Shopsmith Forums

The chuck arbor seems to be the answer. I will get one on order from SS.

Rob, Thanks for the offer to loan me one, but this seems like a "must have" accessory that will serve me well in the future. Let's see how long it takes SS to ship.

BTW, JPG I have had the pleasure of visiting Rob and really enjoyed touring his SS collection. Truly unbelievable. I think MickyD (also from San Diego) once referred to Rob's shop as Shopsmith West. Right on.

tom k/mo
Now that is an interesting recommendation using a 4 jaw chuck in the tailstock and a drill bit in the jacobs jaw using the quill. I have a barracuda chuck but how would you attach it to the tail stock?

Here is a hairbrain idea that I had....would this work?
Get a 5/8" steel rod and file lip or taper to it and slip it into the tail stock and tighten the jacobs chuck to it and move the quill with the turned piece into the bit mounted into the jacobs chuck.

Bob
San Diego

rdewinter wrote:The chuck arbor seems to be the answer. I will get one on order from SS.

. . .

Here is a hairbrain idea that I had....would this work?
Get a 5/8" steel rod and file lip or taper to it and slip it into the tail stock and tighten the jacobs chuck to it and move the quill with the turned piece into the bit mounted into the jacobs chuck.

Bob
San Diego

Getting the taper correct and inline would be quite difficult. Go with the top choice. If ss cannot ship quickly, consider a visit to Rob!

With a 'tail stock adapter', the barracuda chuck mounts to the adapter the same as to the main shaft. The adapter provides a 5/8" flatted shaft. With the workpiece in the barracuda chuck mounted in the tailstock, it would be stationary while boring the hole.

Let's discuss this "boring end grain with a spade bit issue" a little more - - There are two sub issues that I believe affect the wobble of either bit. These are; bit sharpened cutting angle and heat.

I'm ignoring any shaft issues as these should be constant between the two bits.

To re-iterate what Nick pointed out - a Forstner bit has a cutting edge of 45 degrees. This will work wonderfully for edge or face grain. Like plaining end grain, a lower angle is a lot better. That's why low angle planes are preferred for plaining end grain.

It follows that a lower angle cutter will scrape off end grain a lot better than a higher angle cutter will work to slice off the end grain.

It would be very difficult to re-sharpen a Forstner to 10 or 15 degrees, while that is a fairly simple and normal thing to do to a spade bit.

IMO, The longer sides of a spade bit (flutes) give an advantage to the spade over a Forstner to make a straight hole. Approximately double the side length will serve to cut down any drifting of the bit. The observation that a spade bit only touches the sides in two narrow points at any specific time, gives reason to understand the lessor heating of that bit. These two flute edges, constantly rotating at 700 RPM will produce 1400 contacts of the sides of the hole each minute.

Yes, the Forstner sides (rims) are always in contact with the sides. This constant contact also produces more heat that will tend to widen the metal along with the sides of the hole. This happens by the heat driving moisture from the wood into the hole and softening the wood fibers of the holes edge. This is a major reason why slow boring with a Forstner and repeated removal/cooling of the bit will result in straighter holes.

With a slow feed rate, the rotating side contacts and the scraping action of the spade bit, there is no reason to believe there will be more wobble with this bit.

I spent so much time on e bay looking for a tail stock arbor that wasnt already over-priced, I finally settled for a complete chuck with a #2MT on it and am quite happy, especially as it was about 3 bucks cheaper than tail stock arbors were going for at that time. Just another suggestion.