Converting a radial arm saw into a (radial) overhead pin router

[Quesne Ouaques]

Hello Fellow Creekers:

I just thought I would share a recent shop project I've been working on.

A few weeks ago, I came across a radial arm saw with a broken motor pivot mount but in otherwise decent shape. I've always wanted an overhead pin router for template work, so I thought it would be a fun project to mount a router on the radial arm carriage. $10 and a short drive home brought it into my shop.

I just finished the final setup today, and I am posting the videos I've made so far. I will be making one or two final videos to show it in action, but I've already made a few cuts and it seems to work pretty well.

Comments and suggestions are welcome....thanks in advance :-)

1. Explaining the project for my Dad's benefit, and showing him the two routers (http://youtu.be/LosiGT87s0o) (optional)
2. Stage 1 (http://youtu.be/JNWUn8Mop0g)
3. Stage 2 (http://youtu.be/cK6IROJ3zX0)
4. Resizing the router support box (http://youtu.be/d43ioX4GvcM) (optional)

[Jeff Duncan]

I would suggest being very careful and taking very light passes with that setup. The Craftsman RAS's are not overly robust machines and having a bit of flex in the arm is not great for pin routing. If you look at pin routers the arm is usually quite a massive piece of iron to minimize the potential for flexing, which when running bits in the 20k rpm range would be bad. Not saying it can't be done successfully as I haven't tried it, (and honestly I wouldn't). Just saying to be very careful:o

good luck,
Jeffd

[Myk Rian]

I kept skipping ahead in the videos to see if you actually mounted it.
Awful long to wind up without the finale.

[Quesne Ouaques]

Hi Myk:

Yes, I know. My apologies.

I tried to add the final video after I published the thread, but could not. This is the final video (http://youtu.be/tzQ1mza1G-8) with the router mounted and ready to cut.

I will post another video with some sample cuts and measurements.

Thx

[Myk Rian]

You could shorten it by showing the box, how you mounted it, and an actual test. Cut it down to 5 minutes as opposed to 45.

[Rick Potter]

Looks like it might work ok. Anxious to see it work. Your second box is much better than the first idea, and it looks sturdy enough. Some of the ideas on YouTube are scary.

You will want to adjust the play in the rollers a bit to get rid of that slop. So far it is an overarm router, but not a pin router. Do you plan to put a pin setup in it for pattern routing? You could do some edge work (fence) and pattern routing with it now, but only with bits that have a bearing above the cutter.

Rick Potter

PS: Quesne Ouaques, or Ken Wachs?

[Rick Lizek]

In my experience using pin routers, the radial armsaw falls far short of a pin router. Being able to raise and lower the cutter for internal routing is what makes a pin router so unique

[johnny means]

Dadoes? Yes. Surface planing? Probably. Pin routing? Doubtful. It's missing the two main features of a pin router, an inflexible arm and an automated plunge mechanism. What operation do you see this thing doing? The yoke and arm assemblies on those saws is barely up to cutting straight lines. Internal routing, plunging, or pattern routing is likely to be real sloppy. Probably would be better just to weld the entire thing solid. Good luck.

And remember this: there is no more important safety rule than to wear these — safety glasses.;)

[Quesne Ouaques]

I would love to be I don't know how to cut and paste the videos.

[Tom Giacomo]

I think you can get it to work. I did a very similar thing with a much older Craftsman RAS.

[Quesne Ouaques]

Yes, I agree about the final box format. It feels very strong, and in making some fairly aggressive test cuts, 1/2" x 3/8" (posting video in a few minutes) , I've gotten much less deflection than I had originally anticipated.

I do intend to create a pin setup, though I am a little confused as to why I cannot use top-bearing bits. Can't my template simply be on the bottom of my workpiece?

P.S. Quesne Ouaques is the spelling of my name in Algerian French. Strange but true :-) I sometimes use it as my login name

[John Bomment]

Reminds me a bit of an old Montgomery Ward Power Craft Radial arm saw I used to have.
They had a "power panel" that could be flipped down (or around) with two spindles on it.
One was 20,000 rpm for router bits and the other was 3450 rpm for sanding,polishing,drilling.


http://vintagemachinery.org/photoindex/images/8282-B.jpg

[Quesne Ouaques]

Here is a video of two test cuts I made (https://www.youtube.com/watch?v=h-yWTBOw9_o&feature=youtu.be). BTW - I installed the movie editor that came with my wife's camera, so I was able to make the video shorter (riotous applause ;-)

The 1/2" x 1/4" dado is pretty much perfect on depth, width and square. The 1/2" x 3/8" rabbet is excellent on flatness and square with some edge deflection toward the end of the cut.

The roller bearings could probably be tighter, but I also think I would have gotten better results with 2 or 3 lighter passes.

