Overarm Pin Router: why the table?

[rdonr]

Ok, Nick's sawdust sessions have convinced me to add the Overarm Pin Router to my already way too long Christmas list. SWMBO says I've got to actually build something Real Soon Now instead of just buying more tools.

But I've got a question. Why does the OPR need its own table? Understand, I've never actually seen one in person, so maybe it's obvious. Why not just use the Mark V main table? It seems big enough, adjustable both horizontally & vertically, already has a nice fence. Need a split fence? How about Shopsmith's own shaper/router fence? Sacrificial fence or other shop built jigs? Again, wouldn't these be as easy to make and attach to the main table and/or fence as to the added router table? Need an insert for dropping the bit below the surface, or for pin routing? Why wouldn't a shop made (or Shopsmith made) table saw insert work?

Not really complaining, just curious. Without ever having actually tried it, looks like the OPR could be sold without the table and/or with parts intended to be used with the Shopsmith main table.

Hope someone with actual experience can enlighten me.

don

[charlese]

Hi Don- Here's the short answer - with emphasis on the "PIN" in Overhead PIN router:

In order to do pin routing we have to have a vertical pin that is located directly under the router bit. In order to get that pin in place, SS has designed a table having an insert that contains a threaded socket to hold pins of different diameters. They have also included the pins.

Here's the long but more precise answer: http://www.shopsmith.com/ownersite/prod ... Router.pdf
Just download the manual and read it. I was sold on the OPR after reading Nick's description in the Forum, and reading the manual. Got one, and am happy with it. My sweet wife OKed the purchase, as a gift. Yes, it is a big expenditure, but if you do routing work - the OPR can't be beat for it's versatility. The system was hard for me to figure out, as there are many adjustments. The sawdust sessions have helped me to more fully understand it, and it's capabilities.

Remember to get telescoping legs, if you already don't have them.

[rdonr]

Charlese, thanks for the reply.

I've looked at the OPR manual. I think I understand the concept of pin routing. Still don't see why the pin couldn't be mounted in a "pin routing insert" for the main worktable. Similar to a dado insert or a drum sanding insert, etc.

Is there an issue of spacing? Looks like the OPR has plenty of adjustment to allow it to be positioned over the insert area on the main table.

don

[charlese]

Don - When you look at the insert slot in the main table - it is a linear shape with a rounded front. We would have to make a zero type insert with a threaded hole in the right place. This would be a tough job for me, and to get it firm enough and at the same time level with the table top would be a chore for which I would rather buy a table.

Maybe you also noticed the OPR comes with two inserts. One has a hole in the center to allow vertical bits to penetrate past the workpiece, as well as a threaded hole to allow for a starter pin - the other is solid and has a brass threaded hole in the center. The OPR table also comes with threaded inserts and hardware to set up the fence that comes with the unit.

The table that comes with the OPR is a good deal - believe! It is solid, level and has a nice surface that can be waxed, for easy routing. The inserts fit snugly and also are firm.

Plus the new consideration (I learned on the Sawdust sessions) A sliding table with a slot can easily be made to fit the OPR table. This allows horizontal routing with the bit beneath the sliding table. Yes, you could build a sliding table to slide on the main table, but it the slot would always have to be off the main table to the inside. This would put the main table in an extended position and would lose stability.

With the slots, in the OPR table and sliding table, as shown by Nick in the Sawdust sessions, other types of fences can be used in a number of configurations. In other words, the OPR table is easily modified to use in many set-ups. This would be almost impossible when trying to use the main table. Not to mention damage that may occur to the main table.

[Nick]

I had exactly the same reaction, Don, when I first saw the redesign for the Overarm Router, when Shopsmith first took it from a stand-alone tool to one that works with the Shopsmith system. It seemed to me all they needed was a clever table insert for the 520 aluminum table. It wouldn't be too hard to come up with a design using an eccentric plug (as in the lathe tailstock) that allows both sisde-to-side and front-to-back adjustment to center the pins under the router.

