Coilover Shocks - Build your own

Chassis and suspension of whatever design

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Re: Coilover Shocks - Build your own

Postby Wynand on Tue May 01, 2012 7:43 pm

Garreth, Im just an amateur with a lathe trying to save a buck and I believe there are many more capable persons on the board that can give you much better advice, but I will give you a few tips that work.

First of all your tip must be grind to 60 degree for metric thread. Very important to set the toolpost at 29.5 degrees to material and align the cutting tool perpendicular to workpiece. When the feed is engaged, it will cause the bit to cut on the leading edge and trailing edge free - much cleaner cut and less stress on tool-bit than having both sides of tip cutting simultaneously causing rough cut and even breaking tool-tip.
Although this is very amateurish, ignore the thread dial gauge and best NOT to disengage the feed at the end of cut, rather reverse after taking bit off thread and when ready for next cut, feed a bit more, forward the feed and presto, automatically picks up the thread again - do same until thread is finished. Rather have a few runs than trying to cut to deep at a go. I used 140 rpm for cutting the threads.

For nuts I threaded a long piece of ally enough for four nuts., machined the collar to align/hold spring, marked (grooved) the adjusting pegs centerline, and part off, and repeat procedure for other nuts.

I also planned to use Mini shocks but the distance between the shock brackets centres on my chassis at ride height is 330mm and still need travel for bumps - the Beetle ones are 390mm extended and at ride height about smack in the middle of shock travel 8)

I have also designed for the use of locking C-rings, is there any reason in particular you haven't gone this route?


I assume you are talking about Cir-clips or snap-rings. To use that one need to cut a groove at least 0.80mm deep and the Gabriel shock casing wall thickness is only 1.0mm thick, and to top it, not always perfect round to groove. Thus my reason to form roll a groove for ally locking shells - much larger contact area and therefor much stronger.
Last edited by Wynand on Thu May 03, 2012 1:05 pm, edited 1 time in total.
Wynand
Webpage: http://5psi.net
Car: McSorley 442E chassis
2.0l Ford Pinto with ZX9 bike carbs
Lightened flywheel, camjob, 4-2-1 exh
5 Speed Ford type 9 g/box
IRS - 3.7:1 diff ratio
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Re: Coilover Shocks - Build your own

Postby ross on Wed May 02, 2012 7:50 am

Hi Gareth,
Google "thread cutting in a lathe" you'll be directed to lots of sites, mainly amature but in credibly informative. One of my favourites is www.gadgetbuilder.com.
Locost chassis with Toyota 20 valve blacktop and T50 box.
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Re: Coilover Shocks - Build your own

Postby Garreth on Wed May 02, 2012 8:50 am

Thanks for the help :)
I am in a lecture right now haha so will look I into it tonight.

Cheers
Completed 1.6L 20V ST
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Re: Coilover Shocks - Build your own

Postby Wynand on Thu May 03, 2012 1:01 pm

With the poor service from the local spring agent in town, I cancelled my order and contacted a spring manufacturer in Boksburg directly and was quoted R125 ex Vat for a 250lbs/inch spring with 215 free length and 60mm ID. The rear springs are same but with 190lbs/inch ratio and cost R110 ex Vat totaling R535 incl. Needless to say I ordered.
This now brought down the cost for the complete set of coilovers to just R1785 all inclusive 8)

Ordered gold anodizing dye (mine disappeared :? ) to anodise the ally on the shocks (cadmium appearance)and when I receive this, I will post pics of the process and end results. Anyone can do this at home and it a simple process - more about this when I post the results.
Wynand
Webpage: http://5psi.net
Car: McSorley 442E chassis
2.0l Ford Pinto with ZX9 bike carbs
Lightened flywheel, camjob, 4-2-1 exh
5 Speed Ford type 9 g/box
IRS - 3.7:1 diff ratio
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Re: Coilover Shocks - Build your own

Postby ross on Fri May 04, 2012 1:30 pm

I've started collecting kit for ahome anodising set up; What are you using as the Cathode and what kind of power supply?
Locost chassis with Toyota 20 valve blacktop and T50 box.
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Re: Coilover Shocks - Build your own

Postby Wynand on Fri May 04, 2012 5:39 pm

ross wrote:I've started collecting kit for ahome anodising set up; What are you using as the Cathode and what kind of power supply?


