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fender brace

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Re: fender brace

Postby Dr_Drache » Sun Aug 31, 2014 9:19 am

efcivic wrote:I am going to make some, maybe out of round tube or square , square is cheaper , or maybe that rectangle tubing as the one above. I'm just waiting on some flanges for the door plates and a machined part for the front hole. The way I did it though there is no flex in the mounting for the front hole like that big plate on the Nagisa so if the car is a little off then it might be an issue.


Image


Image


there is a few things wrong with your design (if indeed the photos is of yours)
it will be weak at the doors, and you have a single bolt for the front. the reason for the plate is to distribute the load over the sheetmetal.

also, top door bracket is impossible to install. the bottom may not be able to be installed as well. the design is top notch for looks, but is functionally flawed.
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Re: fender brace

Postby efcivic » Sun Aug 31, 2014 10:38 am

The top bracket is installed now with a nut and stud, the top tube of mine is angled for compression and is not in bending like all the other designs that have the tube going from the lower bolt angled up,my front mount is clamped with 4" long bolt and the the fitting that will be machined and welded to the brace takes the bolt out from being in a shear load to just clamping.

Image

Image
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Re: fender brace

Postby efcivic » Sun Aug 31, 2014 10:50 am

For the bottom plate I am using all cap screws and 1 stud for the top so there is plenty of room

Image
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Re: fender brace

Postby Dr_Drache » Sun Aug 31, 2014 10:52 am

so, your's is only useful for someone who has a welder?

I was pointing out simple design problems that are obvious, I am actually curious how these are being looked at and how a single bolt, welded is going to magically become a clamp load only and not a shear.

the angled for compression means nothing, when you have single shear points for everything. the basic design is nice, but seems it will only good, if it's welded onto the chassis. which makes the seemingly advanced design, no longer advanced.

the original questions were intended to bring up discussion.
I'm not trying to discredit your design, just some if it just will not work as it's currently laid out to us.
cap screws still need the same clearances as hexhead,
studs still need room for the nuts. something as strong as this should not have a single shear point, at least 2 bolts on the fender side.
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Re: fender brace

Postby efcivic » Sun Aug 31, 2014 11:23 am

Dr_Drache wrote:so, your's is only useful for someone who has a welder?

I was pointing out simple design problems that are obvious, I am actually curious how these are being looked at and how a single bolt, welded is going to magically become a clamp load only and not a shear.

the angled for compression means nothing, when you have single shear points for everything. the basic design is nice, but seems it will only good, if it's welded onto the chassis. which makes the seemingly advanced design, no longer advanced.

the original questions were intended to bring up discussion.



I don't think a a 2nd bolt that goes though 1 side of the .065 or thinner sheet metal does anything. Right now all the designs put the front bolts in shear because the bolt is the only thing holding the plate to the sheet metal, what happens when you take the bolts out or they get loose, does it just slide around on the plate? Just picture the aluminum piece above in steel and welded to the brace, even if you take the bolt out the brace will still work. As far as the mounting points for the plates in my opinion round tube weld 360 and inch or less away from the door bolts is stronger than a piece of 1/8" mystery metal welded at a 90 and a triangle gusset where ever it will clear. Also round tube can be gusseted too.
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Re: fender brace

Postby efcivic » Sun Aug 31, 2014 11:44 am

here is another made just to get the measurements so I could work on it off the car as I dont have a garage, this one you can use stock bolts

Image
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Re: fender brace

Postby Dr_Drache » Sun Aug 31, 2014 2:17 pm

efcivic wrote:
I don't think a a 2nd bolt that goes though 1 side of the .065 or thinner sheet metal does anything. Right now all the designs put the front bolts in shear because the bolt is the only thing holding the plate to the sheet metal, what happens when you take the bolts out or they get loose, does it just slide around on the plate? Just picture the aluminum piece above in steel and welded to the brace, even if you take the bolt out the brace will still work. As far as the mounting points for the plates in my opinion round tube weld 360 and inch or less away from the door bolts is stronger than a piece of 1/8" mystery metal welded at a 90 and a triangle gusset where ever it will clear. Also round tube can be gusseted too.


