Is a high level of vibration for a 'long hedge trimmer' normal?

[woody paul]

I have ran 3 tanaka pole hedge cutters and one of them is a killer to your hands with vibration. Had to have new crank bearings under warranty as they had play in them still no difference. It runs OK so just use it with a good pair of gloves. 

[Bolt]

23 minutes ago, adw said:

If it’s  vibrating badly at idle then it is nothing to do with the gearbox or shaft as these are not moving at idle, so maybe imbalance in the centrifugal clutch?

 

 

 

Certainly, but It’s also not inconceivable the shaft may be moving at idle if the clutch is shot.

 

I see no harm in running the engine unit in isolation.

 

Of course, it’s an eBay purchase with unknown history….

 

….it could have all the faults.

 

 

[pleasant]

Greasing/lubricating will not make any difference. Something is imbalanced- like someone has said, run it without the attachment fitted in the first instance. This will give you an idea as to where to isolate the issue to some degree. The km56 power unit uses a flexi driveshaft, so is unlikely to be 'bent' in the true sense of the word, but the ends can get crimped to a degree. They are easy to remove and check- 8 torx screws and the top body comes off and the shaft just slides out. Fiddly, but no special tools required. When you run the power unit observe the rotation of the end of the shaft where you connect the attachment. You should clearly see whether it is off  centre.There should be two metal 'bows' in the end of the shaft to help locate the corresponding shaft on the attachment....these can break and if they shear off in the end of the shaft then a new shaft end is required and they are expensive. The hedge cutter attachment does have a solid shaft with support bushes/nylon sleeve, but unless the shaft has been removed, bent then put back in during normal use I have never known one to simply bend. Bushes/support sleeves can deteriorate. Is it a genuine stihl attachment...I have seen loads advertised with a stihl power unit and an generic attachment....had one in a few weeks ago with exactly that, there was intermittent drive to the head.....turns out it was an ebay purchase and the seller had tried to shorten the drive shaft on the generic head to get it to fit.

 

If you do decide to remove the power unit top cover (assuming it still vibrates with no attachment fitted) then while you're in there check the flywheel fins..if one is missing this will give to bad vibrations...as it also will if it is loose, but a loose flywheel probably won't allow it to start in the first place

Edited November 10, 2022 by pleasant

[Stere]

They are quite bad for vibration when new compared to some other multi tools but maybe not "that" bad.  Seem very similar to using the titan screwfix ones with regards to  having crappy anti vibes.

 

 

 

The bigger engines ones in the range are abit better than that model but still not very good.

 

 

 

The husky multi tool engine unit is noticably  better  and nicer to use - less vibrations than the stihl models.

 

 

 

[Trailoftears]

I would check the specs for that particular machine via the current stihl catalogue.Also,if its a kombi,I suspect you will get more vibration due to the extra joint.But no-no way should it feel unpleasant in normal use frankly.

[Trailoftears]

Having had a brief look thru the stihl catalogue re:vibration levels,apart from their insanely huge ms881 chainsaw-120cc engine,and also their cheapest nastiest strimmer-fs38,your machine is pretty awful re: vibration levels sadly,and thats without considering any extra issues that may exist.If you're just using the machine for say 15 minute sessions 2 or 3 times a week-not a big issue.But should you be using it for extended periods in a business styley-get rid.It will do you quite serious nerve ending harm over a couple of seasons I fear.

[greenant88]

Update:

 

Thank you for everyone who replied. I took said stihl combi to a local garden machinery mechanic who diagnosed that the shaft of the trimmer attachment wasn't sitting fully into the motor housing due to some bent pins and the collar of the housing having moved forward which was stopping it properly aligning. 

 

He assured me that the vibration levels are now normal after moving the collar and re aligning the pins(and he said even better than the usual compared to other similar models) and also said he took apart the clutch and other parts to fully check it over.

 

He did also said that the Stihl KM 56 RC is generally more of a residential model compared to that of a more expensive pro model which has some additional dampeners inside (which helps people using them for hours a day).

 

It appears at first glance to be much much better vibration wise after his work, although some vibration is expected - and now able to use it for work the next situation that arrises.

 

Thank you

Edited November 24, 2022 by greenant88

[Stubby]

9 hours ago, greenant88 said:

Update:

 

Thank you for everyone who replied. I took said stihl combi to a local garden machinery mechanic who diagnosed that the shaft of the trimmer attachment wasn't sitting fully into the motor housing due to some bent pins and the collar of the housing having moved forward which was stopping it properly aligning. 

 

He assured me that the vibration levels are now normal after moving the collar and re aligning the pins(and he said even better than the usual compared to other similar models) and also said he took apart the clutch and other parts to fully check it over.

 

He did also said that the Stihl KM 56 RC is generally more of a residential model compared to that of a more expensive pro model which has some additional dampeners inside (which helps people using them for hours a day).

 

It appears at first glance to be much much better vibration wise after his work, although some vibration is expected - and now able to use it for work the next situation that arrises.

 

Thank you

Thanks for the up date . Some would not bother once they were sorted .

[Trailoftears]

Glad you've sorted it out.Depending on usage,may be a plan to treat yourself to a pair of anti vibe gloves-gel-filled palms/fingers.It does have a highish vibe rating.The higher you up the food chain/spend,the more effort is devoted to a.v.It seems.

[scbk]

2 hours ago, Trailoftears said:

Glad you've sorted it out.Depending on usage,may be a plan to treat yourself to a pair of anti vibe gloves-gel-filled palms/fingers.It does have a highish vibe rating.The higher you up the food chain/spend,the more effort is devoted to a.v.It seems.

From the HSE re "anti vibe" gloves:

Gloves marketed as "anti-vibration", which aim to isolate the wearer's hands from the effects of vibration, are available commercially. There are several different types, but many are only suitable for certain tasks, they are not particularly effective at reducing the frequency-weighted vibration associated with risk of HAVS and they can increase the vibration at some frequencies. It is not usually possible to assess the vibration reduction provided in use by anti-vibration gloves, so you should not generally rely on them to provide protection from vibration. However, gloves and other warm clothing can be useful to protect vibration-exposed workers from cold, helping to maintain circulation.