MarkD
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 posted on 16/4/02 at 11:26 PM |
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Differences between the book, McSorley book chassis plans and cutting guide spreadsheet.
I just collected my RHS tubing and was about to start cutting the parts out using the excellent McSorley book chassis PDF plan dimensions
(http://mcsorley.net/locost/drawings.htm) but have noticed several differences between the book (2nd edition) and the McSorley plans. To make matters
worse I was also using a cutting guide spreadsheet that differs slightly from the book as well.
(http://www.esbconsult.com.au/ogden/locost/mirror/fstdcutlist.htm According to the file properties was written by someone called Rory Perrett)
Below is a summary of the main differences. Some are just a few millimetres so I’m guessing that what Ron meant by “leaving just minimal filling for
truing up”, but some of the difference are a bit larger.
G1 & G2. Book & Cutting Guide = 688mm. McSorley 686mm
J1 & J2, Book & Cutting Guide = 1476mm. McSorley 1472mm
K3 & K4, Book & Cutting Guide = 508mm. McSorley 512mm
LA & LB, Book & Cutting Guide = 330mm. McSorley 341mm (Looking at page 49 in the book I think the book is wrong)
N1 & N2, Book & Cutting Guide = 688mm. McSorley 691mm
O1 & O2, Book & Cutting Guide = 406mm. McSorley 478mm
O3, Book & McSorley = 965mm. Cutting Guide 1016mm
V, Book & McSorley = 965mm. Cutting Guide 1067mm
W1 & W2, Book & Cutting Guide = 635mm. McSorley 638mm
Y, Book = 813mm. Cutting Guide = 1067mm. McSorley 914mm (Looking at page 51 McSorley & Cutting Guide look incorrect.)
As anyone actually made a chassis using the McSorley pdf plans and did they have any problems following the dimensions? (I notice that Jim McSorley
is a locostbuiders member as well, but is building a non-book chassis. Thanks for making the plans available Jim – I don’t mean to be too
critical!)
Mark
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UncleFista
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| posted on 17/4/02 at 09:11 AM |
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No help from me I'm afraid 
Just posting to say Rory Perret is the secretary of the locost car club, cracking chap, bought a 4-2-1 crossflow manifold and a set of motorcraft rear
shoes for £14 from him a couple of weeks ago...
Sorry I couldn't be of more help ;(
Tony Bond (Unc)
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JohnFol
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| posted on 17/4/02 at 10:19 AM |
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I got the metal supplied cut according to the book, however the book has inaccuracies in it.
For example, lenght C (which is not on your list) is about 10mm too short. Also, G1 and G2 vary along C depending on engine so their lengths will
change. What was annoying is the book text explicitly states the lengths for the Ford 1300 engine, but the diagram shows the positioning for
non-Ford.
I guess that the list you have may be based on his experience, but as you say, a few mil is not a problem.
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James
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| posted on 18/4/02 at 09:16 PM |
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quote:
For example, lenght C (which is not on your list) is about 10mm too short.
Oh nuts! I cut my metal (including C) Monday night and fitted them to the jig tonight- and I've got a nasty feeling you're right. But hey- atleast
it's made me realise I marked up the jig wrongly anyway!
Could someone else confirm this before I go and change my gig too much. Also, are there any other rails that are wrong that I need to know about just
to get the basic chassis (main area of 25mm tube) done.
Any help appreciated!
Thanks,
James
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MarkD
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| posted on 18/4/02 at 10:39 PM |
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JohnFol
According to the book, McSorley plans and the cutting guide, C is the same length as Q.... so if C is too short does this mean Q is as well?
I suppose the best method is to cut the parts as I need them rather than in advance? It's a shame because my garage is full up with the Escort shell
and I thought pre-cutting the chassis parts would keep me occupied until I manage to get it shifted.
Mark
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David Jenkins
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| posted on 19/4/02 at 07:27 AM |
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quote:
I suppose the best method is to cut the parts as I need them rather than in advance?
I would always recommend fitting pieces as and when you need them, just to be sure.
You could always rough-cut the pieces with a bit of spare metal - a "fitting allowance".
David
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Dunc
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| posted on 19/4/02 at 07:27 AM |
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Get the exact measurements and angles for all tubes, cut all the tubes in one go, and assembly is a doddle. Just watch where you tack though, ie so
that you don't have to grind so you can fit H and FU1 & 2. Don't leave a mm or 2 to grind off, this is a nightmare, you think it's not much but it
is very difficult to keep the cut square.