I'll take this slow,
yes, a plate with a 2nd bolt will make a HUGE difference, that's basic engineering (friction and clamp loads).

what happens when a bolt gets loose? REALLY? what happens when my door falls off from loose bolts, or my engine falls out of the bay? that's a silly way to look at things; it won't slide around, because you use round holes, not elongated holes.
bolts, attached with back plated nutserts; PROPERLY TORQUED done, next?

why would you ever take a bolt out of a brace then worry about it coming apart? ...wonder why my pulley came off, I took the bolt out.

I don't understand your rand about gusseting metal... 1/8" plate with mystery metal? I'm willing to bet it's steel, what grade? that's a good question, but irrelevant because, well steel is steel IN THIS CASE.

the mounting points for your tube testfit, are too damn close to the bolts, you wouldn't be able to install it, this photo you posted here :
efcivic wrote:Image


seems to have everything nearly perfect to your design, the structural are not too close to the mounting plates,
has the triangulation you are looking for...
you are using heavy plates on the door side, why are you so against a plate where it would actually make a huge difference?
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Re: fender brace

Postby Meech » Sun Aug 31, 2014 2:57 pm

Because he's trying to sell something attractive. He's already invested in this so it's understandable to try to justify the hard work.

I already have drawings, just need a welder. Actually, it'd be an honor if you were to go over my sketchings Doc. I could email them to you. Just PM me.
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Re: fender brace

Postby Dr_Drache » Sun Aug 31, 2014 3:09 pm

Meech wrote:Because he's trying to sell something attractive. He's already invested in this so it's understandable to try to justify the hard work.

I already have drawings, just need a welder. Actually, it'd be an honor if you were to go over my sketchings Doc. I could email them to you. Just PM me.


being attractive and being a great item, are not exclusive properties. he has something VERY nice going there. just a few tweaks and they are solid for anyone.

I'd be more than willing to look over your documents. I'm in the same boat, I can't weld (partly because no equipment, and partly it does take some artist skill and manual dexterity, that I'm low on)
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Re: fender brace

Postby Meech » Sun Aug 31, 2014 4:18 pm

As I said before, I can start popping these out right now, but, the negative idea people automatically have to flux core weld jobs is currently turning me off from starting. I've done work for others who trust me and the parts have held up. [crud], I welded a differential for a friend running a KA-T in his 240sx lol. I'm just trying to save up to afford a better welder before I start popping out pieces for big profit.
ebob wrote:Wish I aged as well the HF. I think I know why I lost 5mpg, my car's carrying and additional 150 pounds.

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Re: fender brace

Postby efcivic » Sun Aug 31, 2014 5:51 pm

Meech wrote:As I said before, I can start popping these out right now, but, the negative idea people automatically have to flux core weld jobs is currently turning me off from starting. I've done work for others who trust me and the parts have held up. [crud], I welded a differential for a friend running a KA-T in his 240sx lol. I'm just trying to save up to afford a better welder before I start popping out pieces for big profit.




You should make them now ,who cares if they are flux core, just use small c's (CCCC) and they will look amazing. Sell a couple for cheap and you got your money for a new machine that takes gas.
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Re: fender brace

Postby tommy » Tue Sep 02, 2014 7:51 am

Picked up mine over the weekend; with the powdercoating, look real Purdy! :lol:

Will have pics and measurements shortly.
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Re: fender brace

Postby Dr_Drache » Tue Sep 02, 2014 8:03 am

tommy wrote:Picked up mine over the weekend; with the powdercoating, look real Purdy! :lol:

Will have pics and measurements shortly.


[crud], I owe you something...
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Re: fender brace

Postby tommy » Fri Sep 12, 2014 9:02 am

Image

Image

Couple of pics of the powdercoated braces - sorry for the blurriness, camera was running out of juice. I'll take better ones soon.

Doc - what I'll do is take some outlines on paper of them and send them along with your door lock stickers - that way you'll have exact dimensions.
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Re: fender brace

Postby Dr_Drache » Fri Sep 12, 2014 9:17 am

tommy wrote:Image

Image

Couple of pics of the powdercoated braces - sorry for the blurriness, camera was running out of juice. I'll take better ones soon.

Doc - what I'll do is take some outlines on paper of them and send them along with your door lock stickers - that way you'll have exact dimensions.


sounds like a plan sir!
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Re: fender brace

Postby vanrij » Thu Sep 18, 2014 4:42 am

I think have these ^ same braces. I thought I noticed added stiffness in the corners particularly under heavy braking. Although I might have been wanting to feel benefits after buying them. Might reinstall them and attempt before and after flex measurements :D Maybe a thin layer of machinist's dye underneath alternating finger-tight mounting bolts or an arm attached to the opposing plane situated to scratch the dye...hmmm.

