The following is a continuation from our last blog on ROUND bar clean up.
It is important to share both your finish diameter AND length. They would like to know if you have a short stubby shaft, where straightness is not often an issue. Or, if it is a small diameter shaft that is 18ft. long. Big difference in how you approach the raw material for the job.
We are not suggesting that you ask the supplier what size they recommend, since a savvy supplier will avoid answering that. Yes, they are there to help you, but they can’t possibly know how talented you are in making a difficult shaft. It always comes down to; When things go South, who’s wallet comes out? Sufficient stock allowance for one, might be trouble for another.
You might also share information on what grinding, or machining method you intend to use; are you grinding or turning on centers, or will it be a centerless operation; which is by far the most common. Clean-up stock and straightness requirements will be different.
What surface finished are they able to supply? Do they have pre-machined, or, rough turned stock, is it fine-turned, cold drawn, hot rolled, or as-forged? Each may have a different allowance for removal that has been left on the bar. There are of course standards that govern each type of finish, BUT, there are variances from one mill to another.
Share “end-use” information with the supplier. What is the application it is being used in. If you are making Hydraulic Rods for instance, that would be an important bit of information you might want to share.
Subsequent Operations that will be incorporated, is also important. Will you be changing the hardness, adding surface hardness or surface-coating? If they don’t seem to be interested, no harm done. They just assume you’re verbose. A good supplier, however, will recognize that your contributions are important to a successful transaction.
In the next post, we will finish up elaborating on the last of the 10 points relative to “Stock Allowance on Round Steel Bar”.
-Howard Thomas, March 6th 2019