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Project M71

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Posts posted by Project M71

  1. Looking good...

    So the table has all all bolt hole and stud hole diameters and centres corrected to the Lotus drawing, main body inner bore increased from 125.00 to 126.00 (marked as non-critical) and all the lug ribs marked with * are increased in size for strength... The radius smoothing to reduce stress is very good and we don't need the second ABS/VSS sensor (just one with a threas tapped), or the casting turret! :)

    With reference to the earlier point on the bearing mounting tappings, I don't see a 6.0 hole, just "Bearing recess bore step" at 5.00, as on the Lotus drawing but this is the step change on the large recess dia, I presume. So what dia are the bolt holes on the Lotus drawing and is this used? 

  2. 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

     

  3. 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

  4. 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.
  5. 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

    IMG_1879_1024.jpg

    IMG_1877_1024.jpg

    IMG_1872_1024.jpg

    IMG_1871_1024.jpg

    IMG_1886_1024.jpg

    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 😄

     

     

    • Like 1
  6. Just commented this on social media but I thought I would add here...

    Here is a Play List for those interested in the process to part machining, once CAD is complete... CAM (Computer Aided Manufacturing), tool selection & tool paths, NC/G Code (on which the Millling machines/lathes directly operate) and then the actual machining https://youtube.com/playlist?list=PL2UIEWwqJXrORlKXRQjQHY4ESaQNZdQi3

    This process is all part of the setup costs that the estimates for the uprights include - and why costs reduce with greater part numbers, as the CAM only has to be done once

     

     

  7. On 04/04/2022 at 18:16, fjmuurling said:

    Just curious, (maybe @mike_sekinger knows) but are these dimensionwise the same as for a 1990 SE. (I know there are some extra holes for the ABS sensors and the webbing is a bit "wider" to accomodate the hole for the handbrake cable.

    More numbers means price reduction? Where is the sweet spot? 

     

    I'll let Mike comment/confirm, as I only concentrate on the Turbo Esprit and V8, but I don't see any changes in the model changes after the Commonisation of 'Eagle Chassis': May '89

    Here: http://www.projectm71.com/changes.htm

    The ABS sensor holes are there in the CAD model and the webbing is as on the V8

     

  8. On 05/04/2022 at 08:34, cweeden said:

    I have been plagued by delays (not related to the hub carriers) so they are not fitted at the moment but I have trial fitted them, which led to a couple of discoveries. We'd missed the ABS sensor hole and fixing bolt somehow, so I have had that machined. The other aspect that wasn't quite right was the diameter of the hole for the sliding bush in the lower mount, it has been machined a little larger than stock and so I've had to resort to using some shim steel to take up the slack. I'm pretty sure Ignas has corrected the model for both of these since we discovered them and we have the correct dimensions for everything now since Sacha shared the original drawings so easy enough to check. Unfortunately Ignas lost patience with me and we've had a falling out which is a shame but I would be very confident his model is good and as long as the machine shop does a proper job these will be very good. I can't remember the grade of alloy we went for though, I think it was 6061 but here is the advice from @CHANGES 6061 is where most start for this sort of application, preferably in T6 format .. (heat tempered) for maximum strength (6061-T6) You can also get it in a stress relieved form which has a suffix of 51 (6061-T651).

    I would imagine the sweet spot has been hit more or less, that pricing is very good indeed.

    @Project M71 are you planning on any surface treatment to prevent corrosion? (just curious), also where are you based?

    Based in Bucks, near West London

     

  9.  

    OK All.. I've been in conversation with Ignas and he is checking the revisions for the points below now and he is going to post the verified files for both sides on the Forum at the weekend

    1) larger lower mounting diameter

    2) ABS sensor and tapping

    The ABS sensor tapping may need to be added but he will do that

    I'm not sure if my efforts in learning CAD were warranted/worthwhile but if we get files for both handed parts, with the corrections, all ready for CNC and our group buy works out, I guess in some way they were.

