Photo Index - Duro Metal Products Co. - No. 3100

Machinery Photo Index

Manufactured/Badged by:
Duro Metal Products Co.
Chicago, IL.

Machine Specifications
Machine Class:	Wood Working Machinery
Machine Type:	Overarm Router
Machine Size:	1/4" & 1/2" Bits
Submitted By:	Keith Bohn

Machine Specifications
Description/Model:	No. 3100
Date of Manufacturer:	40's
Serial Number:
Last Updated	11/13/2005 3:44:14 PM

Comments:

The short story on finding this one was it came up on Craig's List. It was advertised all the way from Minneapolis to Grand Rapids. The machine was located in Chicago. To make the long story as short as possible I saw it as did OWWMer Marty Phee. The seller needed it off the premises (lost lease) by the end of the month or it was going into the dumpster. Neither Marty or I knew the other was sniffing it and Marty being closer/faster/stronger beat me to it. Somehow though I knew it would be coming back to me and it did. Thanks Marty.

The Duro No. 3100 was officially called a High Speed Production Router Carver-Shaper. It was to the best of my knowledge first available some time around the 40's but could have been available prior to that. I don't know. It originally sold for $150.

The machine weighs around 200 lbs. With the table and over arm/motor removed one man can handle the trumpet style base though it's not a whole lot of fun.

According to the literature the motor is a General Electric Universal Motor. No horsepower is given though the dirty paper tells us that it draws 1200 watts "at the spindle" and goes on to mention that, "746 watts equals one horse" which is true but inefficiencies aren't taken into account so you make up you own mind. On the machine I have the motor is tagged as 6 amps. By my math that makes the motor a strong 3/4 horse. Again, you make up your mind.

The machine consists of the trumpet shaped base, a two piece table and table bracket, a casting that sits atop the base, a horizontal arm with the router motor and all the various knick-knacks to hold it all together and make it function.

Coming from the base is a foot pedal that controls the up and down movement of the table. The maximum up and down is around 1 7/8". When the base is fully depressed it can be slid to the right where it can catch underneath a small piece of steel there. I have yet to convince myself that it won't vibrate free from there and have the table come crashing down. This will definately require some looking at.

The table bracket can move up and down the column for gross adjustment and there are two stops along the left side to set maximum height and where the bracket will stop when at rest. The table is somewhat adjustable to the bracket I'm guessing to allow for aligning the table to the motor for say when you have a pin in the table or even for shimming square to the cutter. In addition to all of this the table bracket is threaded to allow the motor to be slung underneath and used as a shaper. A gib on the right side takes up play between the bracket and the base column. All in all the table isn't the smoothest thing but workable.

The table itself has two tapped holes behind the cutter opening for a fence. I did not get the fence with this machine. Flanking the cutter opening are two more holes for starting pins. Forward of the cutter opening hole (near the miter slot) are three more tapped holes. At first I thought these were user added but the surface underneath the middle hole is machined (seated) making me think it was a factory touch. Oddly the miter slot is only 5/16" deep. That's OK, I prefer to make my own miter gages.

The over arm fits into a casting that sits atop the column base. There is no scribed line along its length so there is no way to make alignment when the over arm is slid in or out. It would only require making a scribe line and corresponding marks on the castings which I think I will do. It is 12" from the center of the collet to the face of the column with the arm fully extended.

The drive unit consists of a motor similar to a c-face motor and a spindle nose. These came to me in very good cosmetic shape but of course they need new bearings. I can see two bearings in the spindle nose. Both are New Depature (C-88504 and C88501) which are both available from Fafnir (204KLL2 and 201KLL2 respectively). There are two additional motor bearings which I have not been able to ID at this time. The switch on the motor looks to be pretty solid.

As best as I can tell this machine has always been blue. That or someone has done a pretty good job of re-painting.

Fast forwarding through history, Duro continued to make this machine for a number of years. Over the years the trumpet base gave away to a sheet metal box that sat underneath a casting that the table attached to. Atop this casting was a vertical column that allowed for the drive unit to slide up and down (a nice change). Atop this column went another casting that accepted the over arm and to that was attached the drive unit. When all of these changes were made I do not know.

The design was bought by Rockwell and it first appeared in the 1971 Rockwell/Delta catalog. These were sold as model numbers 43-502 (single phase 115 volt) and 43-503 (three phase 230 volt). From the looks of it the drive unit for these machines are the same as used by the earliest Duros (as shown here). Rockwell brags "develops a full 2HP".

It is a rather diminutive machine and only stands 54" at the top of the motor. In all it doesn't even compare to nearly every over arm router made but it has an endearing funkiness to which they lack. My intentions are to replace the bearings, check the motor over real good, replace the brushes and put it into service where I hope it will work fine up to the day it will be taken from service.

Additional pictures are available should you need them.

Photo 1:

Comments: Duro 3100 High Speed Production Router Carver-Shaper
Source: Keith Bohn

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Photo 2:

Comments: Motor Close Up
Source: Keith Bohn

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Photo 3:

Comments: Table From Below Showing Aux. Spindle Nose In Place
Source: Keith Bohn

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