Engineering a better harness bar (warning: long…)
#102
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ColdFeet, Teknics, Murphy and Prophet7000,
Based on your comments here, I took the liberty of adding you to an "interested" list on the thread in the GB section. Hope that was OK.
https://www.rx7club.com/showthread.p...33#post7074733
Based on your comments here, I took the liberty of adding you to an "interested" list on the thread in the GB section. Hope that was OK.
https://www.rx7club.com/showthread.p...33#post7074733
#103
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ColdFeet, Teknics, Murphy and Prophet7000,
Based on your comments here, I took the liberty of adding you to an "interested" list on the thread in the GB section. Hope that was OK.
https://www.rx7club.com/showthread.p...33#post7074733
Based on your comments here, I took the liberty of adding you to an "interested" list on the thread in the GB section. Hope that was OK.
https://www.rx7club.com/showthread.p...33#post7074733
-Rob
#104
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Thought some people would like to see a more up-to-date CAD image of the current design.
This new shock tower mounts decrease setup and programming of the CNC. This reduces cost significantly and is the reason that I can set the selling price at, or under $400 (prior to this design revision, selling price would need to be in excess of $550 in order for me to break even).
In order to facilitate this type of design, I had to change the mounting configuration to bolts placed in single-shear (rather than double as before). In order to compensate for this, I am now using much larger 5/8" Grade 8 bolts. The larger bolts are much more resistant to shear and any bending effects.
The end result is a design that is actually much stronger than before. Sometimes its actually a good thing to be forced to make design changes (in this case, due to excess cost). It offers you the opportunity to look at the product from a different angle, and find improvements that you may not have otherwise.
The prototype will be based on this design configuration.
-Rob
This new shock tower mounts decrease setup and programming of the CNC. This reduces cost significantly and is the reason that I can set the selling price at, or under $400 (prior to this design revision, selling price would need to be in excess of $550 in order for me to break even).
In order to facilitate this type of design, I had to change the mounting configuration to bolts placed in single-shear (rather than double as before). In order to compensate for this, I am now using much larger 5/8" Grade 8 bolts. The larger bolts are much more resistant to shear and any bending effects.
The end result is a design that is actually much stronger than before. Sometimes its actually a good thing to be forced to make design changes (in this case, due to excess cost). It offers you the opportunity to look at the product from a different angle, and find improvements that you may not have otherwise.
The prototype will be based on this design configuration.
-Rob
#105
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Good News
After working with some of the local machinists, I am now extremely confident (like 99.99%) that I can keep the selling price slightly UNDER $400. I'm now shooting for $375 (including shipping). I know, I know. 375 is not really a dramatic difference from 400. However, there were more than a few people who said 400 would be their cutoff, so maybe this will help them out a bit.
Of course, actual pricing will be determined in a few more weeks once I have the prototype in hand, and I have the chance to iron out some details. You'll have more details on this when I get closer to production.
One of the details that I'm still working on is the final finish. My original plan was to offer the bar in a brushed finish, and allow for anodizing as an added-cost option for those who wanted it.
Now, I'm seriously considering just anodizing everything black for the standard package. Customers could still specify if they want a different finish.
Any inputs as to the finish of the bar and end brackets?
-Rob
Of course, actual pricing will be determined in a few more weeks once I have the prototype in hand, and I have the chance to iron out some details. You'll have more details on this when I get closer to production.
One of the details that I'm still working on is the final finish. My original plan was to offer the bar in a brushed finish, and allow for anodizing as an added-cost option for those who wanted it.
Now, I'm seriously considering just anodizing everything black for the standard package. Customers could still specify if they want a different finish.
Any inputs as to the finish of the bar and end brackets?
-Rob
#107
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It might be cool to have it in red to match the front R1 bar. No thoughts on having an RX-7 plate like the front R1? Also I vote for having the cargo divider parts. And will the stock strut tower bar covers still fit over these?
#108
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Its possible, but I think it might be a little over the top for the rear bar, considering it's basically in the interior of the car. A black piece would give a more subtle look. Of course, if enough people have interest....
Yep, I thought about it. Even talked to some local laser etchers to see what type of plate I could have made up. I personally think that the added cost is not worth it for the rear bar. Still may be something that I do for the front bar, when I build that though...
Are you talking about the mounts for the hatch cover? This will be offered as an added-cost option. The reason its an option is that there are many people who don't use the hatch cover, and I don't feel they should have to pay for something that they won't use.
Yep!
-Rob
No thoughts on having an RX-7 plate like the front R1?
Also I vote for having the cargo divider parts.
And will the stock strut tower bar covers still fit over these?
-Rob
#109
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Yep, I thought about it. Even talked to some local laser etchers to see what type of plate I could have made up. I personally think that the added cost is not worth it for the rear bar. Still may be something that I do for the front bar, when I build that though...
Are you talking about the mounts for the hatch cover? This will be offered as an added-cost option. The reason its an option is that there are many people who don't use the hatch cover, and I don't feel they should have to pay for something that they won't use.
Yep!
#110
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No more inputs as to the finish of the bar?
