Mitre Saw - what's going on with the cuts its making???

[Russ69]

I've recently changed the blade on my Bosch compound mitre saw, and have just seen the problem with cuts shown in the attached image; as I pull the blade down and onto the wood, the first part of the cut appears to be poor - wider than the rest of cut as I push the saw across the wood. The remainder of the cut as you can see is fine, its the first part of the cut that has some problem. Any ideas?

The pic shows the two pieces of wood pushed together after the cut has been made, and the problem is obvious. What's causing it???

Thanks!

 

[novocaine]

it looks like arbor wobble. once it's in the wood it's stablised by the wood, before that it's dancing around. check the bearings in the motor and that you've centered the blade correctly and tightened the nut.

 

[transatlantic]

Is this a sliding mitre saw?

Sounds like there maybe a little slop in the mechanism, which is causing a wobble saw effect due to vibration.

Slide the saw to it's maximum point and check for play. It should be barely noticeable

 

[Russ69]

Yes its the PCM 8 sliding saw - cheesed off its the saw rather than the blade as its not had that much use since I bought it (just out of warranty too). I'll check the blade mounting, but if its the saw itself not sure what I'm going to be able to do resolve it?

Is this a sliding mitre saw?

Sounds like there maybe a little slop in the mechanism, which is causing a wobble saw effect due to vibration.

Slide the saw to it's maximum point and check for play. It should be barely noticeable

 

[transatlantic]

Yes its the PCM 8 sliding saw - cheesed off its the saw rather than the blade as its not had that much use since I bought it (just out of warranty too). I'll check the blade mounting, but if its the saw itself not sure what I'm going to be able to do resolve it?

Is this a sliding mitre saw?

Sounds like there maybe a little slop in the mechanism, which is causing a wobble saw effect due to vibration.

Slide the saw to it's maximum point and check for play. It should be barely noticeable

Hopefully something is just a little loose

 

[transatlantic]

Also - try making the cut without sliding (there is usually a screw to clamp the saw assemlby to the rails) and see if it does the same. If not, then it's most likely what Novocaine suggested.

 

[Russ69]

Thanks for the suggestions guys - in addition to the above I think I'll;

1) Try re-seating the existing blade.
2) Replace the current blade with the original and see how it compares.

 

[JSW]

Try dropping the blade into the timber by a couple of mill while in the closed position, then extend it through the timber (IE: From the closed position to extended), in effect making a scoring cut, then drop the blade fully through the timber and make the cut (IE: Extended back to closed)

 

[YorkshireMartin]

I had this exact problem with my Bosch saw when new. I have the GCM8 SJL.

What blade did you buy to replace the (utter rubbish - mine went in the bin) standard one?

 

[rafezetter]

Can't help with the cuts but if the warrenty expired less than a year ago and it's the saw mechanism that's gone sloppy you've got a solid argument for a replacement.

Sale of goods act requires that all goods be "fit for purpose" and for a longer period than most manufacturer warrenties - up to 6 years point of fact. If you can show it's had little use and not been used as a professional every day workhorse, you've definitely got good reason to contact Bosch.

 

[GeordieStew]

Can't help with the cuts but if the warrenty expired less than a year ago and it's the saw mechanism that's gone sloppy you've got a solid argument for a replacement.

Sale of goods act requires that all goods be "fit for purpose" and for a longer period than most manufacturer warrenties - up to 6 years point of fact. If you can show it's had little use and not been used as a professional every day workhorse, you've definitely got good reason to contact Bosch.

If bought after Oct 2015, Sale of Goods Act no longer applies.

http://www.which.co.uk/consumer-rights/ ... -goods-act

 

[Lons]

I'd check the blade very carefully as some of the cheaper ones can have significant wobble, especially if thin kerf, I had exactly that with my DeWalt when I used cheap blades.

 

[transatlantic]

Did you sort this? My mates saw is doing the same thing. I've triple checked everything is right and square. No real sign of slop, so assuming blade as it's the stock one

Sent from my SM-J510FN using Tapatalk

 

[Lons]

Did you sort this? My mates saw is doing the same thing. I've triple checked everything is right and square. No real sign of slop, so assuming blade as it's the stock one

Sent from my SM-J510FN using Tapatalk

Tell him to get a lump of hardwood and watch the edge of the blade very carefully as it starts the cut, a bright light helps. If the blade "flutters" then throw it in the bin assuming as you said all else is as should be and the blade is sharp.

It's happened to me on my DeWalt and also can happen with a cheap blade on a Stihlsaw, a decent sharp blade doesn't do that.

Bob

 

[transatlantic]

Did you sort this? My mates saw is doing the same thing. I've triple checked everything is right and square. No real sign of slop, so assuming blade as it's the stock one

Sent from my SM-J510FN using Tapatalk

Tell him to get a lump of hardwood and watch the edge of the blade very carefully as it starts the cut, a bright light helps. If the blade "flutters" then throw it in the bin assuming as you said all else is as should be and the blade is sharp.

It's happened to me on my DeWalt and also can happen with a cheap blade on a Stihlsaw, a decent sharp blade doesn't do that.

Bob

sorry - what do you mean by watch the blade? it's a blur?

 

[Lons]

Did you sort this? My mates saw is doing the same thing. I've triple checked everything is right and square. No real sign of slop, so assuming blade as it's the stock one

Sent from my SM-J510FN using Tapatalk

Tell him to get a lump of hardwood and watch the edge of the blade very carefully as it starts the cut, a bright light helps. If the blade "flutters" then throw it in the bin assuming as you said all else is as should be and the blade is sharp.

It's happened to me on my DeWalt and also can happen with a cheap blade on a Stihlsaw, a decent sharp blade doesn't do that.

Bob

sorry - what do you mean by watch the blade? it's a blur?

It's not actually. You need to look at it from the front straight on to the cutting edge and any slight side to side wobble or fluttering can be seen quite easily. If you're scared of it then set up a video camera!

I'd add a note that I have no idea whether it's normal practice to do that and you clearly have to be carefull, wear safety glasses and keep body parts well away that said, it does work - I've done it several times and binned the offending blades both on my saw and my stihlsaw.