Need some small tubes machined

[jmw19]

Please note, these are shock spacers for a mountain bike, but this board seems to have a lot more machinists than the cycling board I frequent.

That said, I want to fit a new rear shock, and the spacers are either out of stock or fairly expensive for what they are. I'd rather pay someone here to make them - I'm happy to cover materials and time, but would like to keep it under $30.

The dimensions are all metric, and most aren't critical. The pieces I need are basically hollow axles, with spacer collars for each side, to hold the shock in alignment with the frame and swingarm. The axles should have decent wear resistance, so a steel or stainless steel would be preferred, but the collars aren't stressed, so pretty much any aluminum alloy is fine.

Here's the dimensions:
1 22mm long, 12.00mm OD, 8mm ID in steel or SS
1 42mm long, 12.00mm OD, 6mm ID in steel or SS
2 4.7mm long, 16mm OD, 12mm ID in Al
2 14.7mm long, 16mm OD, 12mm ID in Al

I live in Central PA, for shipping considerations. My PM inbox is clear, so let's get the bids flowing and get me back on the trails.
Thanks in advance,
Jon

 

[gadget_lover]

I'm not offering to do it. I seldom do steel and don't have a lot in my stockpile but....

It helps if you specify which dimensions can be bigger or smaller. I suspect the first one is a minumum of 8mm id, but we don't know how much bigger can it be.

Daniel

 

[modamag]

Jon, which bike forum do you belong to?

 

[jmw19]

Jon, which bike forum do you belong to?

I'm on MTBR.com mostly, and the sister site RoadBikereview.com. I mostly lurk and read the reviews (kind of like CPF...), though I was fairly active back when I raced - 7 years ago, where does the time go?

gadget_lover, pardon the lack of tolerances - it's been a long time since I've drawn up any mechanical plans. The inner diameters of the 22 and 42mm tubes can be a tenth off pretty easily - preferably smaller, as I can bore them out if necessary. I just can't machine the whole thing. The outer diameter is the most important - they'll be fitting into metal-backed polymer bushings with a 12.00mm inner diameter, and a tight fit is important. I'd say a hundredth either way would be okay.

The pairs of shorter tubes should be a slip fit on the 12mm OD tubes above. The length isn't critical, but a bit long is preferable. The outer diameter could vary by a millimeter - it's the least important measurement.

I can sketch up and post a drawing with dimensions and tolerances if it would be helpful.
Best,
Jon

 

[PhotonFanatic]

>would like to keep it under $30.

Jon,

Four pieces to be machined = $7.50 each. Set-up time alone for those four pieces might exceed that dollar figure. You are talking about many operations per piece--cut stock to rough size, face off, turn and bore, cut-off, face off other end.

Not to mention the actual cost of the materials. While small, you still need to have spent some money to have the metals on hand.

Certainly would be a good job for someone wanting something basic to work on, so I'm sure that you'll find a willing machinist, if they have some SS on hand.

Commercially produced parts should be your best bet, when in stock, as those can be produced in large volumes.

 

[jmw19]

I appreciate the reality check - I hadn't thought too hard about the time involved, and I can see how the longer pieces would be tough to work.

I'm still open to offers, since finding the commercial parts in stock has been difficult, and will probably run me $40 with shipping and handling. Maybe that'll teach me to try a shock that uses unconventional hardware.

Thanks,
Jon