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Model-Building Workshop - CNC Rotary Table for Sherline Mill

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Overview

In May 2005, I ordered and received a Sherline 3700-CNC Rotary Table and 3702 Right Angle Adjustable Tailstock from The Sherline Shop. I plan to use these to do continuous and indexed 4-axis milling on my Sherline CNC Mill

To refresh your memory, or in case you haven't seen my Tooling Plate Page, below are a few shots of the tooling plate onto which the Rotary Table will be mounted. The four holes closest to the left end of the Y axis allow direct attachment of the rotary table from the bottom, without any additional plates or adapters. This frees up a lot of milling room!

Tooling Plate Pete Brown, April 2, 2005

Tooling Plate Pete Brown, April 2, 2005

Tooling Plate Pete Brown, April 2, 2005

Motor Adapter / Mount

In order to use it with my Desk CNC system, I needed to make a motor mount that would adapt from the Sherline NEMA 23 to the odd spacing found on the Globe Servomotor. I don't think that a reducer belt assembly would fit in that space. If it did fit, it surely would be tight.

I designed the mounting adapter in AutoSketch, created the toolpaths in DeskCNC, and milled it using a 3/32" carbide bit. The material I chose, simply because I had some, was 1/2" thick UHMW plastic. This plastic is reasonable to machine, and is pretty strong for a plastic. I found it to be strong enough for this application, anyway.

Motor Mount Pete Brown, May 6, 2005

The CAD files, in DXF and AutoDesk AutoSketch 9 format, are available for download here. The motor specs from Globe, in PDF format, are available here.

CNC Milling

Preparation Preparing to fly cut the material down to 3/8". I only fly cut one side to make support easier.Pete Brown, May 6, 2005	Motor Mount Side A has been milled. I have fliped to side B and registered. Registration was done by eye with the end mill. Pete Brown, May 6, 2005	Motor Mount The final step: cutting out the mount. I paused the NC and slipped an aluminum support in while this was cutting.Pete Brown, May 6, 2005
Motor Mount Here you can see the 1/2" aluminum support I forgot to put in when this started. This was possible because I only fly cut the one side. You can get a way with a lot with plastic and small cutters. Pete Brown, May 6, 2005

The Finished Piece

Motor Mount - Side A This side contacts the Sherline mount. Pete Brown, May 6, 2005

Motor Mount - Side B This side contacts the motor. Pete Brown, May 6, 2005

Installation

Motor Mount Lowes had no #6-32 SHCS, so I had to use these. The holes were countersunk for the SHCS, so they are deeper than was necessary. Pete Brown, May 6, 2005	Motor Mount The 3/8" thickness leaves barely enough shaft for coupling. 1/4" would have been better, but I was concerned about strength. Pete Brown, May 6, 2005	Motor Mount Installed. It fit perfectly the first time! I used 3/4" 8-32 SHCS a washer and lock washer on each corner. Pete Brown, May 6, 2005
Motor Mount Here you can see the minimal clearance between the two motors. I would have preferred to angle the cables downward, but they won't clear the other motor if I do. Pete Brown, May 6, 2005	Table Mount The Sherline Rotary Table attaches to the tooling plate with four SHCS screwed in from the bottom. Obviously this must be done before mounting the tooling plate. Pete Brown, May 7, 2005	Table Mount Here you can see how the Sherline Rotary Table attaches to the tooling plate. The stand-offs are provided with the plate. Pete Brown, May 7, 2005

DeskCNC Rotary Table Setup

The Globe motor is a 500 steps per revolution motor. Per the Sherline documentation, the Sherline rotary table moves 5 degrees for every revolution of the handwheel/motor. Therefore, the steps per degree to enter into DeskCNC is 100. Make sure you have the table set up as rotary, not linear, and that you do not have it slaved to any other axis (unless you want it that way, and you know why you have it slaved)

Rotary Table In-Use

Rotary Table This is a test setup with a piece of scrap ABS rod. Pete Brown, May 7, 2005

( Coming soon! )

If you found the information on this page useful or interesting, please take a moment to sign my guestbook. Thanks!