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Manufactured/Badged by:
Rockwell Manufacturing Co.
Pittsburgh, PA

Machine Specifications
Machine Class: Wood Working Machinery
Machine Type: Grinder, Bench
Machine Size: 7" wheel, 2" wide belt
Submitted By: JB Lenzi
Machine Specifications
Description/Model: 23-570 Combo grinder-sander
Date of Manufacturer: 1973
Serial Number: 157-9632
Last Updated 1/6/2008 12:52:02 AM

I've been looking for one of these for a while. It's a standard Delta-Rockwell 7" grinder with an attachment on one end to drive a 2" x 48" abrasive belt.

These combo grinder-sander units were introduced in 1973, not long before this one was made, and they lasted into the Pentair era, until Pentair/Delta International stopped selling US-made grinders. They were available on the 7" and 10" grinders as the combo unit seen here, and also as a dual-belt unit on the 10' grinder motor. In the Pentair years, they were mounted on Wissota-made grinders instead of the original Marathon-built type.

This one was in very original conditon but needed a little TLC to make the belt track well and to reduce vibration overall. It didn't help that they had the belt on backwards (running the wrong direction for the splice), but the primary vibration problem was with the flange washers for the grinding wheel.

Late 1973, when this unit was delivered, was right on the cusp of the Rockwell International "Sign of the Devil" years, and it's sort of obvious with this unit that some corner-cutting was already taking place in Bellefontaine. Aside from the flange washer problems, the motor itself was never mounted squarely to the base, and the base casting is a little rough compared to earlier vintage 7" grinders. The mounting of the wheel guards for the belt leaves a little to be desired too, as the draft on the castings makes it difficult to clamp the guards firmly in place. Still a very functional machine once a few things were tweaked.

The belt unit can be rotated to any angle for use, and the lower belt guard can be removed so that curved objects can be placed directly against the lower wheel if desired.

It's mounted on one of Rockwell's better ideas--the steel/cast-iron pedestal base modifed from earlier all-cast-iron bases to accept a Furnas LVC magnetic starter with 24V coil, so all controls are self-contained in the pedestal. The older cast-iron stands would accept manual motor starters inside, but not magnetic ones.

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