But having worked with the overlaid composite table for about a year now, I've come to like it very much. Not only can I rout it and drill it to improve its capabilties, it's dead flat and smooth. A little wax and the workpiece just floats over the surface. If Shopsmith were ever to make another "stand alone" version of this tool again, such as I describe in https://forum.shopsmith.com/viewtopic.php?t=875, I would hope they simply attach the 520 trunnions to the composite table.

With all good wishes,

[rdonr]

Nick,

I'm sure the OPR table works fine. Just curious and looking for some insight into the design decision. So much about the ShopSmith is designed to be useful in multiple configurations I don't see how much is gained with a separate table for the OPR.

OTOH, the ShopSmith design has obviously been time tested and refined. Lots of little things on the machine show that it has really been thought about over the years. So maybe there was a particular reason for adding the OPR table.

In any case, I just got an e-mail that mine has been shipped so I'll be able to see for myself soon.

Please, Please quit doing those Sawdust Sessions. My bank account can't stand much more!

thanks,

don

[Nick]

Here's the engineering behind the Overarm Router table: It's smooth. The Shopsmith 520 table is ribbed to save weight, add strength, and make it easier to machine. The ribs also reduce the surface area that contacts the board when you're feeding wood across it. This reduces the friction and makes the operation easier.

The trouble is, these ribs are only oriented in one direction. This is just fine for about 99% of the woodworking operations you are likely to do on the Mark V -- ripping, crosscutting, molding, dadoing, shaping, disc sanding, even feeding a long board under the drilll press to create a series of holes. In all these operations, the work travels parallel to the ribs.

In routing, however -- particularly pin-routing and routing with a piloted bit -- the work must move in two dimensions. Sometimes it will be moving parallel to the ribs but most times it will move at an angle to them. There is a very good chance that the crisp edges of a freshly-planed board will hang up on the ribs during these operations, particularly if the board is slightly cupped or warped. This, in turn, may ruin the cut or cause you to lose control of the work. So, for your convenience and safety, and to help insure a good experience with our equipment, we provide a table designed soley for routing.

With all good wishes,

[Nick]

Here's the engineering behind the Overarm Rpouter table: It's smooth. The Shopsmith 520 table is ribbed to save weight, add strength, and make it easier to machine. The ribs also reduce the surface area that contacts the board when you're feeding wood across it. This reduces the friction and makes the operation easier.

The trouble is, these ribs are only oriented in one direction. This is just fine for about 99% of the woodworking operations you are likely to do on the Mark V -- ripping, crosscutting, molding, dadoing, shaping, disc sanding, even feeding a long board under the drilll press to create a series of holes. In all these operations, the work travels parallel to the ribs.

In routing, however -- particularly pin-routing and routing with a piloted bit -- the work must move in two dimensions. Sometimes it will be moving parallel to the ribs but most times it will move at an angle to them. There is a very good chance that the crisp edges of a freshly-planed board will hang up on the ribs during these operations. This, in turn, may ruin the cut or cause you to lose control of the board. So, for your conveniebce and safety, and to help insure a good experience with our equipment, we provide the table.

With all good wishes,

[charlese]

Although Nick's post doesn't need an encore - I'm going to give it one anyway.

Of course the OPR table is perfectly level. This is a MUST for a router table.

In addition:
When waxed - the OPR table is the smoothest, slickest surface I have ever worked on. By smoothest I mean workpieces slide smoothly. By slickest, I mean wood slides smoothly with very little resistance.

In more modern vernacular - you could just say - IT'S COOL!

[reible]

Hi,

It is interesting that now as part of the description for the Smithy or Harbor Freight version they have "Powerful OVERHEAD ROUTER" listed and in the specs they list "Pin Routing Capability"......... no sign of a special table for it or any details of how it is done.

Check it out at:
https://www.smithy.com/product_specs.php?cid=18&scid=19&pid=1003
and/or
http://www.harborfreight.com/cpi/ctaf/d ... mber=96067

Ed