Guys, I'm about to buy my first forstner bit so I searched the forum for "forstner" and the diameter usually mentioned is 1 1/4'' (which is something over 30mm).
The vulcanite rod stock I ordered earlier is 18mm and in general I haven't seen anything bigger then 24mm. Being complete beginner I wonder whether I really need forstner bit that is ~30mm...
The obvious quality to look for with these tools is the ability make flush surfaces and I would think that the smaller diameter improves the chances of having a "flatter" edge. Is this a correct assumption?
Does the fact that the edge is tungsten or high speed steel means that it's "flatter" then the carbon steel?
The price difference is mainly between carbon and high speed steel but even knowing little about these things I feel that forstner bit is not exactly a tool where saving money helps.
Do not skimp on your Forstner bit - assuming that you're going to follow a procedure similar to mine, a crappy Forstner bit will ruin your day. That said, most good quality Forstner bits are relatively inexpensive. Expect to spend about $15US for a good one. Definitely steer away from sets of 10 for $20US.
Tungsten coated bits are a gimmick, in my opinion. The tungsten is only a molecule or so thick, and will wear off quickly.
The difference in carbon steel and "high speed steel" is in edge wearing properties. Carbon steel is not very descriptive of the actual properties of the steel, and can be anything from 1075 or 1095 steel, to something like 1525. I always shy away from steels that are designated only as "carbon steel". You might get something made from 1075, an inexpensive steel good for large knives and swords due to flexibility and resiliency, but not good for tools. I have a set of kitchen knives made from 1075 that are the bees knees, and can be sharpened to a razor fineness in seconds - but need constant attention to maintain that edge.
High speed steel refers to a huge variety of tool steels that are an alloy made of steel and more than 7% of a combination of tungsten, molybdenum, vanadium or cobalt. They also must contain carbon (duh, which makes it steel). These steel alloys are able to withstand higher temperatures than plain carbon steel, allowing them to cut at faster speeds and for longer periods of time - hence "high speed steel". These are the better choice for hard woods like briar.
Forstner bits can be sharpened to some extent, but efforts to do so may introduce irregularities which may show as grooves or rings in the cut surface.
Steel designation has little to do with how sharp or flat the tool is. That is dependent solely upon the manufacturing process. Steel type can influence edge holding and resliliency however, and ease of sharpening.
Smaller diameter does not automatically mean a flatter edge. Again, this is dependent upon the manufacturing process, and the quality control of the manufacturer.
All of that said, my personal preference is the "precision ground" 1-1/4" forstner bits made by Freud. I get them at the local hardware store. They last a very long time, and when they're dull or get damaged, I just toss them and get a new one.
Thanks Kurt! I'll go go HSS bit. The one on the site I mentioned in the first post will work out to be around $30US. I don't mind paying the money, I was just wondering whether I'm not going to end up with a super sharp high speed steel/tungsten edge that is uneven.
@Karol
If you're using a lathe to turn your stem tenons, you don't necessarily need a Forstner bit to "face" the end.
Regular lathe cutting/turning tools will do the same thing.
Regards,
Frank.
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Frank wrote:@Karol
If you're using a lathe to turn your stem tenons, you don't necessarily need a Forstner bit to "face" the end.
Regular lathe cutting/turning tools will do the same thing.
Frank unfortunately I'm not that lucky and a drill press will have to do. I'm determined to make it work
Karol wrote:Thanks Kurt! I'll go go HSS bit. The one on the site I mentioned in the first post will work out to be around $30US. I don't mind paying the money, I was just wondering whether I'm not going to end up with a super sharp high speed steel/tungsten edge that is uneven.
/Karol
That's anybody's guess, unfortunately. I'm not familiar with that tool brand. However, if it doesn't meet your needs, you could just return it.
I'm determined to make it work 