OK here we go,I have bought new spokes for my 30x3 1/2 wheels with 1/2 tenon, sanded and finished them. To night I set up the first wheel to press the spokes in and things don't look right. The tenons don't even start in the holes. So I pull one of the spokes out and measure the tenon, it measures 9/16 every spoke I bought measures the same. So my question, is 9/16 right for a press fit or should the tenon measure 1/2 for a press fit?
Thanks in advance
Wrong spokes. Should be 1/2" tenons for 1/2" holes.
How are you measuring the tenon on the spokes?
This is from:
The spokes are from Langs. I talked to Dave at Langs today who had a Ford spoke drawing to consult. The tenon diameter was specified as 17/32 - 35/64 which to 3 places would be .531-.547. Every one of my tenons is in tolerance. Great support from Langs! Info kept me from turning them down and ultimatly spoiling them. Spoke length is more difficult to determine since the drawing did not include the cut out for the hub, but as we discussed, the length question I had is most likley a case of comparing my original 81 year old used spoke against a new never-been-pressed spoke."
Jim, I just held a tape measure up and eye balled them. Today I will check them with a digital caliper at work. They may be within the tolerance of 17/32-35/64, I will post what I find later today. As they sit right now it just looks like a very hard press fit.
The 1/2" tenons are not 1/2". As mentioned above they are oversize as they are a press fit into the hole. Also be aware that the diameter of the tenon can grow or shrink depending in the amount of moisture in the wood. The spoke is made with the wood at a specific moisture content. The dimensions are only valid for those conditions. If you are in a location with high humidity then the tenon can be larger than the specification. Likewise if you live in the desert with no humidity, then the tenon size can be smaller than the spec. I did a test once where I had a spoke which had been sitting in front of the hot air duct from the furnace for a while. I measured it, then threw it in a pail of water overnight. The next morning the diameter of the tenon was something like 1/16" larger.
Trying to make precision measurements of wooden parts can be challenging. It may be in spec today, but if it rains overnight it may not be in spec tomorrow.
So I did some checking with calipers. The tenon on a new Stutzman spoke measured .519" to .522", depending on where I measured it. The holes in a steel felloe ranged from .481" to .498". Obviously, these felloes are stamped parts, not machined for precision, but the "squeeze factor" between holes and tenons appears to be about .030". We're talking half inch holes here. The larger holes in another felloe measured measured .583" to .597". I don't have a large-tenon spoke to measure, but I expect it would probably be around .625".
After checking one of my new spokes with a digital caliper today the tenon measures .5475
Right at the upper tolerance that Jim posted. All looks good at this point so I'll press on. Thanks to all who responded.
The holes in the felloe bands are always rusty and will need a reamer ran thru all holes. If the rusty holes are not reamed some tennons will be loose. The tennon should be .005 -.008 inch bigger than the hole. Use a rubber mallet and drive each spoke into the felloe band before trying to press spokes in.