The more I think about it, the more I'd like to anodize everything. This would provide a nice durable finish, and give it a classy look. Of course, I think I'm just a big fan of the anodized aluminum look, which is probably the real reason I'm leaning that direction. Probably will end up doing the rear bar in black, but clear is another possibility.
On a side note, I ordered most of the hardware that will be needed. The 5/8 button-head bolts used to secure the bar to the mounting brackets are simply MASSIVE. The head is 1" in diameter Yet, everything should still fit in the space constraints that I've designed for.
I think the machinist is beginning to get annoyed, as I keep asking when the prototype will be finished...
-Rob
The more I think about it, the more I'd like to anodize everything. This would provide a nice durable finish, and give it a classy look. Of course, I think I'm just a big fan of the anodized aluminum look, which is probably the real reason I'm leaning that direction. Probably will end up doing the rear bar in black, but clear is another possibility.
On a side note, I ordered most of the hardware that will be needed. The 5/8 button-head bolts used to secure the bar to the mounting brackets are simply MASSIVE. The head is 1" in diameter Yet, everything should still fit in the space constraints that I've designed for.
I think the machinist is beginning to get annoyed, as I keep asking when the prototype will be finished...
-Rob
#111
Full Member
iTrader: (4)
End brackets black.
No opinion on the bar - though, if you went black then you could etch RX-7 right into the bar. Very cool imho
Probably would want the mounts for the hatch cover (gotta use that $25 you saved us somehow). Depending how the look turns out - why would we want to swap it in and out?
No opinion on the bar - though, if you went black then you could etch RX-7 right into the bar. Very cool imho
Probably would want the mounts for the hatch cover (gotta use that $25 you saved us somehow). Depending how the look turns out - why would we want to swap it in and out?
#112
Perpetual Project
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No more inputs as to the finish of the bar?
The more I think about it, the more I'd like to anodize everything. This would provide a nice durable finish, and give it a classy look. Of course, I think I'm just a big fan of the anodized aluminum look, which is probably the real reason I'm leaning that direction. Probably will end up doing the rear bar in black, but clear is another possibility.
On a side note, I ordered most of the hardware that will be needed. The 5/8 button-head bolts used to secure the bar to the mounting brackets are simply MASSIVE. The head is 1" in diameter Yet, everything should still fit in the space constraints that I've designed for.
I think the machinist is beginning to get annoyed, as I keep asking when the prototype will be finished...
-Rob
The more I think about it, the more I'd like to anodize everything. This would provide a nice durable finish, and give it a classy look. Of course, I think I'm just a big fan of the anodized aluminum look, which is probably the real reason I'm leaning that direction. Probably will end up doing the rear bar in black, but clear is another possibility.
On a side note, I ordered most of the hardware that will be needed. The 5/8 button-head bolts used to secure the bar to the mounting brackets are simply MASSIVE. The head is 1" in diameter Yet, everything should still fit in the space constraints that I've designed for.
I think the machinist is beginning to get annoyed, as I keep asking when the prototype will be finished...
-Rob
I would actually like an anodized MATT light/medium grey, if it has to be anodized; something between raw aluminum and a dark grey (exactly as it appears in your illustration, at least how it looks on my monitor). I've seen anodized parts that have a satin/matt sheen too it; maybe they sandblast it first? That would look great, very functional and business-like.
I realize the need to standardize coors to minimize cost, but could you ask the vendor how much it would be for a one-off color (if nobody else wants this)?
BTW, how much do you anticipate the cargo cover mounting option to be?
Thanks!
Daniel
#113
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Looks really good so far!
I would actually like an anodized MATT light/medium grey, if it has to be anodized; something between raw aluminum and a dark grey (exactly as it appears in your illustration, at least how it looks on my monitor). I've seen anodized parts that have a satin/matt sheen too it; maybe they sandblast it first? That would look great, very functional and business-like.
I realize the need to standardize coors to minimize cost, but could you ask the vendor how much it would be for a one-off color (if nobody else wants this)?
BTW, how much do you anticipate the cargo cover mounting option to be?
Thanks!
Daniel
I would actually like an anodized MATT light/medium grey, if it has to be anodized; something between raw aluminum and a dark grey (exactly as it appears in your illustration, at least how it looks on my monitor). I've seen anodized parts that have a satin/matt sheen too it; maybe they sandblast it first? That would look great, very functional and business-like.
I realize the need to standardize coors to minimize cost, but could you ask the vendor how much it would be for a one-off color (if nobody else wants this)?
BTW, how much do you anticipate the cargo cover mounting option to be?
Thanks!
Daniel
Really don't have a clue about the price for the cargo cover mount yet, as I'm still pursuing a few different options. Some of these options are less expensive than others. Personally, I want to make it out of machined aluminum. But of course, this is a more expensive option. Whatever happens, I'll make sure that it stays within a reasonable price range ($20-40).
-Rob
#114
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Also just wanted to post a quick update on the prototype manufacturing:
My machinist fell ill last week, and got behind on a few of his projects. The completion date for the prototype has been pushed back to the 19th. So apparently I still have another week to twiddle my thumbs.
-Rob
My machinist fell ill last week, and got behind on a few of his projects. The completion date for the prototype has been pushed back to the 19th. So apparently I still have another week to twiddle my thumbs.