Ross, if I may, here are a few pointers and mixes about anodising.

But first, all/most electroplating are done with 5-7vdc and the positive terminal goes to the sacrificial anode and the negative to the part (cathode). The anode is the same material as the plating bath, eg, tin anode for tin plating etc. Chrome (nasty stuff) is a process after nickle plating has been done and the anode there is lead because that is the only material that will last in that poisonous bath.

However, you are keen on anodising and here is the basics of it.
Anodising is best done with a current of about 19-21vdc BUT the part become the anode. The negative goes to a lead cathode simply because that is also the only material that will last in the sulfuric acid solution bath. Take note, the lead cathode area must be bigger than the parts to be plated and the more parts - or bigger - the more juice (amps) it want...
Many DIY guys use a 12vdc car battery to good effect but only good for smaller parts. Plating or anodising need a smooth and stable supply of current for best results. My transformer and diodes (rectifiers) are ex mining loco stuff and rated well over 350 amps continuous :twisted:

If you have not anodised before, may I take liberty to give you some bath formulas and procedures to follow.
But, remember AAA - always adds acid to water and not the otherway around! Always use only distilled water - tap water contains chemicals that causes problems. Never touch parts with bare hands after cleaning started.

Steps:
1. Cleaning / etching using a caustic soda wash (500g caustic soda to 5lt distilled water) @ 38C. Dip only 1 - 3 minutes because this stuff dissolves ally!

2. Clean in cold distilled water (dip few times)

3. Desmut: ally will be dark after etching and this are the other alloys in it causing that. Mix desmut bath - 20% Nitric acid to distilled water mix, iow, 1lt Nitric acid to 5lt distilled water. Dip parts in this bath at about 30 - 35C degrees temp for anything between 3 - 10 minutes until clean. Repeat if necessary.

4. Clean in cold Distilled water by dipping. 2 x

5. Fun part - anodising: Here I use two baths, one for GP natural anodising and one for dyed anodising.
a) GP natural anodising bath: 33% Sulfuric (battery) acid ratio to distilled water solution @ 20 - 25C temp
b) Colour anodising bath: 50% Sulfuric acid ratio to distilled water solution @ 20 - 25C temp.

To anodise:

Natural finish - immerse parts into 33% solution bath (use ally wire to suspend parts) and connect positive to parts hanger support and connect negative to the lead cathode. Switch on power. The period depends on thickness of anodising needed and one must be careful when screw thread are present like in coilovers adjuster sleeve and nut. Usually about 2-3 minute per micron coating and 7 - 10 minutes ample for shock parts.
I use supple air agitation in my bath that results in better finish but this is optional.

6. Rinse in cold water and boil parts for about 30 minutes and you done.

Coloured Anodising: Same procedure as above but using the 50% solution bath.
However, it is best to get the parts as fast as possible into the dye solution after the anodising rinse (no boiling/sealing at this stage). Keep immersed in dye solution for about 5-15 minutes - depending on the depth of colour you want.

7. Rinse part and hang to dry - some commercial dyes no not need to be sealed after rinse, but some dyes need to be boiled for about 30 minutes after rinsing from dye solution.

And thats it. Give me a PM and I will supply you the contact number in JHB where you can get any colour quality dye.

For cheaper parts and to help buddies, you can use a good quality organic clothes dye but this do not have the same quality of finish as the better commercial ones. If you go for these dyes, experiment which make gives best results and these have to be boiled sealed as explained.

I hope this is helpful to you and perhaps others that want to do the same.

Warning; acids are dangerous and always wears full PPE and eye protection when using this. Strong solution of baking soda in water is a good neutralizing agent should these acids get into contact with you or clothing - always keep a mix on hand :)
Wynand
Webpage: http://5psi.net
Car: McSorley 442E chassis
2.0l Ford Pinto with ZX9 bike carbs
Lightened flywheel, camjob, 4-2-1 exh
5 Speed Ford type 9 g/box
IRS - 3.7:1 diff ratio
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Re: Coilover Shocks - Build your own

Postby andersonhdj on Fri May 04, 2012 6:12 pm

Just to add to Wynands safety info, Sodium hydroxide ( caustic soda) is as dangerous as acid perhaps even more so!
Keep a bottle of vinegar handy, it's strong enough to neutralise yet not have serious adverse affects to your person.
I've seen a mans cleansuit burned right off him from sodium hydroxide, not fun!

