[PostMo]

Also, I've thought about a reversible shaper, but they all seem to be built into a table and I'm not sure how I would integrate that into my current table.

 

[CharleyL]

It's possible to make a router run in reverse electrically speaking, but having someone well experienced in brush type motor service will be needed to change the internal wiring between the coils and brushes will be needed. An electric motor rewinding shop is my best suggestion for this. Then there is the problem of keeping the collet tight, since the right hand threads of the collet and shaft are going to loosen from vibration when running backwards, and you don't want a router bit getting loose at this speed. So a special armature and collet, both with left hand threads is going to be needed. If you find a source for these, you had better buy extras, since the tooling costs to make these special one off is going to be very high. Then there is the soft start circuit in the router that will likely need to be made special with different components.

I have no one to suggest for getting this done, except maybe the router manufacturer who sells you the router for the other side of this project. Good luck in getting this. Manufacturers don't like one-off specials. They interfere with normal production.

Charley

 

[Bob Bengal]

There is a way that doesn't involve a reverse rotation router.

Have one router below the table, one mounted above in the hand held orientation. But then the upper router is in the way of using push sticks etc? What are the dimensions of your pieces?

Edit:
Oh I see you said 2x3 inches, what about length?

The normal router table fence, feather boards or rollers holding the work piece against the fence and from above holding it down. An added miter track that keeps a pusher centered? This kind of track:

Amazon.com

So it doesn't lift up. Seems like that could be fast.

How about a photo of the pieces you are making? Or is that proprietary etc?

 

[PostMo]

Sorry Bob, I think I gave the wrong impression. The pieces are 2x3.5 inches in length and only 3/8ths of an inch thick. Overall, these pieces are VERY small. That is why this is so hard and non-standard. I'm currently feeding it with a custom setup using a power feeder. Does 2 pieces per second.

 

[PostMo]

So I've found a reversible round spindle that's 3.1 inches, and a router table lift that accommodates 3.2 inch round routers. So I don't have a solution yet, but I'm getting VERY close.

 

[MEBCWD]

You might want to look into using a spindle instead of a router. They can be easily reversed and are built for continuous use.

 

[PostMo]

You might want to look into using a spindle instead of a router. They can be easily reversed and are built for continuous use.

I'm just trying to find a spindle large enough diameter to put into a router table lift. Alibaba probably has one, but searching for spindle brings up too many things. When I finally find one I'll post it here for posterity.

-Kelly

 

[Alphonse53]

With variable speed and soft start routers these days, has any found one that is reversible so that 1/2 inch shank shaper bits can be inverted and run backwards?

 

[malb]

I doubt that a bidirectional router will ever happen, there are too many issues with the concept.
People having problems with bits climbing in collets are more common than most would like with the collet thread optimised to tighten with normal rotation, when you reverse rotation, the collet would want to release and throw bits.
The armatures are normally advanced relative to the the field windings for better efficiency and more power in the normal direction of rotation, attempting to operate in reverse direction with the same timing in the armature would lower efficiency and output power.
The motors are fan cooled with a fan integral to the armature, the blades being set to exhaust air toward the bit to try and keep dust clear and improve user view of the task, and also to avoid drawing dust into the high speed, minimal air gap motor. Being able to reverse the motor would suck dust into the motor and clog it fairly quickly.
Users often find themselves confused about appropriate feed direction differences between working on external surfaces vs internal surfaces, being able to operate the motor in reverse would add greatly to this confusion by adding another pair of potential scenarios to consider.
Finally, what diameter bits would you want to be running, could the variable speed systems slow the motor enough to retain a safe tip speed while maintaining torque to do the job, overall efficiency and adequate cooling? Do you really want someone trying to run a router with a heavy bit hand held?
Manufacturers potentially could make a dedicated reverse rotation model with timing, collet threads, fans etc optimised for the reversed rotation, but that would be a very limited market in comparison to the regular models sold worldwide, and potentially a further source of confusion for those not knowledgeable about routers.

 

[MikeMa]

As malb said, it is unlikely bi-directional routers will happen. If there is a need for this, looking into shapers will be your best bet.

 

[DesertRatTom]

Reversing the direction would probably end up loosening the collet. It doesn't take much to do that because the difference between a loose and a tight collet is in thousandths of an inch. And the majority of bits are milled to cut in one direction only. They would easily bind., jump out of the collet and do major damage as it careened from on object to another in the shop, including you.

 

[sreilly]

I can't imaging a good reason much less safe one for this to be done.