Dunc.
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David Jenkins
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| posted on 19/4/02 at 07:46 AM |
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quote:
Don't leave a mm or 2 to grind off, this is a nightmare, you think it's not much but it is very difficult to keep the cut square.
GRIND?! If you've only got 1 or 2 mm to get rid of, a 12" bastard hand file* will shift it in about 20 seconds - and it's easy to keep it square,
with a bit of practice.
I did my entire chassis with hacksaws and files, and don't consider it to have been hard work. I didn't want to use a grinder as I would have got
grit all over my machine tools (also, I did a lot of my cutting in the late evening, so I didn't want screaming machinery at 11:00pm).
David
* to quote an old, old joke:
mechanic: "pass me that file..."
assistant: "do you want the round bastard, or the flat f*cker?"
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James
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| posted on 19/4/02 at 09:22 AM |
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quote:
quote:
I suppose the best method is to cut the parts as I need them rather than in advance?
I would always recommend fitting pieces as and when you need them, just to be sure.
That seems like a good plan- but you need at least some form/structure to the chassis before you can measure up the correct lengths of rails.
I have to admit I took a gamble and assumed that all the rails for the bottom section of the chassis (that goes on the gig) were correct in the book-
if you don't have them correct you've got very little against which to measure up the rest of the rails.
Damn you Champion. I don't need this stress!
Do you think if we wrote to Heynes they might supply an amendment to the book?
Somehow I can't see it but just a thought.
James
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JohnFol
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| posted on 19/4/02 at 09:29 AM |
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I've certainly wasted money having paid someone to make the cuts as per the book.
N1 and N2 need a 40 degree cut, but it's not shown.
The uprights of La Lb Lc Ld (can't remember which) are about 8 mil too short, but you can use C to make 2 new ones, as C is about 10 mil too
short.
Perhaps the £250 is a challenge, rather than an estimate 
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Nigel Kemp
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 posted on 25/4/02 at 06:30 AM |
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I'm not sure about the book corrections you're asking about, but check out an Australian site by Greg Rowell, for other apparent corrections...
http://members.ozemail.com.au/~rowellg/Pages/correct.htm
... also check out his main page (http://members.ozemail.com.au/~rowellg) for some photos of a true blue ozzie locost!!!
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prensel
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| posted on 25/4/02 at 05:39 PM |
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I only cut when i need it. The book has a lot of errors. 1" is 25.4 mm, we only get 25 mm rhs here so almost every tube length is wrong.
I made a triangular jig (2 * rhs 75mm sections of 3 meters each) so i never get a 'twisted' frame. I made it rotateble so i can weld and twist and
shuffle all night long 
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phil m
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| posted on 25/4/02 at 10:22 PM |
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McSorley info is good, as you can print off info on each piece with angles for each given accurately. As others have said it does pay to cut and align
(without welding) to make sure that everything fits
I'd like to see the biceps on the man with the file !!
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jbmcsorley
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| posted on 29/4/02 at 09:42 PM |
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Cheers all...
I appreciate the feedback on my CAD drawings... constructive critisism is always encouraged.
Just so you know how those drawings were derived... I did everything in standard inches and then asked the computer to apply metric measures as a
secondary dimension in the drawings.
I chose this approach for two reasons: 1) I plan to build with inches since all my tooling is standard measure, and 2) I had to decide early on which
unit of measure appeared to be more accurate from the book. Since the book design had so many exact inch figures (25" here, 42" there, etc.) I
assumed that the original design was done in inches. It only made sense to try and keep the units of measure the same as the original design so my
model would line up with the book as much as possible.
The internal rounding of inches to metric is precise since it was done by the computer... but any marksman will tell you that precision and accuracy
aren't the same thing.
I do hope the drawings don't cause anyone too much grief... but I've not heard of any errors so far. Then again, I've also not had anyone tell me
that they actually built from the drawings yet.... and yes... I'm planning a custom build where only few book dimensions apply (latest work in
progress 3D model was posted over the weekend BTW).
Again, thanks for the input.
-Jim M.
