rash12
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posted on 28/10/17 at 11:11 AM |
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bits and bobs
1 pair rubber iva bonnet catches from car builder solutions Part Number: BNLCH £10 .00 inc postage
3 southco catches as per rs catalogue RS Stock No.245-5547 £10.00 for the three inc postage
1 pr front coil springs of a seven 1.9 id not sure of poundage 200mm long good condition black powder coat £16.00 inc postage
can provide pics if required all catches new in bags
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cfc999
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posted on 28/10/17 at 10:31 PM |
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1st dibs on the two types of catches please.
Will u2u tomoz.
Cheers
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rash12
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posted on 29/10/17 at 07:02 AM |
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Thanks no problem
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maurof74
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posted on 19/11/17 at 09:26 PM |
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hi,
could be interested in the springs if you are able to check poundage
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rash12
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posted on 20/11/17 at 02:43 PM |
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hi maurof74 not sure how I would do that but any suggestions welcome
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maurof74
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posted on 20/11/17 at 07:48 PM |
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If it is not possible to read the rate (typically written in the flat end of the coil), two methods are possible but it is not so simple to get
accurate results:
1)
In principle I can perform the calculation but to be accurate eough I need the following measures with the required accuracy:
1. Coil ID or OD with 0.5 mm accuracy
2. Wire diameter within 0,1mm accuracy
3. Number of turns (considering the portion of wire that is free from contacts, i.e. not the upper and lower flat part)
Even with these accuracy the approximation is roughtly +/- 20 lb/inch for typical coils. Most part of the error comes from wire diameter as the
stiffness is proportional to d^4.
2)
Alternatively you can make a test with known test load.
Cheers,
Mauro
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cliftyhanger
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posted on 20/11/17 at 08:05 PM |
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Indeed, just worked out some springs in my garage.
I grabbed an assistant (wife!)
Measured spring unloaded.
Weighed myself on bathroom scales (yikes, need to lose a few lbs)
Put a bit of wood on top of spring (easier to measure to) and stood on spring. Wife measured the loaded length.
In my case I am 170lb, and the spring compressed by 30mm
So, 25x170/30=141 lb/inch
Simple!
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rash12
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posted on 20/11/17 at 08:35 PM |
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number of turns is 8
od of coil is 70.10
diameter of coil is 10.75
is that all you need
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maurof74
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posted on 21/11/17 at 11:55 AM |
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81000 x pi/32 × 10,75^4 / (2 pi x 8 x ((70,10-10,75)/2)^3) = 80,8 N/mm = 461 lb/inch
Probably they are 450 or near.
7/100 mm less in wire diameter (e.g due to pai t tickness) are enough to justify the difference between 461 and 450.
For me are too stiff. I'm looking for 275 or near, but at least you have this estimation. I would be curious to see if the suggested experiment
will give the same...
Cheers
Mauro
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fregis
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posted on 27/11/17 at 06:44 PM |
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i think i take springs, looking 400-450
compare: i have 350, wire 10.4, so 10.75 will be near what i need
[Edited on 27/11/17 by fregis]
Never be afraid to do what you are insolvent, remember: amateurs built the ark - Professionals built the Titanic.
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