Saturday, December 6, 2014

Upgrade Cowboy CB3200 Edge Guide - Modification

Upgraded Edge Guide

I was having a real problem with the Cowboy CB3200 edge guide.  I believe it was designed for the CB4500 which has a slightly different casting in the cylinder arm.

The problem:
The thumbwheel tightens from the bottom and the thumbwheel comes into contact with the cylinder arm casting which limits the edge guide to about 1/2".  I usually set my edge stitching from 1/4" - 5/16".  The edge guide comes with a wing nut which allows for a closer setting, but is extremely hard to tighten; one of those things that you need three hands for and it also hits the cylinder arm casting.

The Solution:

Replace the threaded post and thumbwheel.

Replacement Parts:

T-Slot Bolt (M6X1 Thread), 5/16" washer, thumbwheel (M6X1 Thread)

Bronze sleeve bearing (1/4" ID, 3/8" OD, 1/4" Length).  You will need to lap the bushing from 1/4" to 21/128".  I used 80 grit sandpaper. This took about 10 minutes.


3/8" hole is too large for new T-slot bolt which allows too much play.

 After lapping the sleeve bearing, tap it into the 3/8" hole until it is flush top and bottom.

Place the spring washer in its original position.

The 5/16" washer was one that I had and it fit inside the stepped hole (slip fit).  It compresses the spring washer when the thumbwheel is tightened.

Insert the T-slot bolt from the bottom through the slotted keyway and thread the thumbwheel from the top.  The T-slot bolt has a flattened side which rides along the keyway and keeps the bolt from turning when tightening the thumbwheel.

Note that the guide bearing can be adjusted right up to the front walking foot without the T-slot bolt hitting the cylinder arm casting.

I also added a washer above the guide bearing to reduce the clearance from the needle plate to the bottom of the bearing.  This helps keep thinner materials from sliding underneath the bearing.

I couldn't find a 1/4-28 threaded T-slot bolt so the 6 mm - 1 pitch was substituted.

Parts Source:

  • 2868T1 - Bronze Sleeve Bearing, for 1/4" Shaft Diameter, 3/8" OD, 1/4" Length
  • 92770A111 - Machined Neck T-Slot Bolt, M6X1 Thread, 25MM Long
  • 90368A300 - Stainless Steel Round Knurled Thumb Nut, M6X1 Thread, 24MM Head
  • I had the 5/16" washer 

Works perfectly now and is very easy to adjust.  Total cost: about $25.  The guide can be swung 180º and left on the machine for normal sewing.

Hope this helps,

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