Tapered reamer

[Mike Henderson]

I need some help and advice from those of you who have made a tapered reamer. Following the pointers you gave me earlier, I made the reamer in the pictures - it's an 11* included angle.

My question is "How much should the blade be exposed on each side?" As you can see in the picture, I have quite a bit of blade sticking out right now. To reduce it, all I have to do is make the blade shorted and less will stick out on the side. But before I do that, I'd like you to tell me how much you have the blade protruding on yours.

Thanks, Mike

[Johnny Kleso]

I would have it out just stick out a hair and add a chip groove on the cutting side of the dowel..

The less it sticks out the more the dowel can help guide the blade..

But I am just guessing I never made one like yours

[Robert Rozaieski]

Looking good Mike! I think mine sits proud of the stock by about 1/8" on either side. It doesn't matter much as the stock never touches the hole. It just supports the scraping blade. If the blade flexes in use, make it narrower (shorter). I'd try a few test holes to see how it works before shortening it. If you take off too much, you can always add a shim above the blade to push it down some. You will likely need to do this in the future anyway after repeated honing of the scraping edge makes it narrower. I can't tell from your picture if you have cut a relief or not but having a relief cut on the leading edge of each side helps with chip clearance and also allows you to make the blade a little narrower. John Alexander's site has a picture of the relief cut.



Bob

[Bob Easton]

Dang! I could have used one of those last week (removing dead knots from a boat bottom). Having nicely tapered holes would have facilitated neater plugs.

Is it really as simple as what I see? ... a turning with a slot and a saw blade? Looks like a keyhole saw. What else should I know about it? THANKS for the pics and inspiration Mike! Headed for the shop...

[Robert Rozaieski]

Dang! I could have used one of those last week (removing dead knots from a boat bottom). Having nicely tapered holes would have facilitated neater plugs.

Is it really as simple as what I see? ... a turning with a slot and a saw blade? Looks like a keyhole saw. What else should I know about it? THANKS for the pics and inspiration Mike! Headed for the shop...

All discussed here http://www.greenwoodworking.com/reamer.htm

Bob

[Mike Henderson]

Thanks for the pointers. I did put a chip relief groove in it. I didn't have one originally, and when I was testing it, the chips (sawdust) was being forced down alongside the blade, which was then pushing the wood apart. Once I put the chip groove in, the problem went away.

It turned out that the blade I used - an old Stanley keyhole saw that I've had for 20 - 30 years - was exactly 11* included angle.

I put together a spreadsheet to compute the width (or thickness) at various points along the taper. So just like you do with any spindle turning, I laid in the proper thickness at those points with my parting tool and a Starrett caliper, then took off the wood between. But as Robert pointed out, the thing that needs to be accurate is the metal - if the wood is off a bit it doesn't matter much.

I specifically wanted 11* but if you're making your own legs, the angle probably isn't critical - you'd just match the taper on your legs to your reamer.

One other thing, since as Robert pointed out the wood is just holding the blade, I wrapped some wire around the bottom of the taper to hold everything together (look carefully at the first picture). Since the taper is used on through holes, and holes are bigger than the tip, the wire doesn't interfere with anything and it keeps the wood from separating when the taper is in use.

While I sharpened the blade already, I'm going to go back and do a better job of sharpening it. It worked well on mahogany but I'd like to improve the cut.

Thanks again for your advice and help during this project. I would not have even thought of making my own without your pointers.

Mike

[Oh, if anyone wants a copy of my spreadsheet, let me know and I'll try to post it here.]

[Second PS - one thing I really liked about this project is that the cost was zero (I'm a cheap person). I used that old keyhole saw that was just gathering dust, and scrap wood. It took time to do, but I learned a new technique and gained an appreciation for how our ancestors did their woodworking. They certainly didn't have an Emhoff machined reamer to make their chairs.]

[Robert Rozaieski]

I'll add to Mike's comments to say that you don't need a lathe to make one either, because the wood only serves to hold the blade. I don't have a lathe and made one by making a square tapered blank (like one would do for making a 4 sided tapered table leg) and then using a spokeshave to make the square taper round. A fun, quiet hour or so to make a very useful tool.