Loctite

[marcros]

The rise and fall on my tablesaw consists of 2 gears at right angles to each other. This may be normal, I don't know. The shaft is steel and the gears look like some form of cast aluminium alloy. When I haven't used the rise and fall for a little while it gets very stiff. Tonight it snapped the roll pin holding the gear to the shaft- it had done this when I bought it too. It is a nightmare to get to this one- the top has to come off, motor probably out etc. I was expecting the shaft to be caked in dust but it seemed reasonably clean.

Now, would it be a bad idea to lock tote the gear to the shaft as well as putting a roll pin back in?

 

[Jamesc]

To snap a roll pin takes some pretty hefty torque the Locktite will help a little but I wouldbe worried that if the joint between the shaft an the gear in no longer the weak point the next weakest will go. This is very likly to be the teecth on the gears - a much more problematic thing to replace. I would be looking to see if there is anyway to prevent the problem in th future, perhaps a cover over the gears to help keep the crud out, or use a dry lubricant such a PTFE that won'ttrap the sawdust.

James

 

[marcros]

James,

In my heart of hearts, I was thinking along the same lines, although my fear was not being able to get the thing off if I needed to.

The strange thing is that the gears were pretty clean (they have a guard), and i had used ptfe lubricant the last time that i did it. I think that the issue is further up the shaft where the steel shaft passes through an alloy block which just seems to stick a little, although i did also lubricate this bit when I last did it. The roll pins were a really cheap set from motosave- i dont know whether there are varying qualities, and IIRC were metric versions of imperial sizes (3.2mm, 2.4mm etc). I wonder whether they were not the tightest of fits, and so it increases the shearing force by having a tiny amount of whip in the component.

The saw is french Kity, and from the 90's I think, so firmly metric.

Mark

 

[Jamesc]

Mark,

It does sound like the pins may be less than optimum shall we say. I was struggling to picture how you could exert enought torque to sheer the pin using a handwheel.
I can only suggest a good clean up and lubricate and replace the pin with a close fitting one. They can be a challenge to find, I will have a dig around in my collection if it helps , unfortunetely I won't have time untill the weekend.

Regards

James

 

[marcros]

thank you for the offer James but I will have a measure up and nip to Cromwell Tools. i could do with a few other bits too.

 

[woodfarmer]

You might want to clean and polish the shaft and the alloy bearing hole , then grease with molyslip grease. this is likely to stay slippery for some time. Check also that the slides can move, they were very stiff in my saw when I serviced it. had to take it all apart to clean them, now fine. but before was very difficult to raise or lower the blade.

 

[marcros]

i will try that, thanks.

 

[Spindle]

Hi

Make a replacement pin out of an appropriately sized drill shank, then secure it, (the pin to the shaft), with either Loctite or silicone sealer.

Regards Mick

 

[dickm]

Just a thought - the roll pin you used wasn't actually the type designed to be a weak point in something, was it? Quite a lot of agricultural machinery has shear pins at critical points, to protect other parts of the machine from damage if there is a blockage or similar shock load.

 

[marcros]

I don't think so Dick. When it broke both parts came out easily enough so I think it was just a loose fit. If I replaced it last time I didn't do a good job on it although I can't remember if I removed that gear or not.

I have some copper grease for use on brake parts. Will that do or do I need to go and buy some molyslip?

 

[Aden30mm]

My take is that Coppercrest is vastly superior to Molyslip.

 

[Hitch]

I think i'd be looking to see why it goes tight. If its the ally block, perhaps polish it all up a little and lubricate it, maybe even add in a hole/cup/nipple to allow proper lubrication.

Replace the roll pin with a new one, if there is room, see if you can put another smaller roll pin down inside of the first one.

 

[marcros]

I have almost finished this little refurb. I just have a cover to put in but ran out of time the other night. I also need a handful of m5 countersink screws which I may as well replace because the old ones are a bit tatty.

I believe that the cause was that ptfe lubricant, which I saw somewhere online previously, is just not suited to the task that I used it for. The leadscrew tool a lot of effort to remove on the bench, yet could be moved very easily when greased with moly grease and replaced. I replaced the roll pin and put a smaller one up the centre. I had actually done this with one of the two cogs before but not the other, if indeed I did it last time (I have a feeling that I didn't remove it last time). I also polished everything up the best that I could whilst it was in pieces.

It is annoying because i had already stripped it down to do the first time and so this last time has taken about 6 hours from start to finish. I didn't rush but am glad that I was not paying for somebody else to sort it.