I'm doing a cleanup / restoration of an old Art 4.A Sigma cutter and it's missing the top screw in the handle (Yellow Arrow in image) Handle part number is # Art 24AE I can see on the part image it is a hex screw. Without this screw the 10mm cutout slot in the cutter handle just drags along the top of the bar.
Also there's another lower hex screw behind the scribing wheel (Red Arrow in image) that has a round metal collar that is worn flat and won't spin freely. (second image) Is that where the replacement bearing goes ?
Does this model handle have two identical bearing that run along the top and bottom of the bar ?
Help please, so confused.
UPDATE ***
I found a Sigma pamphlet with a similar handle that points to the top screw and says "This handle is equipped with a system for the recovery of wear from sliding on the guide"
Can somebody with a similar model Sigma please remove the top screw and solve this mystery?
Anybody willing or able to post a pic of this screw and any part that may be inside ?
UPDATE 2***
Solved on Reddit > the upper screw is literally just a screw of the exact same dimensions as the screw that holds the Bearing. It tightens to pinch some of the slop that is developed over time by the handle slot getting worn and riding on the rail. To get the missing bolt I just ordered a replacement ball bearing so I have an extra thru bolt.
But it is somewhere in the range of a partially threaded M5 x25mm (with 15mm smooth shoulder and 10mm threaded) Socket Head Cap Screw. It's a bit of a strange beast - due to the proportions of threaded and non threaded shaft. The easy solution is just to order a Bearing that comes with the screw. A workaround hack would probably be to order a M5 x30mm that is half threaded and half smooth and then trim it by 5mm so you get the right about of thread and length.
Also there's another lower hex screw behind the scribing wheel (Red Arrow in image) that has a round metal collar that is worn flat and won't spin freely. (second image) Is that where the replacement bearing goes ?
Does this model handle have two identical bearing that run along the top and bottom of the bar ?
Help please, so confused.
UPDATE ***
I found a Sigma pamphlet with a similar handle that points to the top screw and says "This handle is equipped with a system for the recovery of wear from sliding on the guide"
Can somebody with a similar model Sigma please remove the top screw and solve this mystery?
Anybody willing or able to post a pic of this screw and any part that may be inside ?
UPDATE 2***
Solved on Reddit > the upper screw is literally just a screw of the exact same dimensions as the screw that holds the Bearing. It tightens to pinch some of the slop that is developed over time by the handle slot getting worn and riding on the rail. To get the missing bolt I just ordered a replacement ball bearing so I have an extra thru bolt.
But it is somewhere in the range of a partially threaded M5 x25mm (with 15mm smooth shoulder and 10mm threaded) Socket Head Cap Screw. It's a bit of a strange beast - due to the proportions of threaded and non threaded shaft. The easy solution is just to order a Bearing that comes with the screw. A workaround hack would probably be to order a M5 x30mm that is half threaded and half smooth and then trim it by 5mm so you get the right about of thread and length.
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