Think I need Scrits advice?

[mailee]

My Elu 1251 radial arm saw seems to have a wobble on the blade. It has been like this for some time after hitting a knot and stopping! I decided to put a new blade on it and did this today. it still has some runout on the blade of about 1/32". I checked the blade with another one just in case I had bought a duff one but this too was out about the same amount. I checked the arbour as best as I could and it seems to be straight although I don't have a dial guage to check this with. (I used a piece of metal clamped to the motor housing and almost touching the arbour) When i replaced the inner flange and spun the arbour by hand it had the runout again. My question is could it be the flange that is bent or will it be the arbour? It is not a lot of runout but enough to make the blade wobble and give a wider kerf. A new flange is about £18 so I could replace this to try it but unfortunately a new arbour which is also the armature is around £82! I think I will put up with the wobble if this is the case.

 

[jasonB]

If you only have 1/32 at the edge of the blade the amount at the arbor will be too small to see by eye, you really need a dial gauge.

Just one other thing to check is that the blade is inline with the arm, if I get a big jam it tends to move the head and the back of the blade starts to rub/cut the side of the cut giving a wider kerf. May just be worth loosening off and resetting to zero.

Jason

 

[mel]

hi mailee
im due a visit sometime soon
you can borrow my dial gauge , magnetic base
this will let you know if the armature is bent
youve got my number to ring me
mel

 

[mailee]

Thanks Mel, was going to give you a call tonight, well I will actually. Speak later many thanks.

 

[Scrit]

Hi mailee

I'd go with Jason's suggestion of checking the run-out on the arbor with a DTI first. Personally I don't see you bending a 16mm or 5/8in arbor in a hurry, either. More likely that you've knocked the frame out of square (the sheet metalwork in the base of the smallet DWs is none too clever IMHO) so it'll be a case of doing a set-up from scratch. Have you got the manual?

Scrit

 

[mailee]

Hi Scrit and thanks for replying. Yes I do have the manual for it. I can't see how what you describe could manifest it'self in a blade wobble though? i just set up the saw on Sunday again as these as you know do go out of whack regularly. The other blade had been wobbling for a few months before this. I found that the vertical adjustment had moved slightly along with the 90 degree angle to the fence too. These are all corrected now. I have tried two other blades on it now and they both produce a wobble. I was just wondering after your reply if the rear flange could be buckled or indeed damaged in some way? I am going to borrow a dial guage from Mel tomorrow so I can check the arbour over the weekend. 1/32" is not much and I can put up with this for the type of cutting I do with it but I would like to get to the bottom of it as you can imagine. many thanks again for your help Scrit. :wink:

 

[les chicken]

Not being familiar with the saw but just trying to help.

Have you checked that there is not a bur or piece of rubbish stuck to the flanges somewhere. It would not take much to give the runout you are talking about.

Les

 

[mailee]

Well Scrit, I took your advice and I borrowed a dial guage from Mel and checked for runout in the machine. I first measured the runout on the arbour and just as you said there was none. The dial guage is very accurate and it didn't even move on iota! I then put the backing plate washer on and tried again, this time on the face of the washer/plate. Low and behold it was way out on the guage fluctuating around 50,000 of an inch! There is my problem it has somehow buckled the backing plate! I am happy with this outcome as this item is only around £18 compared to an armature which is around £85! and a total strip down of the machine. Thanks very much for your advice and a big thank you to Mel for the loan of the dial guage. At least now my mind is at rest and my wallet can breathe a sigh of relief.

 

[Scrit]

Well ..... ..... (I) checked for runout in the machine. I first measured the runout on the arbour and .... ....there was none. The dial guage is very accurate and it didn't even move on iota! I then put the backing plate washer on and tried again, this time on the face of the washer/plate. Low and behold it was way out on the guage

Glad that you found the cause! You had me an Mel going on that one, especially when we were chewing the fat on the blower! Did you notice whether or not the arbor back spacer is ally or steel? I've been told that some of the DWs now have ally ones. If it hadn't been that the next thing might have been to check the three bearings on the carraige in the arm to see if one had been loosened up by the shock - in fact that still might not be a bad idea.

Scrit

 

[Anonymous]

Always amazed by the in-depth knowledge of the participants on this forum.

 

[mailee]

Hi Scrit, The RAs I hacve is the Elu one and my back washer is a steel one I think as I can see slight radial lines on the rear of it where it has been machined. This is the reason I didn't originally put this part into the equation. It just shows how much force there must be on a blade while it is spinning and suddenly coming to a dead stop! I will check the bearings on the arm Scrit thanks, it doesn't do any harm and the more snug the running surfaces are on a machine like this the better the cut. Mel did explain to me the reasoning about the thin sheet steel base plate being suspect on these DIY tools campared to a commercial RAS. I didn't realise there were so much more beefy for the larger RAS. I am grateful to both you and Mel in helping me with the problem and glad it is repairable compared to having to buy a new armature. Mel did say you would be very surprised if the arbour had bent as this was very rare. Well you certainly know your stuff Scrit and I am very happy you do. Many thanks for the help mate.