     

     

  10. The first of the second round of quotes look much more promising (some of the original quotes were over £2,500 for a single unit) - the quote below for 10 off (5 pairs) is now at a single unit price of 607.45 Euros ($670.55, £511.40) 

    That sounds very, very good, for billet units that are many times stronger than the originals

    I am now obtaining CAD software to produce the other handed version and I will get final quotes for muliples of pairs, left and right uprights

    *** We then need at least 5 names of those intersted in a pair - I think we are near that with those here and others on social media - I will compile a full list ***

     

    HubsQuote10.jpg

  11. The second round of quotes are being prepared in order to bring costs down:

    Please note these responses sent to all those quoting:

    1.       When do you need an offer for? When must the parts arrive(Deadline)?
    ** No specific deadline but sensible delivery time

    2.       Will this be a one off order or long term? ( for our tooling up purposes )
    ** This would be an on-going order with a long lifetime, its a classic car part which the manufacturer no longer supplies and there are virtually no second hand parts available - there is a large car club community that are looking for a replacement

    3.       Please could you supply a current price per unit that we must beat?
    ** Sub £800 per unit - they would be ordered as a left and right hand pair, so sub £1600 total

    4.       Anything extra you’d like to highlight or I should know?
    ** Your company can be advertised on the car club forum and other websites without charge, if you can match the requirements

  12.  

    I now have the CAD file from Novorota, the company that was developing a CNC billet replacement for the Esprit V8 rear uprights...

    https://fb.watch/b7_C8hGMNY/

    Project M71 will use a pair of these but I'm also canvassing Interest in group buy - I will be contacting engineering companies for price estimates

    So let me know if you are interested

     

    Many Thanks to Ignas for providing the CAD data! 👍 His original thread: 

     

    122931703_106093361300691_4704791062328664618_n.png

  13. Speaking to Ignas, formerly of Novorota, for some time about getting Rear Uprights (hubs here) produced for Project M71 

    As known, the business is no longer in existence and they only produced one pair for a test installation - he is very busy on a new project with tight deadlines, working all hours of the day, so things are moving slowly but in his words he is "thinking about giving you and everyone else the files for free, they are CNC ready, and any modern shop wouldn't need anything else to make a pair"

    Let's hope this happens... and thinking ahead it would be an opportunity for the usual combining for a "club order", as I'm sure a machine shop would give favorable prices for a larger order

  14. Speaking to Ignas, formerly of Novorota, for some time about getting Rear Uprights (hubs here) produced for Project M71 

    As known, the business is no longer in existence and they only produced one pair for a test installation - he is very busy on a new project with tight deadlines, working all hours of the day, so things are moving slowly but in his words he is "thinking about giving you and everyone else the files for free, they are CNC ready, and any modern shop wouldn't need anything else to make a pair"

    Let's hope this happens... and thinking ahead it would be an opportunity for the usual combining for a "club order", as I'm sure a machine shop would give favorable prices for a larger order

    • Like 2
  15. Speaking to Ignas, formerly of Novorota, for some time about getting Rear Uprights (hubs here) produced for Project M71 

    As known, the business is no longer in existence and they only produced one pair for a test installation - he is very busy on a new project with tight deadlines, working all hours of the day, so things are moving slowly but in his words he is "thinking about giving you and everyone else the files for free, they are CNC ready, and any modern shop wouldn't need anything else to make a pair"

    Let's hope this happens... and thinking ahead it would be an opportunity for the usual combining for a "club order", as I'm sure a machine shop would give favorable prices for a larger order

    • Like 2
  16. Speaking to Ignas, formerly of Novorota, for some time about getting Rear Uprights (hubs here) produced for Project M71 

    As known, the business is no longer in existence and they only produced one pair for a test installation - he is very busy on a new project with tight deadlines, working all hours of the day, so things are moving slowly but in his words he is "thinking about giving you and everyone else the files for free, they are CNC ready, and any modern shop wouldn't need anything else to make a pair"

    Let's hope this happens... and thinking ahead it would be an opportunity for the usual combining for a "club order", as I'm sure a machine shop would give favorable prices for a larger order

  17. The key point in the cam fitting procedure appears to be the torquing of the camshaft pulley bolts to only 5 ft lbs with the clamping caps, belts and tensioners in place and then rotating the crank and the belts "dragging" the cam pulleys in this state (so the cam pulleys rotate with the light torque of the bolts to the cams held stationery by the clamping caps). This would keep positive tension on the belts and the cam pulleys, until ther bolts are torqued to 74 ft lbs, with the timing properly established at 10 deg BTDC:

    Marked in red:

    105939988_V8FittingCamshafts.thumb.jpg.c73b93e60ad4814906d36e5d8d234f2d.jpg

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