-Rob
#116
A deep brushed finish that is hard anodized black would look very nice back there.. Just enough to say look at me, but still not so much stand out to take over the back of the car.. I like so far, can't wait for the protype shots.
#118
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-Rob
#123
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Update
Recently received the prototype. I'm currently in the process of testing, and verifying the design.
Hopefully, I'll post another update complete with pictures on Monday. Stay tuned...
-Rob
#124
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UPDATE – Harness bar progress
Well, I would have posted this update a few days ago, but I’ve been a little preoccupied, and the forum apparently was down for a couple days last week. Bottom line is that I’m ready to initiate a group buy, and start accepting orders. But due to the transfer of ownership, I’m having a little trouble getting the necessary permission to formally advertise. But rest assured I’m working on it.
Anyway, I received the prototype a week and a half ago, and have been busy conducting some analysis on it. Overall, I’m extremely happy and confident with the design. Everything is functioning exactly as intended. The fit is exceptional, and the shoulder harnesses work perfectly. As expected, there a few minor design revisions I will make, but nothing that would be noticed. I used it at an auto-x event this past weekend and it worked great! This is definitely a perfect device for those who do auto-x and occasional track events.
Here are some pictures showing the main components that will comprise the basic kit for $375: Included will be the two machined mounting brackets, the central bar, and Grade-8 hardware, along with shipping anywhere in the continental US. Obviously the bar and mounting brackets in these photos are in a raw-machined finish. The actual production version will be anodized black. For at least the initial group buy, I will provide an added-cost option for custom anodized colors. I will also have a no-cost option for sending the components in an unfinished state (tumbled and media-blasted to remove machining marks). This will be offered for those customers that want to do their own custom finishing other than anodizing (i.e. polishing, painting, powdercoating, etc).
Assembled components:
Here’s a closer picture showing the mounting connection. Grade 8, 5/8” button-head bolts are used to secure the bar to the mounting brackets.
This shows a comparison picture between the M8 mounting bolts used in both the stock shock-tower bar, and the Rotary Extreme harness bar, and the 5/8” button-head used in my design. I shouldn’t have to tell you which one is which.
The following series of pictures show the bar installed in the car:
Details showing the installed bar with shoulder harnesses attached:
Lastly, another comment on additional options.
There will be an added-cost option for custom built hatch cover mounts. I do not have a prototype in hand, but they basically consist of precision-bent aluminum rod, machined to work with this bar. The standard finish for these will be the same black anodizing. This option will go for $35.
There will also be an option for some different quick-release pins as shown below. These feature a Grade-8 Stainless shaft and internal mechanism, and an anodized aluminum head. These provide for an even easier method of securing the harness straps, and will compliment the bar nicely. Unfortunately, they cost right around $20 each, so expect this option to run you $80 is you want a set of 4.
That's all the updates I have for now. Let me know what you guys think, or if you have any questions.
-Rob
Anyway, I received the prototype a week and a half ago, and have been busy conducting some analysis on it. Overall, I’m extremely happy and confident with the design. Everything is functioning exactly as intended. The fit is exceptional, and the shoulder harnesses work perfectly. As expected, there a few minor design revisions I will make, but nothing that would be noticed. I used it at an auto-x event this past weekend and it worked great! This is definitely a perfect device for those who do auto-x and occasional track events.
Here are some pictures showing the main components that will comprise the basic kit for $375: Included will be the two machined mounting brackets, the central bar, and Grade-8 hardware, along with shipping anywhere in the continental US. Obviously the bar and mounting brackets in these photos are in a raw-machined finish. The actual production version will be anodized black. For at least the initial group buy, I will provide an added-cost option for custom anodized colors. I will also have a no-cost option for sending the components in an unfinished state (tumbled and media-blasted to remove machining marks). This will be offered for those customers that want to do their own custom finishing other than anodizing (i.e. polishing, painting, powdercoating, etc).
Assembled components:
Here’s a closer picture showing the mounting connection. Grade 8, 5/8” button-head bolts are used to secure the bar to the mounting brackets.
This shows a comparison picture between the M8 mounting bolts used in both the stock shock-tower bar, and the Rotary Extreme harness bar, and the 5/8” button-head used in my design. I shouldn’t have to tell you which one is which.
The following series of pictures show the bar installed in the car:
Details showing the installed bar with shoulder harnesses attached:
Lastly, another comment on additional options.
There will be an added-cost option for custom built hatch cover mounts. I do not have a prototype in hand, but they basically consist of precision-bent aluminum rod, machined to work with this bar. The standard finish for these will be the same black anodizing. This option will go for $35.
There will also be an option for some different quick-release pins as shown below. These feature a Grade-8 Stainless shaft and internal mechanism, and an anodized aluminum head. These provide for an even easier method of securing the harness straps, and will compliment the bar nicely. Unfortunately, they cost right around $20 each, so expect this option to run you $80 is you want a set of 4.
That's all the updates I have for now. Let me know what you guys think, or if you have any questions.
-Rob
Last edited by saxyman990; 07-29-07 at 08:17 PM.