Servicing a Crank Lock Out Tensioner

[R20190]

Does anyone know how to service a Crank Lock Out Tenioner head?

I have a Eagnas Smart 808 6-point machine that has gradually started to lose it's consistency. When calibrating the tension with digital scales, I find that one test to another the tension can vary up to 0.5lb now. Sometimes a little more.

The tension seems to vary particularly when I crank the tensioner quickly or very slowly. I have noticed that the string clamp plates are not holding the string as well as used to too.

I am wondering if anyone on here knows how I can service the tensioner and hopefully resolve some of the problems I am experiencing?

Many thanks for any help in advance.

This is the machine I have:

http://www.eagnas.com/jpg/sm808a1.jpg

[Mark A]

The tension seems to vary particularly when I crank the tensioner quickly or very slowly.

This is the nature of the beast with cranks, so it's not a calibration problem. The quicker you pull, the more the string will sag.

[R20190]

This is the nature of the beast with cranks, so it's not a calibration problem. The quicker you pull, the more the string will sag.

Thanks Mark, I did suspect this and have learnt to be more consistent when pulling. But I can't get my head around why this is.

Have you tried servicing a crank head and do you know how to make the gripper grip better? I've tried cleaning the plates but it seems it may be that the ball-bearings are shifting to one end and so the grip force is not as even.

[Mark A]

Thanks Mark, I did suspect this and have learnt to be more consistent when pulling. But I can't get my head around why this is.

Have you tried servicing a crank head and do you know how to make the gripper grip better? I've tried cleaning the plates but it seems it may be that the ball-bearings are shifting to one end and so the grip force is not as even.

I assume you've wound the limiter screw (back of the gripper plates, has a spring around it) all the way out. Failing this, there's not a lot to be serviced as far as the gripper plates go.

You could always take them apart and clean the faces with a toothbrush and rubbing alcohol - sometimes gunk can build up and impede grip.

[R20190]

I assume you've wound the limiter screw (back of the gripper plates, has a spring around it) all the way out. Failing this, there's not a lot to be serviced as far as the gripper plates go.

You could always take them apart and clean the faces with a toothbrush and rubbing alcohol - sometimes gunk can build up and impede grip.

Yeah I've done this already. In fact I had to wind that screw all the way out from day one. So it's pretty useless unless I string tennis/squash racquets. There ought to be more adjustment.

I thought there may be parts that need periodic tightening etc. No probs, thanks anyway!

[_Rav_]

You could try putting some tape with a reasonably abrasive surface (think masking tape rather than electrical, for example) on the gripper plates to give a little more traction.

[R20190]

You could try putting some tape with a reasonably abrasive surface (think masking tape rather than electrical, for example) on the gripper plates to give a little more traction.

I like it - thanks! But masking tape might wear out pretty quickly. I'll have a think.

[Mark A]

I like it - thanks! But masking tape might wear out pretty quickly. I'll have a think.

How about sandpaper? I've seen Kwun use it when he strung with that piano wire

[R20190]

How about sandpaper? I've seen Kwun use it when he strung with that piano wire

I guess very fine wet & dry sandpaper may work but wouldn't there be a risk of damaging the string?

[Mark A]

I guess very fine wet & dry sandpaper may work but wouldn't there be a risk of damaging the string?

If you compare it with how rough the gripper plates are, you should be absolutely fine.

An alternative is a folded business card, but the string will "scorch" a groove in it after a while and it will need changing.