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Post by coopdad on Jan 15, 2009 9:19:04 GMT -8
Hey Richard O, I was toying with making my own leaf springs using your tutorial and wanted to ask how bouncy your springs are? Are they pretty stiff? (for those that are new here: public.fotki.com/modeljeeper/models/working_leaf_suspension/here is his tutorial) Has anyone here tried it using brass instead of styrene? I seem to recall someone making leaf springs out of brass but don't know where I saw it. I am concerned about strength of this shackle and its mount also. John
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Post by modeljeeper on Jan 15, 2009 14:07:03 GMT -8
First of all, my CJ-7 that's been sitting for 7+ years on the styrene leaf springs, has not had any failures (other than during a move across the country). The only issue I have had was the rear quarter-elliptical springs sagged a bit. I have periodically re-arranged the Jeep so the wheels flex in a different position, yet it will still sit flat. I would not recommend playing with the model everyday as the plastic will wear out and fail. (I admit to jumping the RockToy a few times on the work bench and it worked great ;D ) When you place the curl into the strip plastic, it becomes very 'bouncy' and depending on the thickness of the material, they will hold their shape very well. Also the amount pressure placed on the strip when curling will affect the 'bounce' (greater arc=more 'bounce'). I started with 'HO scale' Evergreen strip (scale 2x8; .022x.090inch; 0,6x2,3mm) and have used other dimensional strips depending on the weight of the model (.020x.080inch; 0,50x2,0mm) or (.020x.100inch; 0,50x2,5mm). www.evergreenscalemodels.comJust like the real 1:1 world, the number of leaves and the length of each leaf will affect the ‘bounce’ of the spring pack. Also, ensure there is enough added length to the main leaf (and subsequent leaves) to account for the amount of ‘curl’ and added lift height. I also believe only gluing/securing each leaf together at the axle centerline will let each leaf work separately when ‘flexing’ and work together when ‘stuffing’ the wheel. Do NOT glue the leaves entirely together! I tried brass before, however it was too stiff and would not flex under just the weight of the plastic model. I have not tried Plastruct’s gray ABS or white styrene yet, www.plastruct.com/Pages/Catalog.html nor have I tried the suggestion to glue two-thinner strips together once curled to assist with keeping their shape. As far as the chassis mounts, I’ve just build them following 1:1 techniques, either plate plastic on the sides of the frame or tubes securely ‘welded’ in place of the kit’s mounting locations. All of my shackles consist of three pieces of plastic, two sides and the center spacer. These are ‘welded’ with typical styrene glue, Ambroid Prowled is my preferred choice. www.ambroid.com/Ambroid.html Hopefully this clarifies some of the questions not addressed in the original tutorial. Richard O. modeljeeper
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Post by coopdad on Jan 16, 2009 5:14:24 GMT -8
Richard, your info will be a great help. My big concern is not really how "bouncy" it is (poor choice of words), I should have said "soft". In my last build the rear suspension had no lift so I just used the stiff stock spring. With this one there will be a mild lift so I will have to make the spring. If (when) I make the spring I want to be sure I have control where the tire ultimately sits in the wheel well. Don't want to spend all that time only to have it sag too far. John
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Post by modeljeeper on Jan 16, 2009 9:22:54 GMT -8
IF you want working leaf springs, then keep the leaves unglued. Otherwise, glue them together in a pack and they shouldn't sag at all. Again, ensure there is adequate length added to the leaf pack for the lift and/or add more leaves to the pack. I have not had any of my working full leaf springs sag, yet, but make sure you have compensated for the weight of the completed vehicle with accessories when constructing the springs and locating the wheel. Just like the 1:1 world, they will settle under the weight of the vehicle.
On either of your Bronco projects, there should not be alot of weight in the rear (minimal body, no interior, few accessories) but it will be affected by the weight in the front.
For your application, I'd just glue the individual leaves into a soild pack. Richard O. modeljeeper
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Post by coopdad on Jan 16, 2009 19:22:12 GMT -8
I will, thanks for the expertise! John
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