Alfa powered build.

Follow progress of your fellow builders. Pictures encouraged!
ChrisS
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Re: Alfa powered build.

Postby ChrisS » 21 Feb 2019, 14:10

Another few hours, another pile of metal shavings and dust.

(mostly) finished the front section of the tunnel cover. I'll probably fill the gaps left at the top. Probably....  Don't fret, the floor won't be made from Contiboard in the final version.

first section almost complete.jpeg




And made a start on the main section of the cover. This was the easy bit. Gets tricky now as I have to bring the panel out to clear the pipes while still clearing the seat.

main section left side part 1.jpeg


And one for Kurt - the throttle pedal. :)

throttle pedal.jpeg
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Jonathon
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Re: Alfa powered build.

Postby Jonathon » 21 Feb 2019, 21:35

That tunnel is looking great! Using the tubing for the radius and the frame is brilliant.

ChrisS
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Re: Alfa powered build.

Postby ChrisS » 22 Feb 2019, 00:14

I was pondering ways to do it when Bad Obsession released a Binky episode showing how they did their tunnel cover.....so I copied ;)

Jonathon
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Re: Alfa powered build.

Postby Jonathon » 24 Feb 2019, 22:17

I just started watching those videos yesterday! It's my new favorite.

ChrisS
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Re: Alfa powered build.

Postby ChrisS » 25 Feb 2019, 02:22

Few more ugly aluminium welds. Good job I'm grinding them - they are nasty!

tunnel left side WIP.jpeg



tunnel cover right side WIP.jpeg





Pretty happy with the fit so far, even if it ain't pretty at the moment. It would be nice to have the skill to leave them as welded....but I don't.
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ChrisS
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Re: Alfa powered build.

Postby ChrisS » 01 Mar 2019, 14:07

Tidied up the tunnel cover and made it fit. Amazing what an hour or two with a grinder can achieve....

tunnel cover from right side.jpeg



Had a bit of a fight with the passenger seat clearance as expected, so had to add an extra 'feature' to allow for that. I'll dress it up a bit before I'm done but it's not too shocking - certainly not as bad as it appears in the picture. It distorted a bit as I was whacking it, evidenced by the irregular gap to the bulkhead, so once again, it needs some persuading back into shape but it was close enough to test-fit the seat.


tunnel cover from left side.jpeg



Very little of it will be visible once the seats are in.


tunnel cover with passenger seat fitted.jpeg


tunnel cover both seats fitted.jpeg



Just need to fit a couple of top plates front & back and figure out a way to attach a removable cover that can carry the handbrake and gearstick gaiters.
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Midlana1
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Re: Alfa powered build.

Postby Midlana1 » 01 Mar 2019, 17:12

You're making great progress.

ChrisS
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Re: Alfa powered build.

Postby ChrisS » 03 Mar 2019, 13:41

Almost there....just needs some attention from the angry grinder. At least the welds were running a bit smoother today - still ugly mind. Still no real idea why it was playing up so badly the other day.

tunnel cover almost done.jpeg




Oh, and I need to add a recess for the fuel pump 'crash' (inertia) switch that will live just in front of the gearstick.
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ChrisS
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Re: Alfa powered build.

Postby ChrisS » 14 Mar 2019, 14:45

Since my last post I've completed that tunnel cover and made a small start on the dash panel that sits in front of the passenger. I've also distracted myself with 3D printing and CAD (the computer sort, not cardboard).

A friend made me some indicator supports for those tiny LED jobs I posted about a while back. One thing led to another and I now have a printer (that arrived today and needs some new bearings due to transit damage) plus a copy of Fusion 360 with little clue how to use it. Have to say how impressed I am that Autodesk allow free use of the product for small business and hobbyist users. I got a totally free 'startup' licence with zero hassle and just a few mouse clicks. If I suddenly find myself earning big bucks from using Fusion(!) I'll be more than happy to pay the annual subscription. To be clear, there is NO chance that will ever happen!!

So, firstly the indicator supports:

indicator on stalk.jpeg


Can't recall if it is ABS or PLA. ABS I think but must check. The chap even did printed internal M6 threads for fixing it to the nosecone. As they are mostly a hollow honeycomb internal structure, they are remarkably light but still pretty tough. The inner and outer skins are solid. Only real issue is the surface finish...but I quite like it for some reason. Assuming it is ABS, it can be smoothed with acetone fume if I have a mind to. Or sanded, filled and painted.

The first job I have for my own printer (when the new parts arrive and I can finish assembling it) are some covers for the suspension mounts at the front. I need to make them present a larger radius than they currently do for the certification test it has to pass here. First idea was to use plastic nut covers plus a printed piece that covered all the edges, like this:

Cover Mk2 v3.png


Then I thought maybe I'd include the elements needed to cover the bolt head and nut:

Cover Mk3 v5.png


This is in two halves - you can just see the join line on the narrow section. I've included small holes for alignment dowels where the parts meet and the parts should be a tight press fit on the bolt head and nut.

Not so sure about these though, they look very bulky to me so I suspect I'll go with the less intrusive first version with separate nut covers.

Yes, I know, I found another displacement activity.
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freakynami
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Re: Alfa powered build.

Postby freakynami » 14 Mar 2019, 17:11

You've fallen into the wonderfully entertaining world that I've been avoiding with all of my strength - congratulations! I am very jealous...

I used to have access to a printer at work that I ran for the department, so I have designed and made a few car parts, I've likely forgotten most of the useful info, but here goes:

ABS will survive longer in a vehicle interior. PLA will creep and die after a season, sooner if outside, depending on what the component is doing.
I never printed ABS as I understood it required a heated bed and some sort of enclosure to control warpage of the base during initial layers.
I always re-designed a part and re-printed it, every. single. time. The second version was always much better.
You can print a tap drill size hole, then thread it with normal taps. Helicoils should work better again, but I've never tried it.
The slicer software can make a big impact on the part's properties.
Consider using a printed part as a step to the final part, using either lost PLA casting, or printing a mould for a fibreglass part. Best of both worlds with accurate tooling but tried and traditional fabrication material for the end part.
Do a lot of testing prints initially so you get a feel for the printer. There are a tonne on the net of various parts that have funky overhangs and features that will give you an idea of the limits for your designs.
Further to the testing, print some holes and pins, being aware of the direction of print with respect to the feature axis, and measure them. I found a rule of thumb to follow for good fitments with my designs was to allow something like 0.2mm additional clearance for all mating faces; after the print came out it was always slightly over - I guess these days it can be tweaked in the extruder ratio maybe? but I always had to make allowance of parts never fit together.
If your filament requires it, keep it in an air-tight container - I wasted hours of messing around trying to fault find bad prints before I tumbled to this - some have the issue, some don't.
Try all of the different bed preps people suggest - I used glue stick for ages, but finally gave hair spray a go and never went back; everyone seems to have a strong opinion on their favourite, try them all, mix it up for different fillament suppliers...

Have fun!


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