cutting threads in bolts

learn

Where in Dublin could one get this done ?

mawk

Can you explain a little better please?
Are you looking to repair broken bolts, or make threads in something in to which a bolt will go?

Both are actually do at home easy diy type jobs

You just buy a tap or die and twist on to what you need threaded

pappyodaniel

Well if it's a specific part you need made up your first port of call would be a Toolmaker.

CatFromHue

You could just get threaded rod and cut it and nuts or get some set screws (set screws are fully threaded unlike bolds which are only partly threaded) instead

learn

mawk wrote: »

Can you explain a little better please?
Are you looking to repair broken bolts, or make threads in something in to which a bolt will go?

Both are actually do at home easy diy type jobs

You just buy a tap or die and twist on to what you need threaded

My objective is to cut a thread in a short length of steel rod that would fit into a bicycle crank instead of pedal. Small gym weights to counteract the weight of the other leg would then be slipped on this and secured. This is for use in single legged counterweighted pedalling to improve performance in legs (blood flow etc).

Turbulent Bill

learn wrote: »

My objective is to cut a thread in a short length of steel rod that would fit into a bicycle crank instead of pedal. Small gym weights to counteract the weight of the other leg would then be slipped on this and secured. This is for use in single legged counterweighted pedalling to improve performance in legs (blood flow etc).

The cranks will be tapped (which means they have internal threads), so you can just screw the weight - holder into them.

I'd buy a cheapo pair of plastic platform pedals, then hack them to secure the weights. Bear in mind that the left and right pedals have opposite - handed threads, so you'll need a pair if you want to weight both sides.

mawk

learn wrote: »

My objective is to cut a thread in a short length of steel rod that would fit into a bicycle crank instead of pedal. Small gym weights to counteract the weight of the other leg would then be slipped on this and secured. This is for use in single legged counterweighted pedalling to improve performance in legs (blood flow etc).

Well some threaded rod is probably the easiest solution.

But I'm not sure I'd be au fait with the idea. The weight on one side will cause a fairly rough vibration/oscillation. Depending on the weight and how fast you pedal, this could make the bike very unstable and throw the rider off

learn

mawk wrote: »

Well some threaded rod is probably the easiest solution.

But I'm not sure I'd be au fait with the idea. The weight on one side will cause a fairly rough vibration/oscillation. Depending on the weight and how fast you pedal, this could make the bike very unstable and throw the rider off

Thanks for the advice, these will be used on an indoor trainer setup. The idea came from Jim Martin U.S.A., Hello All:
Counterweighted single leg cycling was my idea. I developed it in my lab and I'm the senior author on the paper which is the result of my sabbatical at Edith Cowan University.
By adding a counterweight to one crank, you can pedal with one leg but with biomechanics that are similar to those during normal double leg cycling. Much different than you would do during non-counterweighted single leg cycling.
The rationale for the study was that you would only exercise half the muscle mass at one time and therefore essentially double the available supply of oxygenated blood. This was well supported by the result that the participants trained at greater per-leg power during single leg than during double leg. While it is true that we did not obtain a performance improvement we did not really expect it after only 6 total workouts over three weeks. Anytime you design a study you are constrained by what you believe the participants are will to do and how much time they will take off of their normal training. We decided on three weeks knowing it might not improve performance. That's where the analysis of muscle biopsies came in. We pulled biopsies before and after each block of training (single and double) and analyzed the tissue. The results for increases in glut-4 (insulin and contraction mediated glucose transporter) and CoxII and CoxIV (limiting steps in the respiratory chain) are highly compelling. They suggest that this will be a potent training stimulus as well as clinical modality.
Cheers,
Jim

K.Flyer

Turbulent Bill's suggestion is probably your best bet, as it will save you a lot of time as well as money. (I'm coming at this from an engineering background)
Firstly there are so many different types of threads, unless you know the specific thread and its size then you are off to a very slow start. Next, buying threaded bar, its usually bought in minimum of 1metre lengths, which is probably well more than you need.
And finding somewhere with any decent range of threaded bar will be tricky.
You could buy a small threading set, but you need to know if the thread you are creating on the blank rod is compatible with the thread on the crank!! again, a lot of money for a one-off job, especially as you will need a left hand and a right hand set.
I imagine a couple of sets of cheap pedals will get the desired result and save you a lot of time and trouble.