 

[Alphonse53]

I doubt that a bidirectional router will ever happen, there are too many issues with the concept.
People having problems with bits climbing in collets are more common than most would like with the collet thread optimised to tighten with normal rotation, when you reverse rotation, the collet would want to release and throw bits.
The armatures are normally advanced relative to the the field windings for better efficiency and more power in the normal direction of rotation, attempting to operate in reverse direction with the same timing in the armature would lower efficiency and output power.
The motors are fan cooled with a fan integral to the armature, the blades being set to exhaust air toward the bit to try and keep dust clear and improve user view of the task, and also to avoid drawing dust into the high speed, minimal air gap motor. Being able to reverse the motor would suck dust into the motor and clog it fairly quickly.
Users often find themselves confused about appropriate feed direction differences between working on external surfaces vs internal surfaces, being able to operate the motor in reverse would add greatly to this confusion by adding another pair of potential scenarios to consider.
Finally, what diameter bits would you want to be running, could the variable speed systems slow the motor enough to retain a safe tip speed while maintaining torque to do the job, overall efficiency and adequate cooling? Do you really want someone trying to run a router with a heavy bit hand held?
Manufacturers potentially could make a dedicated reverse rotation model with timing, collet threads, fans etc optimised for the reversed rotation, but that would be a very limited market in comparison to the regular models sold worldwide, and potentially a further source of confusion for those not knowledgeable about routers.

Thanks for exposing all the obstacles in the way of the concept! You must have thought or read about this yourself!

I can't imaging a good reason much less safe one for this to be done.

There are two types of tool users: Those who use what's available and imagine something better and those who accept them as they are....

 

[Biagio]

The question jogged some memory cells that are still working. See Reverse Rotation Router… from earlier this year.

 

[Alphonse53]

My job involves rounding over many thousands of small (2x3 inches) wooden parts. I have a VERY custom setup that's pushing small pieces through a table mounted router very quickly. Currently, I'm processing about 2 pieces per second. It's taken me about 6 years to get to this point. In order to process both sides of my piece, I currently have to put them through the machine twice. This turns out to be quite expensive in terms of labor, so I'm ready to spend the money necessary to fix this problem for real. The simplest way to optimize would involve a second router on the other side of the track spinning in a reverse direction. I've found a supplier for reverse bits. I understand that there are spindles that allow for reverse rotation, but I don't know how to mount them under the table in a way that I can easily adjust the height of the blade. I really like the SawStop router table lift that I got but I don't think it will mount a spindle, though the Jessum looks nice too. I've heard that you can mess with the wires inside a router to reverse the rotation, and this sounds doable, but there may be issues with the bit mount loosening up over time and I'm not sure if it would affect the life time of the router. Ideally, I think, a spindle mounted under the table sounds like the right approach, but I'm open to other suggestions. However, I don't know of a spindle mount that goes under a table in the same way a router table mount does. Any suggestions would be most welcome. If you want to propose a custom build, money shouldn't be a huge issue on this one. If anyone knows of a round spindle, that would also be super helpful. I'm not sure why they are all mostly square. No idea is too out there on this one.

I inquired recently about a reversible router and got called everything but foolish. Out of several discussions, the most critical design change would be in the collet. Either a left hand threaded nut and spindle or a bolt drawn collet through a hollow spindle would be the best options. Do a search of 'Reversible Router" for the particulars.

 

[Alphonse53]

Have you had any luck finding bits that cut the opposite direction?

I recently machined a piece of 4140 (gun barrel steel) to adapt the old style interchangeable Craftsman carbide bits to run at an extended height since I couldn't find a way to run them backwards, although it is possible to run then in reverse if the lock nut is threaded left hand when you make the spindle.

 

[Alphonse53]

The question jogged some memory cells that are still working. See Reverse Rotation Router… from earlier this year.

THANKS! This is the most intelligent response I've received. Search words do matter, but a good memory works better!

 

[DesertRatTom]

Hope you have a good machinist in your area. Without changing the threads, which means building a custom armature and shaft, I don't see how you can safely use such a setup. How big is this roundover? 1/8th or so? I can picture an automated jig that reverses the piece and sends it off into a second bit rotating normally, but I would not want to hand feed such a beast. The piece could simply make a right turn with a mechanical push lever, then routed "downward" into a second router turning in the normal direction. It would require devices to keep it aligned and pushed down.

I'm thinking it will take some time to engineer and manufacture such a device, so it will take a lot of time to amortize the expense if you're just talking about operator time to push the piece through a second time. I used to work with a guy who did production line engineering, so I know it can be done by rotating the piece and automating sending it through the second, regular, unmodified router. That's what I'd be considering. Perhaps a photoelectric switch that activates the kicker when the piece clears the first bit. Then rollers and a constrained pathway to move it through the second bit with sufficient down pressure.

If your company worked 3 shifts, the amortization would go faster, but you're only talking a few seconds of operator time per piece. Perhaps you just need an automatic stacker to pile up the pieces after the first pass in an orientation that makes it easy and quick to send them through for the second pass. That might cut a few more seconds off the time to do the individual pieces.

No put down intended here. Really trying to think this through. With a computer controlled device, you are talking at least $50,000 and up for the device, and that's optimistic. But at least you could use conventional routers and bits and reduce the risk of a bit coming loose and bouncing off you and all the other things in the area.

 

[mgmine]

Why not route long boards and then cut them to length? It seems it would be a lot quicker and safer than trying to do the edges on tiny pieces of wood.

 

[difalkner]

We certainly have enough 'reverse rotation router' threads but here's a commercial operation at Taylor Guitars where they have a reverse rotation router for their headstock trimming -