Excessive Vibration? Check the counterweight alignment.

I recently serviced a Handi Quilter Forte longarm quilting machine with a Pro-Stitcher for its first service- it was less than a year old (but had well over 10 million stitches on it) so it had not been opened since assembly at the factory.

The customer is a professional longarmer with two other longarms so she knows what she is doing. Since the machine had been in operation, it had always vibrated more than the other two longarms, particularly at certain SPM speeds, and the vibration would cause multiple thread breaks per quilt even with perfect tension.

Before disassembling the machine I ran it with no thread in it for a few hundred stitches but did not see, feel, or hear anything abnormal. All the exterior checks of hook movement, handwheel spacing, and cable location all looked good.

After opening I checked the belt tension and rotated the handwheel several times. After referencing the tech manual I notice that the counterweight was not in alignment with the Pitman Crank - about 8 degrees off - see picture 1.

The alignment procedure instructs to rotate the needle shaft until the Flat of the Pitman Crank is vertical, and then loosen and rotate the Counterweight until the split is also vertical. I could have eyeballed it and probably gotten it close enough, but since I had a leveling laser handy (picture 2A/2B), I set the laser up to increase the accuracy.

If you are a longarm technician and don't have a laser don't fret, eyeballing is pretty good, and I bet you know someone that has a laser as a handyman or painter that you could borrow - they are around $100 and many put out both a horizontal and vertical line.

I first used the laser to get the Pitman Crank Flat vertical (picture 3).

I then placed the laser on split of the Counterweight, loosened it, rotated until it was vertical, (picture 4) and then firmly tightened the fasteners with a hex wrench.

The machine was then re-assembled, tested, and the customer noticed it was much smoother and quieter.

For the first time since owning the machine she was able to completely stitch out multiple quilts without the thread breaking - and told me "the machine feels brand new"!

I have been inside a couple-hundred longarms and this is the first time I have seen this issue. I also asked several Longarm tech friends if they had seen, and none of them had so the issue is apparently pretty rare - but if your machine has excessive vibration this is a great place to start.

Quilt On!