1997 Nuke Proof Reactor hardtail

[gis_guru]

I will get pictures and measurements for the badge as well. I will try to get them tonight but it being a typical bike shop the hours on the door are a general approximation not gospel so worst case it may be tomorrow before I get them.
Always glad to help. Would you be interested in recouping some of your expenses fabricating the fork braces? I need a pair and I would be more than willing to pay a share of the prototype cost and the cost of cnc'ing a second set. Let me know what you think.
Cheers

 

[syncrosfan]

"Would you be interested in recouping some of your expenses fabricating the fork braces? I need a pair and I would be more than willing to pay a share of the prototype cost and the cost of cnc'ing a second set. Let me know what you think."
No problem, I'll help you out on that one, you helped me out too. The only thing that would cost you is the CNC'ing cost, that's the one thing I have to outsource. The CAD I did myself and the rapid prototyping I'll do at work for free. As soon as I get the prototypes and the measurements from you I'll double check the data and send it off to the machinist. I'll get a quote from him, we'll need 6 of them braces, 2 for me, 2 for ishaw, 2 for you. i'll let you know what the cost of the parts will be beforehand. I'm thinking 7075 aluminum clear anodized. I wonder what aluminum grade the original linkages were...? I might have to make custom hardware too, specially the un-threaded shoulder spacer with flange, it's a really odd size and they don't make any hardware like the in that size, I looked into shoulder bolts as well but no luck to find any in 9mm diameter. Looks like a custom job again. Wonder if titanium would work as an axle for the roller bearings? The original stainless hardware is a tad heavy but then again Ti is kinda' soft so brinelling of the surface could be an issue... aside from cost.

 

[gis_guru]

Fantastic! That would be great. I think 7075 clear anodized would be the best as well. I dont know what they used for original parts but I know the hubs and bars that they made were mostly if not all 6061. I think ti would be ok unless you are going to put massive mileage on it, then you might start to have brinelling issues.

 

[syncrosfan]

I attached a cross-section dimensions shot so that you can get a better idea of the size.
I think Ti would work too, because I have a Hurrycat Vorace fork and the roller bearings run on custom Ti shoulder bolts without any visible problems.

 

[ishaw]

I'm still very impressed with your work, a great skill to have for sure. For the bolts, it could be possible to get bearing sleeves, as you could then use ti bolts, but with a harder wearing bearing surface. I looked into this briefly for my sts. It might mean the bolts are a little feeble though. Happy to look at options as I'll be looking for a full set of everything for the forks sadly, but those braces look great. On amp forks they have a head tube size cut out on a part of the cnc work, maybe if clearances are an issue this might be an idea?

 

[syncrosfan]

"On amp forks they have a head tube size cut out on a part of the cnc work, maybe if clearances are an issue this might be an idea?"
That's certainly the way to go if there's interference with the head-tube. We'll have to wait and see what gis_guru comes up with when he looks at his bike.
The bearing sleeves would be a good idea, mainly because you can buy them off the shelf and you can use regular bolt setup with them, a lot cheaper than custom machined parts. I'll have to look if INA have bearing sleeves to pair with their roller bearings.

 

[gis_guru]

He has some water issues at the shop so has closed early the last few days. I will get in bright and early Saturday morning and get the measurements and pictures of everything.

 

[gis_guru]

Re:

Here are the pictures. The cross piece is just a hair under .25" around 6.26 mm. The clearance of the upper is .75" and when the fork is compressed the upper actually gets further away. The lower is also around .75" and it stays at least that far away the issue I see with it is that when the lower compresses the lower linkages may hit the bridge although the L shape may help this. Look over the photos and let me know if you need more or other measurements.

Cheers
Chris

 

[syncrosfan]

How about the clearance between the cross bridge and the headtube? With 14mm at the lower L-shape we would be more than twice as wide as your current setup. Also, how tall is the brace? I've got 15 mm in the CAD now.
Thanks,
Raul

 

[syncrosfan]

Re:

I finally got all the rapid prototyping parts in order to mock-up the front end. From the measurements that gis-guru provided me and the mock-up I would say that the original cross braces are way too wimpy which probably contributes to the somewhat flexy feel in the front. This is all attributed to the fact that they wanted to use the same part for the upper and the lower brace and with the attempt of simplifying the machining they had to make the parts so thin in order to provide clearance to the upper brace. I'm thinking of making an upper and lower brace specifically for the intended clearances. They would look the same in most views but the back section through the middle would be different. It would make the machining of the upper brace a little more difficult but it would be manageable (one added step). The benefit would be a much stiffer cross brace and a stronger front end. I'm going to make version 2.0 of the linkages this week and get them printed again and do one final check on the clearances, the release the data to the milling guy. How about incorporating an engraved Nuke Proof logo on the front face of the braces?