Canvassing Interest in group buy for Esprit V8 CNC billet rear uprights (hub carriers)

[mike_sekinger]

I`m happy to act as a funnel.  You can PM me and I will channel those.

[Project M71]

For reference, here are quotes I had for pricing for 5 units for the ver 1.3 file and it's mirror, without tappings, in 6061, from xometry

inbound1886336722.pdfinbound304828966.pdf

Edited April 13, 2022 by Project M71

[tmusc]

Is version 1.3 the final corrected version? I was going to get a price to make them here in Canada for the group. However, if there are changes to be made I will wait before I send it to the machine shop.

[cweeden]

7 hours ago, sailorbob said:

Yes, when comparing the CAD file to a hub carrier there are unfortunately some concerning discrepancies. Rather than clutter this thread with items spotted is there an alternative way to compile and coordinate this?

I'd rather you cluttered this thread so we can all learn, I am keen to know what discrepancies you've spotted. 

cheers

-Chris

[Project M71]

Ver 1.4 is the latest so far but this will need updating

 

[sailorbob]

As Mike has kindly offered to coordinate any comments it is probably best to let him disclose them in this thread (if he wants to).

[cweeden]

@mike_sekingercan you share them please?

[mike_sekinger]

@cweeden  I`ll share a complete list of all differences and observations, once the comparisions between the v1.4 CAD model, OEM upright and drawings have been made.

I guess that your prototype billet uprights were made in-line with the v1.3 model?

[cweeden]

Yesterday I finally managed to fit the prototype pair that Ignas had machined. I had to have the ABS/speed sensor hole machined and the relief's added for the two bolts that attach the trailing arm. I've also had to shim the sliding bush with some shim steel since the hole on these were 0.1mm diameter too large, we figured that out when the drawings surfaced. I can't quite remember if anything else was done but I don't think so, apart from them being anodised which I am aware will have reduced their strength a fraction.

I know Ignas has been waiting for this moment for a long time and so I want to apologise to him for the time taken.

Naturally I am very interested to learn what other points are raised.

cheers

-Chris

[mike_sekinger]

Hi Chris, that is hugely encouraging.  To have a confirmation that the physical fit works. 

Some of the differences are tolerance oriented where others are just optimisation/simplification for the CAM process.

Quite a lot of folks these days have adjustable upper and lower links,  so further fine adjustments are in any case possible.

[tomcattom]

Hubs are look good @cweeden

That's a familiar looking ABS sensor 🙂

6 hours ago, cweeden said:

Looking at the part numbers these appear to be the same part for the S4s (anyone correct me if I'm wrong), so given the encouraging signs from Chris I'd be interested in a set for mine, depending upon time scales - looking to do my suspension overhaul this coming winter.

[Chillidoggy]

Just a thought - given the history of lower lug breakages, has any attempt been made to strengthen up the new design in that respect?

[Project M71]

10 hours ago, cweeden said:

Yesterday I finally managed to fit the prototype pair that Ignas had machined. I had to have the ABS/speed sensor hole machined and the relief's added for the two bolts that attach the trailing arm. I've also had to shim the sliding bush with some shim steel since the hole on these were 0.1mm diameter too large, we figured that out when the drawings surfaced. I can't quite remember if anything else was done but I don't think so, apart from them being anodised which I am aware will have reduced their strength a fraction.

I know Ignas has been waiting for this moment for a long time and so I want to apologise to him for the time taken.

Naturally I am very interested to learn what other points are raised.

cheers

-Chris

Chis/Mike,

Yes indeed, this is very good to see

I am so glad to see this project come back to life - it was sorely needed and it's looking like the results will be excellent 😄

 

 

[Project M71]

The billet parts will of course be stronger but this comment on social media is very relevant:

Jonathan Edwards

I'd look at the mode of failure and re-inforce that area (probably the lower link legs, that's where 2 of mine cracked).

If you billet machine this you're paying for the part and the swarf, and the machine time so it makes sense to reduce as much as possible, plus a direct copy of a sand cast item isn't always ideal when you use different manufacturing methods.

[Project M71]

On 13/04/2022 at 13:04, sailorbob said:

Thanks for posting the files.

One item stands out, the tap drill size for the bearing mounting M7 x 1.0 mm thread is shown as 6.1 mm but for aluminium the general rule is to subtract the pitch from the diameter of the thread, i.e. it should be a 6.0 mm hole.

 

Good spot - my chart agrees

Drill-and-tap-chart-MEFexport.com_.pdf

[sailorbob]

Ian, the ribs of both the lower and upper lugs are thinner than the OE casting and are not tapered so they do not thicken closer to the body. Without some high mileage road testing or finite element analysis of the stresses to see if these thinner ribs are equal or stronger than the OE casting I personally would not want to risk using them on my vehicle.

[Project M71]

9 hours ago, sailorbob said:

Ian, the ribs of both the lower and upper lugs are thinner than the OE casting and are not tapered so they do not thicken closer to the body. Without some high mileage road testing or finite element analysis of the stresses to see if these thinner ribs are equal or stronger than the OE casting I personally would not want to risk using them on my vehicle.