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David Jenkins
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| posted on 30/4/02 at 07:50 AM |
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quote:
Since the book design had so many exact inch figures (25" here, 42" there, etc.) I assumed that the original design was done in
inches
It's funny - I always had a theory that the car was originally designed in metric (it was a school project in its early days, and UK schools only
teach metric).
This theory is based on the fact that more metric dimensions are correct than imperial. I always figured that many errors were due to conversion!
David
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JohnFol
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| posted on 30/4/02 at 07:58 AM |
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I remember being in the 1st year that my school taught in metric. My brother was the year above and had to convert.
I'm 34, so if the book is in the 60's then it will be imperial
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David Jenkins
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| posted on 30/4/02 at 08:09 AM |
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Ron's version isn't that old - don't forget, he built it for his son within the last 10 years.
(Now the original design - that's another matter.)
David
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jbmcsorley
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| posted on 30/4/02 at 01:39 PM |
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I hadn't considered the impact of the school system on Ron's book... that would definetly explain why the metric measures in the book are more
accurate; While the initial measures may have been standard (off of the Westfield), most of the builds used as examples for the book would have been
done in metric and the numbers would have been validated time and time again.
One other factor is based on knowing what Westfield used for their original design to sufficiently satisfy the court's mandate of being different
from a true Seven. In otherwords, what unit of measure did Westfield choose when designing this chassis?
Seeing as how so many of the "critical" tubes are measured in exact inches (A1, B1 for instance), I think it would be too much of a coincidence to
have designed the Westfield in metric. And I don't know my UK history as I should, but at the time the Westfield was designed (and by whom we can
only guess)... would they have defaulted to standard or metric?
Anyway... regardless of the Westfield design... what I realized last night having given it more thought is that most of the angles and final lengths
in my CAD model are the derivative of laying out the "critical" tubes and then using an CAD approach known as "extrude to surface". This is, in
effect, the opposite of "grind to fit"... it is more like a "grow to fit" that can only be accomplished in a CAD environment.
The reason I mention this is because the angles and lengths derived in CAD are the result of asking the computer to determine the final length on most
of the tubes given certain contraints (usually outer edge alignment or meeting at a vertex, etc). While it might be precise, the accuracy of such a
method is based on the accuracy of the initial or most critical tubes used in the layout. I would consider A,B,C,E & K to be the most critical tubes
in the whole layout (geometrically, not structurally). Everything else in in one way or another driven by the length and/or angle of those tubes.
While the computer may be precise, the accuracy of the model is still driven by human input; the length of the critical tubes. Again, seeing as how
most of the critical tube lengths are exact standard measures (whole inches), I could only assume that standard measure would be the most accurate way
to start.
Ah yes... but then the real gotcha; working with 25mm tube instead of 25.4 mm tube can have a big impact over all and I think this is where a metric
builder will detect errors in my drawings. All of the tubes in my CAD drawings are a full 1"... or 25.4 even though the metric measures are rounded
to exactly 25 in the drawing dimensions. So you can see that anywhere that the thickness of the tubing effects the overall length, the metric
measures will be off by .4 and sometimes .8 of a millimeter. This is definetly compounded even more over the entire chassis.
Perhaps I should rework my CAD drawings in pure metric with exactly 25mm tube?  Sorry mates... unless someone is wanting to finance that
endeavor, I'm afraid the idea is going to have to wait.
Sorry for the long, theory filled post... as you can see, I greatly enjoy the subject.
Cheers,
-Jim M.
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Dunc
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| posted on 30/4/02 at 02:07 PM |
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Jim,
I know what you're talking about, I encountered the same problems doing my cad models. You have to define what you are going to use as your main
unit, decide what the main driving dimensions are for the tubes then take a leap of faith. Then there's the rounding problem. But I doubt any of us
are able to cut all the tubes to exactly the exact dimensions and ±1mm on all dimensions is more believeable and attainable.
Can't remember what your using to create the model but it seems you create the datums then the tubes from those. I used Proe and modelled each tube,
to the book initially, then assembled them into an assembly as you would do in real life. This can also be another source of errors. Can you export
your model in step or iges for a comparison to my model, I would be happy to do the same.
PS. I felt it better to move E and FU forward by a few mm so that the nuts for the suspension brackets would fit better. I felt that they would hang
too much of the LA and FU too much and didn't look quite right. Did you pay much attention to this?
Dunc.