Overall, the tool feels pretty stable and I'm generally happy with the cut performance. I see this setup as a prototype until I really figure out what it's good for.

[Quesne Ouaques]

Thanks very much for the concern, Jeff. You and I are of one mind on that matter.

In the videos, you can hear that I am very concerned about the safety issues, and I am planning to do quite a bit of testing to establish the "behavior" characteristics under different types of cutting conditions.

I do expect that it will be stable, though I'm not sure what level of precision I can expect :-)

[johnny means]

I see a very quick and easy to use french dovetailer. Also, stopped dadoes couldn't be any easier.

[Rick Potter]

Ken,

Top mounted bearings are the type that will work on your setup. Top mounted means the bearing is on the shaft side of the bit. A bit confusing, since router bits in a router table are upside down. You might want to try a spiral upcut bit also, they cut pretty nicely.

Looks like it works pretty good.

Rick Potter

[Quesne Ouaques]

To those who are interested, here are two more videos of projects with my radial arm router. I sped them up so you don't need to spend a lot of time watching. The sound was too bizarre in the second one, so I just cut it out :-)

1. Jointing / planing coaster blanks cut from thick branch cross-sections:

http://youtu.be/O7x939mEKTE

2. Jointing / planing hickory panels to augment my table saw fence:

http://youtu.be/kG6hbod69xY

[Alan Schwabacher]

Here are some thoughts on the sideways deflection you get in the test cuts video.

The spinning bit cuts in front, and the cutting edge is moving sideways (right) as it cuts. This puts a sideways (left) force on the bit to deflect it in a way that a sawblade does not. The harder you push, the more sideways force you'll see. That means for an accurate straight edge to a rabbet or dado, you might want to hog out the waste first at a slightly smaller dimension, then make a final skim pass to cleanup/straighten the edge of the cut.

If you pulled instead of pushed, the bit would deflect in the opposite direction. If the bearings are very sloppy, your best bet for a straight cut might be to keep to a steady advance with a substantial cut, as this will hold the router tight to one side.

Of course, taking as much slop out of the carriage bearings as you can is top priority.

[Mark Bolton]

I had a friend that used a massive RAS to edge production flooring. Ran very large cutters and a feeder but the same principal.

If you switched to larger diameter bits for tenon making or rabbeting your performance would be much better.

I agree the flexure in the craftsman will be what hurts you but all in all I could see it being handy if you have the room. Heck, for what you've got into it why not?

[Rick Lizek]

Without the up-and-down plunge feature you only have an overhead router table not a pin router.

[Ole Anderson]

Reminds me a bit of an old Montgomery Ward Power Craft Radial arm saw I used to have.
They had a "power panel" that could be flipped down (or around) with two spindles on it.
One was 20,000 rpm for router bits and the other was 3450 rpm for sanding,polishing,drilling.


http://vintagemachinery.org/photoindex/images/8282-B.jpg
I had one of those for probably 25 years, it saw lots of use. But generally before I knew of carbide router bits, so my steel ones were always burned out. Very noisy saw with the high speed universal motor and the gearing to the low speed saw blade shaft.

[Quesne Ouaques]

The "pin routing" functionality I was trying to replicate was more along the lines of the MLCS Pin Router (http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/daisypin.html) rather than one of the massive pneumatically controlled plunging machines. I have a 3/4" pin that I will be anchoring into the table (an old carbide router bit shaft). When I get around to doing that, we'll see if it all meets expectations.

In the mean time, I do have a very precise depth control mechanism which I have been using for the planing operations (1/4 turn = 1/64"). Like any other RAS, of course, it is manually controlled.

[Quesne Ouaques]

So far I've tried a few different cutters for planing, including a 2" diameter glue joint bit and a 1" diameter dish cutter.

The glue joint bit vibrated to much, but the dish cutter did a respectable job. So far, I've stuck with the 3/4" spiral upcut mainly for safety and quality. It leaves a glass-smooth finish and (so far) there has been no kickback or runaway at all, regardless the orientation of the work piece, even if I am in a climb-cut.

It would be great to find a 1" (or greater) diameter spiral upcut bit with a 3/4" shaft. So far, I've not seen one.

[Rick Potter]

Perhaps you could build a simple overlay table with t-tracks or slots in it to give you a sliding table surface? Might be handy.

Rick P

[Quesne Ouaques]

Funny, I had not thought of it that way Rick, but that's just the sort of thing I was thinking about (i.e. a travelling/sliding vice system to hold work and move it incrementally). I am sure that could work great.

BTW - I did find this 2" spiral upcut end mill (http://www.mscdirect.com/product/details/63325237) on the MSC Direct website. It would certainly make planing and hogging operations much faster, as long as the lateral forces don't flex the roller bearings too much.