 

How much thinner are they? I'll measure on my CAD and compare to my OEM parts

Finite element analysis would be good to put some figures on stress/relative strength but billet material is a lot stronger than cast - here are the numbers for Tensile and shear strength for 6060-T6 and A350.0-T6 sand cast (what material is the OEM part cast in exac

A356.0-T6 Sand Cast

Tensile Strength, Yield

>= 165 MPa @Strain 0.200 %

>= 24000 psi @Strain 0.200 %   Tensile Strength, Ultimate  >= 234 MPa >= 34000 psi

Shear Strength

143 MPa

20700 psi

 

6061-T6

Tensile Strength, Yield  276 MPa 40000 psi

Tensile Strength, Ultimate

310 MPa

45000 psi

Shear Strength

207 MPa

30000 psi

 

[mike_sekinger]

The brief for the re-work of the design has several objectives.   It is not an exercise to create an exact copy of the OEM upright.

The Lotus drawing is now with the engineering company and they will assess where simplifications for CAM can be made, whilst designing in some addtional strength for those acknowledged areas of weakness in the cast part.  The final item will be made from 6082-T6, where quotes for the billet material is already in progress.

More info to follow.

[cweeden]

Ignas did run some analysis with 'greatly increased loads' (I don't know what unless it's obvious from the pictures), needed to show some stress. To be fair I don't think the standard carriers fail in normal operation (but I could be wrong) it's mainly failures when removing seized lower mounting hardware.

cheers

-Chris

[mike_sekinger]

Time for an update on this mini-Project

We now have an Engineering/Manufacturing partner in the form of Aira Technology in the UK.  This company was co-founded by Alex Adamou, who some of you may know is the proud owner of a `99 Esprit V8.  Alex and his colleagues have a rich background in Aerospace and high level Motorsport, so the design and realisation is in good hands.

Aira Technology

Aira have been looking over the existing CAD and original Lotus drawings and have worked up a pricing offer for the V8 uprights.  We are also fortunate that JAE Parts have committed to an initial number of pairs in order to help get the project kick-started.

As a result, JAE will act as sole distrubutor for the USA.  US based individuals who want these billet uprights should contact Joe at JAE Parts.

The non-US pricing is the same for RH and LH uprights.  These will be manufactured in 6082-T6 and the price includes hard anodising:

Price each    -     935,00 GBP + VAT (or  1125,00€)

Costs for shipping and any local import duties are of course the responsibilty of the Buyer.   Prices in other currencies can be requested from Aira as necessary.

Once the CAD design is finalised, details of the will be shared on the optimisations undertaken.  A 3D printed prototype will be prepared and installed to confirm form and fit, prior to cutting of billet.

In the meantime, I would invite those people who are still keen to confirm their interest.   Billet material is being ordered on the basis of 10 pairs, so please react if you want to be in the first round of manufacturing.   

Finally, I would also ask that you funnel any questions via me, as I have agreed to act as the channel to Aira.  This will avoid them being overwhelmed by individual queries and allow them to focus on the design work at hand.

Regards,

Mike S

[mike_sekinger]

1-5. JAE Parts

6. Mike Sekinger

7. John Clark

8. Greg Dollimore

9. ..

10. ..

[David H]

22 hours ago, mike_sekinger said:

Time for an update on this mini-Project

We now have an Engineering/Manufacturing partner in the form of Aira Technology in the UK.  This company was co-founded by Alex Adamou, who some of you may know is the proud owner of a `99 Esprit V8.  Alex and his colleagues have a rich background in Aerospace and high level Motorsport, so the design and realisation is in good hands.

Aira Technology

Aira have been looking over the existing CAD and original Lotus drawings and have worked up a pricing offer for the V8 uprights.  We are also fortunate that JAE Parts have committed to an initial number of pairs in order to help get the project kick-started.

As a result, JAE will act as sole distrubutor for the USA.  US based individuals who want these billet uprights should contact Joe at JAE Parts.

The non-US pricing is the same for RH and LH uprights.  These will be manufactured in 6082-T6 and the price includes hard anodising:

Price each    -     935,00 GBP + VAT (or  1125,00€)

Costs for shipping and any local import duties are of course the responsibilty of the Buyer.   Prices in other currencies can be requested from Aira as necessary.

Once the CAD design is finalised, details of the will be shared on the optimisations undertaken.  A 3D printed prototype will be prepared and installed to confirm form and fit, prior to cutting of billet.

In the meantime, I would invite those people who are still keen to confirm their interest.   Billet material is being ordered on the basis of 10 pairs, so please react if you want to be in the first round of manufacturing.   

Finally, I would also ask that you funnel any questions via me, as I have agreed to act as the channel to Aira.  This will avoid them being overwhelmed by individual queries and allow them to focus on the design work at hand.

Regards,

Mike S

Hi Mike, I'll definitely be up for a pair after testing, please put my name on the list (1998 V8). Thanks David

[mike_sekinger]

1-5. JAE Parts

6. Mike Sekinger

7. John Clark

8. Greg Dollimore

9. David Harris

10. ..

Only one space left on the first run of 10-off pairs.

[fjmuurling]

If all the testing etc goes right I'm in for my SE

@mike_sekinger

[mike_sekinger]

1-5. JAE Parts

6. Mike Sekinger

7. John Clark

8. Greg Dollimore

9. David Harris

10. Freek Muurling

All 10 slots for the 1st run of production are filled.  Thanks Gents !

Once the design is complete a list of corrections and enhancements will be shared.  Once the 3D printed model has been fitted and confirmed, then the design will be "signed-off" and production will be ready.   At that point, the balance of the pro-forma invoice will be due.

More info to follow.