I also wonder if aluminum might be preferable considering the ability of a more ridged metal (6000-7000 series maybe?) to resist movements caused by chassis flex. In addition to weighing less (my steel units are surprisingly heavy,) aluminum may be less of a compromise to the OEM crumply zone design (shearing vs. bending - but still adding some level of support if forced to move a distance more than the effective range of a brace in the event of a crash. Not sure about that one, might have to bust out the FEA. It would be more expensive and difficult to cut/weld and might just crack, so feel free to ignore. :lol: Just thinking out loud as the interest is still there.
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Re: fender brace

Postby tommy » Thu Sep 18, 2014 12:08 pm

That's an interesting thought, though I wonder how good our originally-designed crumple zones would do against a 2 ton + SUV, no matter what was there for bracing. I think we'd be legless regardless of material. :nod:
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Re: fender brace

Postby EF RaceRR » Wed Sep 24, 2014 9:22 pm

budget_crx wrote:
EF RaceRR wrote:I don't think he will need longer bolts.


I did when I installed mine, the factory bolts did not thread in as much as they should. You could probably get away without doing so but keep in mind those bolts are supporting your heavy doors and the braces take away about a 1/4in of thread.


Interesting. I didn't need longer bolts when I installed mine. Everything was fine.
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Re: fender brace

Postby CBURKE » Fri Sep 26, 2014 1:27 pm

tommy wrote:Image

Image

Couple of pics of the powdercoated braces - sorry for the blurriness, camera was running out of juice. I'll take better ones soon.

Doc - what I'll do is take some outlines on paper of them and send them along with your door lock stickers - that way you'll have exact dimensions.


How are these bolted on?
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Re: fender brace

Postby tommy » Fri Sep 26, 2014 2:00 pm

With bolts. :greenbanana:

Look at the previous page; there's a pic which shows it clearly.
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Re: fender brace

Postby CBURKE » Fri Sep 26, 2014 2:42 pm

Smart ass! :biggrin: :P

lol no I get that, but I also know there's not threaded holes there. Do you slide a bolt in there from the back somehow?
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Re: fender brace

Postby CBURKE » Fri Sep 26, 2014 2:45 pm

tommy wrote:Image


Never mind, I see now :-)b
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Re: fender brace

Postby tommy » Fri Sep 26, 2014 3:01 pm

Yep, sorry - could have given you a clearer answer the first time. :wink:
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Re: fender brace

Postby CBURKE » Fri Sep 26, 2014 3:13 pm

lol it's cool. Can you take a picture of the other bracket that goes on the inside?
Does anyone know if these really do what they say?

When I think about it, it bolts to the outer skin, that's like 18-16 gauge steel. Can't imagine that would be very strong.
My idea is to run a sleeve through the hole that goes into the bay, then bolt it on from there.

I think a good test would be is to jack up the car, put it on jack stands and let it down. Measure the front from nose to ground. Then put the fender brace on and do it again, see how much, if any, it changes. I would think it would help it not flex as much... I could be WAY off on this anyway.....
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Re: fender brace

Postby Dr_Drache » Fri Sep 26, 2014 3:51 pm

CBURKE wrote:lol it's cool. Can you take a picture of the other bracket that goes on the inside?
Does anyone know if these really do what they say?

When I think about it, it bolts to the outer skin, that's like 18-16 gauge steel. Can't imagine that would be very strong.
My idea is to run a sleeve through the hole that goes into the bay, then bolt it on from there.

I think a good test would be is to jack up the car, put it on jack stands and let it down. Measure the front from nose to ground. Then put the fender brace on and do it again, see how much, if any, it changes. I would think it would help it not flex as much... I could be WAY off on this anyway.....


it works 100%. I've mentioned this to you already I think. when people think "it's only bolted to sheet" you have to think, it's not just shear you are working with, you also get strength from clamping forces and because of multiple bolts, the clamping and shear compliment each other, and increase the total strength of the joint.

proper clamp loads using multiple fasteners (with washers and/or backplates) can get you really close to the strength of MIG welds on sheet.
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