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jbmcsorley
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| posted on 30/4/02 at 05:39 PM |
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Hi Dunc,
I'm also using a parametric, feature based modeling package (of questionable origin so I shouldn't name it directly ).
I used the same approach as you, but I was careful to crate each piece as cross-section that is blind extruded to both sides leaving the origin of the
part in the middle with an over all length similiar to the book. At this point however I didn't introduce any cut angles or additional features on
the ends of the tube unless the angle was critical to the defining the layout (like K1/2 must have 40 degrees on one end and 50 on the other).
I then created mating contraints in the assembly like you would in the real world (same as you). I used edges and vertices quite often which makes
compound angles rather easy. The last step however is unique... As each part was fully constrained, I switched the definition of the extrusion from
blind to 'up to surface'. This allows for very dynamic revision of the model without worring about loosing the face or edge used in the contraint
definition. It also 'cuts' the part with compound angles an to exactly the needed length automatically.
The great thing about this approach is that I can change a few critical parts and the whole model is revised automatically. It plays off the
parametric nature of a feature based model... but I didn't have to key in the parameters (I didn't use equations for instance)... it only relies on
the dependencies & contraints.
I haven't considered moving E or FU1/2 laterally... only transversly. And I haven't given much thought the the bolt clearance issue either. It
seems that the issue only exists on the rear lower wishbone mount... all others have plenty of clearance. As for how much the brackets overhang LA
and FU... I haven't focused on that part yet... thanks for the heads up.
I think I can send you IGES files... but I'm not sure if I have to export each individual part with the assembly, or if exporting just the assembly
will take care of business. There are nearly 50 part files and it might be a bugger.
I'll try to email you directly and we'll see how it goes. I can import Pro/E seamlessly... that would be cool.
Cheers,
jim m.
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Dunc
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| posted on 30/4/02 at 09:13 PM |
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With ProE you can create relations, layouts and skeleton models. Thinking back this was the way to. I did use the skeleton models for the suspension
geometry though, very useful feature.
You say you can read ProE models ok, would you prefer I just sent the ProE models, 2001 version, in a zip file or would you prefer a shrinkwrap in
Iges format, 1 part as opposed to many that the iges recognises.
Dunc.
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dexteria
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| posted on 26/5/02 at 03:08 PM |
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Hi Dunc,
Would it be possible for you to send me the CAD models in ProE format for the chassis and pinto engine.
Many Thanks
Mark S
dexteria@clara.co.uk
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XenoDraken
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| posted on 5/6/02 at 05:48 PM |
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Well I intend to build the McSorley 7+4 chassis. I'm sure somebody has done it allready, but if not I guess I will be the first??? Hehe, I keep
wanting to call my project the McSorley 7 now  . Dont want to get anybody in trouble though. I will still get the book of course, but when that
brass plate gets made for my dash, you can be sure the McSorley name will be there. No, I'm not related nor do I work for this fellow, but after
what I have retrieved from his website I think the credit is well justified! Mr. Champion certainly deserves just as much credit as im sure most of
you master builders see him as "The Man".
The point of my message, be it in the wrong place perhaps, is its nice to see that there are still lots of people out there that share knowledge for
the love of the hobby above the all mighty buck hehehe.
I can finally make my childhood dream come true
Mike Larsen
Ontario, Canada
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interestedparty
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| posted on 5/6/02 at 07:20 PM |
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I'm building a McSorley 442, that's the one that's 4 inches longer(2"in the engine compartment 2" in the tapered part of the cockpit) 4 inches
wider and 2 inches higher. I've added another 2 inches in the streaight part of the cockpit because I am 6'4". I am using Jim's previous design
before he modified it to suit a standard nosecone because I am fitting a Rover V8 and need the extra little bit of width. Lolocost do nosecones up to
3inches wider than standard so I should be OK.
Previously I was building my own design for Jaguar components but decided to abandon it as the Jaguar bits are just so heavy.
I am hoping to try an RV8 engine and gearbox in the chassis this week. Looks OK apart from the alternator. I see the Dax demonstrator uses a small
aftermarket unit mounted higher and closer to the engine centreline
Thanks, Jim, great work!, and I love that animated chassis on your web site. I might paint mine those colours
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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john_s
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| posted on 5/6/02 at 08:17 PM |
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I'm already planning a mk2 locost with a V8. i'll be interested to hear how the engine fits when you've tried it.
John
--
John Singleton
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