a list of likely candidates (about 7 in all) - the first of which was a company called Pipecraft based in West Sussex (http://www.pipecraft.co.uk/).

I spoke with a chap called Andy who was so helpful I didn't even bother phoning the other companies on my list!

Having discussed my requirements (and essentially because I am generally interested in all things engineering) we decided that it was probably best for me to pop down and visit Pipecraft with my tubing.

This enabled me to watch and learn about the process of forming the tube and also served as a splendid opportunity to get a proper feel for their manufacturing capability for use on future projects.

In the end Andy rolled my 4130 tubing on a ring roller, we experimented with both sand filled and empty tubing and it turned out the bend was so shallow sand was not required to support the tubing - see pics below:

Andy in action on the ring roller!

Andy (with mesmerised Dad in background) demonstrating a tube mitreing belt sander.

All in all an excellent visit, 5 shaped top tubes and lots learnt about tube bending, shaping and fabricating.

Everyone at Pipecraft couldn't have been more helpful and I couldn't have wished to work with a more open and generally welcoming group of people - contact them for all your tube shaping needs ;) 

Monday, 2 July 2012

Tube Bending Pre-Work!

One of the design features of the Element frame is a very slightly curved top tube.

There are various reasons for this design choice the main ones being:
  • it results in slightly more vertical compliance in the front triangle - aimed to provide a more comfortable ride over multi-day events while maintaining lateral stiffness and hence frame responsiveness.
  • it enables a slightly larger frame bag to be fitted to the frame (essential for balanced bivvy bike setups)
  • finally, and arguably least importantly, it differentiates the frame from anything else currently on the market!
 In order to achieve this "shaped" top tube it was necessary to cold form the tubing - I did a lot of research into this with various techniques being suggested including:

  • fill the tube with soapy water and freeze it prior to shaping (the soap apparently acts to stop the ice crushing and cracking up under load).
  • fill the tube with Bendalloy prior to shaping
  • don't bother filling the tube with anything
  • fill the tube with water and then pour in fine sand - the water acts to ensure no air is trapped in the filled tube.
In the end I decided to sand fill one tube and to not fill one tube and test bend them back to back.

In order to stop the sand coming out during shaping it was recommended I bung the ends of the tube with wood.

For this I turned to my friend Piet from work who not only has a wood lathe but is also pretty handy at using it!!

We used some old South African railway sleeper wood (Piet is originally from SA) and proceeded to turn the bungs on the lathe - see pic below:

Piet in action on the wood lathe!!
The finished bungs prior to parting off and finishing.
The bung in situ - job done!

Many thanks to Piet for showing me how to make the bungs on his lathe, putting up with my slightly optimistic manufacturing tollerences, and for providing some splendid Portuguese red wine to oil the wheels of creativity!!

The next step is to take the tubing to a company called Pipecraft to get it bent.

Thursday, 28 June 2012

Bottom Bracket Jig Complete!

So here we have the assembled bottom bracket fixture (the bottom bracket shell is the dark tube bit sandwiched between the knurled nut and aluminium bottom locator).

The studding is just cheapo 12mm stuff from B&Q (£3.50ish for a meter).

And here we have the exploded assembly to show you the internal detail. Hopefully if I start making a few frames I can get all of this re-manufactured in precipitation hardened steel to make it a bit more hardwaring.

 Next up will be the seat-tube locating nut and mounting plate......

Tuesday, 26 June 2012

Sunday, 24 June 2012

This is DMO Frameworks

DMO Frameworks is a frame building workshop based in Chippenham, Wiltshire.

DMO stands for 'Dennis Michael Oliver', Dennis is my Granddad (a retired fabricator and sheet metal worker from Jaguar), Michael is my Dad (a retired engineer from BMW) and Oliver is me (a Mechanical engineer).

My first frame (currently under construction) is aimed at Bike Packing mountain bikers. In a nutshell Bike Packing entails strapping all your kit onto a bike for one, two or more nights out in the wilderness!

The frame itself combines various grades and thicknesses of off the shelf and custom steel tubing to make a frame which is light, stiff where it needs to be and importantly compliant enough for comfortable multiday riding.

When taking part in multiday Bike Packing events exciting singletrack can be few and far between - it is for this reason that a frame which makes the most of these infrequent highlights should hopefully serve to make Bike Packing that much more enjoyable - that is the aim of the DMO Element.
In the coming weeks (and hopefully not too many months) I will chart the progress of my first frame here on my blog - hope you like it!!