Hole Cutters & the PP

keakap · Post by **keakap** » Mon Apr 22, 2013 9:21 pm

Just was reading a mag article on those circle or hole or wheel cutters- you know, those things that look like no one should be in the same room when they are operating?

Center shaft holding a 1/4 drill bit or pointed rod, cross bar either bar or rod, with one or more blocks either holding or part of a arm ground to a cutting edge on one or both ends. Never have I ever agreed more hole-heartedly with the injunction to "Use on drill press ONLY". I can't look at one without thinking "man if that, or THAT, ever came loose when it was running..."

But anaway, one thing of interest in the story was the difference between a hole or circle cutter versus a wheel cutter. I've got one of these things and never noticed. But it makes sense- if the cutting edge, which looks sorta like the angled band saw blade guide used to twist the blade for long piece crosscuts, is breaking thru the cut on the outside of the circle you'll have a clean circle, but if you're cutting a wheel you'll have a rough cut. So some devices have two edges so you can put the business end on the inner circle of the groove cut, giving you a clean edge there, on the inside of the groove or the tread of a "wheel". Mine is one of the one-sided types, and it is adjustable and removable, so I could reverse it, putting the cutting edge inside, but the whole thang would have to be driven in reverse. Since this thing can't be used in a hand drill (by a sane person) that reversability is wasted.

BUT! (drum roll please)
The Power Pro can run in reverse!

So of course I have to try this blasted thing out.

If anyone reads this and can think of a decent reason why this should not be attempted I hope you'll stop me in time.
The unit I have is a General tool, and has worked before in its standard setup. Seems to be stout and sturdy enough, but I have this uneasy feeling I may be missing some really basic engineering no-no for running stuff backwards. But then for all I know there hasn't been a reverse running drill press before the Shopsmith came up with it.

?

JPG · Post by **JPG** » Mon Apr 22, 2013 10:23 pm

Makes sense to me(maybe that is a warning:D).

I have used those gizmos with a hand drill, but, proper orientation is critical(that is an understatement;)). Two hands recommended!:rolleyes:

I prefer an adjustable hole saw(from a half century ago). Wheel removal can be a 'pita'.

Always Always Always clamp the workpiece securely.

Did I mention to clamp the workpiece?

Oh and properly secure the workpiece.

billmayo · Post by **billmayo** » Mon Apr 22, 2013 10:33 pm

Most of the type of hole cutters you discribed are for slower rotation speeds. I would be afraid that with the Shopsmith Mark V slowest speed (750-800) RPM, any slight jamming or hanging could be very dangerious or could bend the quill shaft. I have been converting a few of the Shopsmith motors for reverse rotation for many years. This does require some knowledge of electric motors and good soldering techniques.

reible · Post by **reible** » Mon Apr 22, 2013 10:47 pm

Just so we make sure we are all on the same page. We are talking about a "circle cutter" right?

If you go to this post you will see a picture of one of mine.

https://forum.shopsmith.com/viewtopic.php?p=34246&postcount=42

The following post shows an example of the hole it cuts.

https://forum.shopsmith.com/viewtopic.php?p=34249&postcount=43

If yours looks like the one pictured it turns and CUTS in only one direction. If you were to reverse it the chain of evens would lead to burned wood and a ruined cutter.

There are several styles of these, it is possible that some could run backwards.... I can't say I've ever seen one that did.

I use to use this type bit ages ago in one of those drill presses that held a hand drill.... made holes for birdhouses.

Ed

reible · Post by **reible** » Mon Apr 22, 2013 11:08 pm

Yea I guess I should have added that the max rpm is 500 on mine. That works with the speed reducer or with the powerpro, not so good for other 700 rpm lower limit machines.

The one pictured will go up to almost 8", I've personally never went that large and I think I'd be going at an even lower rpm if I did that.

Ed

keakap · Post by **keakap** » Thu Apr 25, 2013 12:55 pm

JPG40504 wrote:...Always Always Always clamp the workpiece securely.
Did I mention to clamp the workpiece?
Oh and properly secure the workpiece.

Sounds like holding the workpiece down on the table with Scotch Tape may not be sufficient...

;-)

keakap · Post by **keakap** » Thu Apr 25, 2013 1:03 pm

billmayo wrote:Most of the type of hole cutters you discribed are for slower rotation speeds. I would be afraid that with the Shopsmith Mark V slowest speed (750-800) RPM, any slight jamming or hanging could be ...

Good point, Bill. Last time I used one, in drill press mode, I was very conscious of the speed factor, and did what JPG suggested- clamped everything down every which way, to the max, and proceeded with great caution and very slowly. Also working with redwood, which is very soft and eminently destructible.
Now with the PP the speed can be down to 200rpm, and down even more drastically with the speed reducer. {but can the speed reducer run in reverse?}

Hm, I can almost convince myself doing this in reverse might be okay after all...

JPG · Post by **JPG** » Thu Apr 25, 2013 1:04 pm

[quote="keakap"]Sounds like holding the workpiece down on the table with Scotch Tape may not be sufficient...

]

Not even grinding tape!:rolleyes:(super sticky double sided machine shop stuff).

JPG · Post by **JPG** » Thu Apr 25, 2013 1:07 pm

I do not know re the speed reducer, but, since it is belt drive, the answer is likely yes.

I await yer own opinion after attempts.

keakap · Post by **keakap** » Thu Apr 25, 2013 1:14 pm

reible wrote:Just so we make sure we are all on the same page. We are talking about a "circle cutter" right?

If you go to this post you will see a picture of one of mine.

https://forum.shopsmith.com/viewtopic.php?p=34246&postcount=42
...Ed

Yep, that's the one the article said had a cutting edge on each end, so you could pop it out of its housing, turn it over, and make it cut inside or outside depending on which end. Termed circle cutter on one end, wheel cutter using other end. Still ran in one direction only.
Mine's only got one cutting edge, but it can be turned around and IF run in reverse would change to "wheel", etc.
Of course neither the article or the maker wants to talk about running in reverse. Cant blame 'em.
Thanks. Good picture, and I've never seen one that clearly befo.