I have just got a metal lathe and was wondering what type of steel I should use for reamers. Ive used flat reamers until now made in gauge plate but feel that I cant get them as accurate as Id like. Im in the uk.
Cheers
Bob
“electromail” in the UK (radionics in the ROI) sells “silver steel” which is the right stuff. It’s sold in packs of 1 metre length. I’d suggest a pack of 6mm and a pack of 10mm for starters. You can get shorter sections, suitable for “foot reamers”, in larger diameter from axminster.co.uk. Using the three sizes will not only give you flexibility in their use, and make them easier to use, but easier to make, as you won’t have to remove so much steel at the throat end.
Don’t bother trying to heat treat the steel - it’s liable to warp and not trivial to heat-treat in a home workshop. It’s plenty hard “as sold” and D reamers are trivial to sharpen - so easy to keep them sharp, the edge life is not such a big deal.
“Silver steel” is not sold as such in the US; I’ve heard reports of people using both O-1 and A-1 drill rod, more readily available in the US, with good results.
O1 tool steel has always worked quite well for me. It’s easy to get, dirt cheap. Comes in a wide vartiety of sizes and thicknesses. It comes in a hard annealed state. So you CAN work it. Don’t let it overheat (where the edges turn blue). Even working it with a file can create a great deal of heat.
I have a number of “fancy” reamers made in assorted and sundry styles, but frankly I find I can get exactly the results I want from flat stock O1 reamers.
Like Bill says, I don’t generally bother with heat treating it unless I am VERY sure the reamer dimensions are exactly what I need and are precise. Once it’s hardened, you won’t be making any major dimension changes..just sharpening the edge to get a nice “scraper” burr. Keep in mind these are not exactly “reamers” in the sense that they don’t do any actually cutting. To be precise, they are scrapers.
I actually prefer to keep my flat reamers un-heat treated as I tend to continually sharpen them and will make changes to the reamer dimensions on-the-fly for tuning purposes. Once you get the hang of making and using a flat reamer, they are a piece of cake.
ATB,
David B.
www.greenwoodpipes.com
Just to clarify about my own current practices, I prefer D section reamers to flat ones. Among other things they are less likely to chatter; however David’s post underscores the point that makers’ preferences differ.
I also don’t leave a burr on my reamers - my feeling is that the burr introduces another level of uncertainty into the bore profile, since it can cause the reamer to cut a little bigger than its “nominal” size (I had this happen with a fluted reamer, and it did affect the resulting instrument; and I thank DMQuinn for alerting me to this possibility.). Of course this could be compensated for or at least detected with careful aprés-reamer bore measurement, which is probably a good idea anyway.
In a woodturning “scraper”, it’s the burr that does the cutting (therefore at a microscopically-positive rake), or so it’s often said. I prefer to think of the reamer as a zero-rake cutter; ebony and other really hard woods seem to cut fine with zero or even negative rake. If you were using these reamers in softer wood for some reason, it’s logical to think that a slight burr might be advantageous for cutting (though you’d still have to allow for dimensional effects from the burr). In my experience the softer timbers (by softer I mean pear, apple, and the like) present other challenges as well, so what works for one may not work exactly the same way for the other.
best regards,
Bill