Hi Guys,

I wants to share my some what unique haynes roadster build. Recently I got my hands on drawings for a small (5" long 4 stroke / 4 cylinder engine with the intention of having a go at making the engine using my lathe and milling machine.

However, after spotting the haynes roadster book on my book shelf, I thought.... what if I build a working scale model of the haynes roadster and power it with this engine.

I have always wanted to build a kit car - more for the build than the drive - but don't have the space. This would be the perfect technical project to keep my mind bust!

So that's have I've done.... or started. So far I have completed the chassis based off the haynes roadster book as a scale of 4.5:1 (scale was based on the length of the mini engine vs. the length of a 4 cylinder engine that might be used in the haynes roadster)

I am making videos of my build and sharing them on youtube. I will also keep this post updated with progress.

There will be some complex aspects of this project to say the lease (e.g. building my own gearbox, clutch and diff)

I may times require information from some of you on here for dimensions etc of things that aren't detailed in the book.

Anyways.... here are to two project video I have uploaded so far.

I'll follow this with interest. No doubt you are aware of this, but I will post it just incase others haven't seen it...

Brilliant video! Thanks for sharing!

Interesting project!

I thought of that Ferrari video above as well!

I'm hugely impressed by what you are doing and, inspired by your use of SketchUp, I've taken out a 28 day free trial. To buy it isn't an expensive package and although it isn't parametric it does have loads of excellent features. I'm on day three of the trial and am currently working through a tutorial building a children's playground. It will be some while before I am sufficiently proficient to draw my chassis.

The package should carry a warning because by Jove it is really addictive.

Hi John,
It is a great design tool.

I just use the free online version - it works in your web browser and its free with no time limit.

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Originally posted by Mr - Mechanical
Hi John,
It is a great design tool.

I just use the free online version - it works in your web browser and its free with no time limit.

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Hello all!
This weekend I finished making the wishbones. Again I used the dimensions from the book and scaled them down. I've basically used the critical dimensions for these parts and then had to do some design work myself for the rest of it.

For example - on the front wishbones where full size car ball joints are used - well these parts aren't available at the scale I require. So i've altered the design slightly so that they are threaded in the ends (similar to the upper rear wishbone) and so utilize an incredibly small M3 male rod end connector.
These provide the same movement required for the suspension / steering as would be provided by the full size car ball joints.

The other difference is that I've machined the wishbones from 8mm alloy plate rather than fabricating from steel tube.
For parts this size, machining felt more practical than fabricating and on the up side - alloy parts will be lighter.

For any of you that haven't experienced it drill small diameter holes in aluminium is very challenging. Aluminium becomes 'sticky' when milled / drilled and so sticks to the flutes in your drill - especially when drilling relatively deep holes, once the flutes are full and the removed material has nowhere to go - well the drill become stuck and breaks. (I was drilling a 3mm hole 30mm deep when it happen )

To over come this I found it worked best to 'peck' drill - drill 5mm pull out - drill another 5mm pull out - each time cleaning the aluminium from the flutes. WD40 also helps as a cutting oil at this helps prevents the alloy stick to the drill - but pecking still required.

Something else for me to look at over the next couple of days is the welds around the suspension brackets on the chassis. A few brackets have some excess weld which need filed / dressed. Currently this excess weld in some locations is preventing full travel of the wishbones.

In the next video I'll be making the rear uprights - again these will be machined from aluminium. I plan to make then very similar to the book design including the bolts holes for the fixing of a hub / bearing carrier which I will be making as a separate part.



[Edited on 13/4/20 by Mr - Mechanical]

I really enjoyed the video which is a great way of presenting your project. Are you a toolmaker by trade or model engineer? I had no idea rod ends are available down to M3 but great that they are for this application.

I'm looking forward to the next video. Well done!

Hi John,
I work for an engineering company but in project management - I've always wanted a milling machine and lathe and so last year I got one. So playing with my milling machine and lathe is just my hobby.

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Originally posted by Mr - Mechanical
Hi John,
I work for an engineering company but in project management - I've always wanted a milling machine and lathe and so last year I got one. So playing with my milling machine and lathe is just my hobby.

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Reminds me of the scale of parts when I had a 1/10 Schumacher radio controlled car when I was younger, although it wasn't as finely engineered as scaled rod ends! I was thinking "where will he get his coil overs from" and remembered that my R/C car had oil filled (and adjustable!) coil overs, although I guess with lathe and mill you could simply turn some up yourself!

Hi

Well, I can and have made a locost from scratch, but I couldnt build one to scale at this size, well out of my skill set !

Im enjoying the vids

steve

So over the last couple of days I've been machining and fitting the rear uprights. Video below.

Again I've based the critical dimension off the haynes book but I did make so minor adjustments following a measure up of the 'as-built' chassis.

The uprights have been made from aluminium. Any my intention is to make a hub carrier similar to the sierra rear hub carriers as per the full size haynes roadster. (If anyone could give me the dimentions of a sierra rear hub carrier - from face of upright to outer face it would be appreciated)

The challenge with making these parts was the angles and work holding. But fortunately I found a very usefully tool for this.

Next on my to do list is to make the front uprights based on the geometry of the cortina front uprights and I'm also looking at the design of the rear differential.



[Edited on 8/5/20 by Mr - Mechanical]

Another fascinating video; thank you for sharing it with us. I'd certainly be interested in purchasing the device for setting an angle of a face so that you can machine it on the milling machine. I would find that really useful. Could you drop me a link please?

Many thanks

John

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Originally posted by John Bonnett
Another fascinating video; thank you for sharing it with us. I'd certainly be interested in purchasing the device for setting an angle of a face so that you can machine it on the milling machine. I would find that really useful. Could you drop me a link please?

Many thanks

John

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So today I finished and fitted the front uprights

I based the critical dimensions of this part off a ford cortina front upright.

Again I made this part from aluminium. This part is a little more complex than the rear uprights but I produced autocad drawings from r each machining process to make it easier for myself.

Hope you enjoy the video

I've also bought an old front brake caliper from a ford cortina so I can measure it for for a scale model.

If anyone has an old rear brake caliper from a Sierra that I could have please let me know.

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Originally posted by Mr - Mechanical
I've also bought an old front brake caliper from a ford cortina so I can measure it for for a scale model.

If anyone has an old rear brake caliper from a Sierra that I could have please let me know.

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That is the plan. See how it works out. I'm doing the drawings at the moment.

It been a while but I've made a little more progress on the mini kit car.

This time I've made the steering rack. I wasn't able to make a scale version of the escort rack as the size of the part would have became too small so the rack is of my own design and includes a rack and pinion like a traditional steering rack. (not like rc steering)

The challenge this time came with cutting gear teeth on the rack. (i bought the pinion gear) As the rack was made from 6mm rod I had to make a clamping fixture to reduce vibration when cutting the teeth.

Overall I've really happy with the rack.

Looks like this is up for sale on Ebay now :-

Ebay Link

Shame - Would have been great to see it finished

I really enjoyed the thread and watching the videos and to see the part finished creation appear for sale on Ebay is very disappointing. The builder must have had a very good reason for discontinuing the project but one thing I am certain of it wasn't due to lack of talent or a desire to see it finished. The quality of the work is extraordinary particularly from someone who isn't a tool maker or model engineer.

[Edited on 23/12/20 by John Bonnett]