Sorry fella's just one other thing, been away from pharma for a while now, slipping!!

When cleaning / pickling your ally in sodium hydroxide, the gas that comes off is HYDROGEN, it is explosive in concentration so DO NOT SMOKE and do this with adequate ventilation
Hamish.
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Re: Coilover Shocks - Build your own

Postby ross on Sat May 05, 2012 11:22 am

Great information guys, thanks a lot. I'm familiar with the process on an industrial level, spent many years in aerospace development and manufacture; but I've never tried it on a small diy scale. I also worked in a battery factory (lead acid) lots of nasty stuff there. One of my other interets is air rifles, that's wher i would use he anodising for custom part. The forum's been a bit dead for a while, glad to see interest again, there's a huge fund of knowledge out there amongst the members. thanks again.
Locost chassis with Toyota 20 valve blacktop and T50 box.
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Re: Coilover Shocks - Build your own

Postby Wynand on Mon May 14, 2012 7:32 pm

Here is the finale to my coil over shock project. 8)

I anodised the ally parts today and since my planting plant table with baths is covered with board and a pile of stripped down engine over it, I did it the anodising in some plastic buckets, much to the annoyance of the missus - pinched it from her kitchen. Luckily I still had access to the caustic soda bath for cleaning and that made thing a little wee easier.

I first decided to have the parts anodised gold but changed my mind and went to something very different. The final finish is a satin like gold/cadmium finish that looks great and much better than shiny gold - in my view that is :wink:
The way I achieved the desired effect was; I followed the normal anodising procedure, etch, rinse, desmut, rinse, anodising (10 minutes) rinse. Then I only dipped the parts into the gold dye (Sanodal Gold 4N dye) for just about 3 seconds and dip straight into the boiling water to seal, but also add a very little dye to the sealing bath itself and boil away for about 20 minutes to seal and it gets this soft golden sheen colour.

The final cost of my four coil overs - some changes after earlier posts:
I originally bought 2 Gabriel oil filled shocks and later 2 gas filled ones which I plan to use for the conversion - I paid for these two gas filled ones R370 and last week when I bought another pair to keep it all gas, found out my supplier screwed himself and this pair then cost me R506. I will keep the two oil filled shocks for spares....

Shocks - four off: R876
Materials - ally: R507
Springs - 4 off: R400 (cash, no invoice asked)
Dye - 100gram: R50 (The solution can last for years and still have enough to last a lifetime)
Total cost R1833 for four gas filled adjustable coilovers complete 8)

Here are some pics of the anodising and end results

This is the caustic soda bath to clean and etch - note the "boiling" of the parts
Image

Here are the desmut bath (left bucket) and the anodising bath. I use a little air agitation whilst anodising. In the back under the plating plant is my power supply, tapped at 18vdc for this.
Image

The following two pictures are of some parts completed and anodised. The round switch I made (brake bias bar adjuster) and the little half shell locking halves are still in natural bare aluminium for comparison
Image
Image

Here is a complete coilover shock with spring.
Image

and finally, the first coilover fitted at last...it appears silver because of the flash reflection of camera. Here is the reason why I did not fitted the threaded sleeve right to the bottom of the shock. The upper wishbone fitment with shock and the angle of the shock call for this amount of clearance to fit and operate safely.
Image
Last edited by Wynand on Mon May 14, 2012 7:53 pm, edited 1 time in total.
Wynand
Webpage: http://5psi.net
Car: McSorley 442E chassis
2.0l Ford Pinto with ZX9 bike carbs
Lightened flywheel, camjob, 4-2-1 exh
5 Speed Ford type 9 g/box
IRS - 3.7:1 diff ratio
User avatar
Wynand
 
Posts: 148
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Location: Welkom

Re: Coilover Shocks - Build your own

Postby Garreth on Mon May 14, 2012 7:40 pm

Awesome work!! :mrgreen:
Completed 1.6L 20V ST
Designing Ariel Atom Clone
http://www.garrethslotus.tumblr.com
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