My new toy

[ChrisR]

Martin.

A the last place I worked as site electrical engineer, there was a lot of production machinery, the machinery maintenance engineers had round plastic belting in large coils/lengths, which they would cut to required length, then would heat the ends with a large soldering iron and butt joint them together, these belts would then be put into service, on a machinery which was running 24 hours a day, so it was very serviceable/strong.

If you look on the Chronos web site, under (plastic transmission belt), I think this must be the same or similar product.

Hope this is of help.

Chris R.

 

[martinka]

scrimper, the two belts are identical sizes. If I swap them over I get the same effect. The bolt above the motor secures the end of the counterweight. (I'd like to find out about the later counterweight) I'll check the motor mounting holes to see if I can get any slight movement but I suspect the problem is simply old belts that haven't been used for a long time. Belts will take a slight set if not used for a long time and the fast speed of the motor pulley will show this up, The final drive pulley is turning something like 9 times slower.

I could remove the accessory pulley and have a saw running at something like 6000SPM :shock:

Chris, thanks for the tip. I knew, but had forgotten about, the plastic belt as it is used on a small drill I have been thinking about building for far too long. There's another type that is hollow and uses a tiny aluminium piece to connect the belt ends. I don't know how effective either would be on a motor this fast.

 

[scrimper]

The bolt above the motor secures the end of the counterweight. (I'd like to find out about the later counterweight)

Be interested to see what that counterweight looked like mine was just a lump of metal with a hole where the shaft runs through and held with a grub screw, I presume yours is a later model than mine?

 

[martinka]

I'm confused now because I thought mine was an earlier model. I saw an old post somewhere which mentioned an arm for the balancer, which mine has, and he said Mr Woodward told him it could be updated for £50. I just found a price list, not sure when from, and it mentions a vertical balancer and that a £1 coin can be stood on the table at any speed. It certainly can't on mine.

I've just been to take a photo of the balancer and noticed the the Pitman arm from the balance arm to the drive shaft was slightly loose. I experimented moving the arm round on the shaft and the vibration is much lower now, though I am sure a £1 coin still wouldn't balance on the table.

The balance/counterweight is the long black arm which fastens at the back of the saw and to the arm visible at the front behind the pulley. This arm like a cam and the black arm moves up and down. I assume this is the vertical balancer referred to in the price list.

Out of interest, mine was £585 when this price list was up to date.

 

[ChrisR]

Martin.

I think these heat join belts were reasonably tough. I know a lot were just running indexing drives/counters, but others were used as drives for small/short conveyers, and all were running 24 hours a day.

To join the belts, the engineers had modified a large electric soldering iron. The copper end bit had been hammered out until it was only about 3mm thick, they would hold the two cut ends either side of the bit, when it started to melt, the ends were just slid together and held for maybe thirty to forty seconds to cool.

The modified soldering iron bit, always reminded me of a duck billed platypus, but then I have a very strange mind. #-o

Take care.

Chris R.

 

[martinka]

The urethane belt might be better, because what is happening is that the elasticated belt is being stretched by centrifugal force and throwing it off the pulley, but I don't know why. It obviously wasn't designed that way. I'm tempted to slot the holes for the motor just to see if a bit of adjustment will cure it. On the whole, it doesn't really matter as it happens at full speed, whereas at around 900SPM, where the saw seems most comfortable, it isn't a problem.

Martin.

 

[mjcann]

In my experience, slack on the off side of driving pulley has been caused by the load being higher than design, belt stretches on pull side therefore tension is destroyed, so it may be advisable to check free movement of parts.
Martin

 

[martinka]

The motor and accessory pulley spin freely, and the belt(s) still exhibit the same behaviour without the final drive belt coupled up. I did consider the notchy bearing on the counterweight, until I disconnected it and it made no difference. Although they feel OK, I think I'll have the accessory bearing apart anyway to check it and might also strip and make sure the motor is clean and lubricated. Thanks for chipping in: the more heads, the more chance of solving the problem.

 

[scrimper]

That balanced is way advanced to mine, yours must be a much newer model.
I have to say that without a balance weight mine runs smooth enough, not as smooth as the Hegner but I put that down to the Hegners slower running induction motor.

 

[scrimper]

This is the size of a new white spot belt, you can compare it to your belts?

When they are new they are very tight, are you sure that yours isn't too stretchy?

 

[martinka]

I'll check in the morning, but it takes very little stretch to make a difference and I suppose it's possible the belts haven't stretched but have lost their elastic strength, if that makes sense. I have noticed that the first belt seems slacker than the 2nd, but swap them around and it's just the same. Without any adjustment, there's nothing I can do about that.
Cheers,
Martin.

 

[scrimper]

I suppose it's possible the belts haven't stretched but have lost their elastic strength, if that makes sense.

TBH That is what I meant but could not find the right way to describe it that you have done.

 

[martinka]

This is the size of a new white spot belt, you can compare it to your belts?

When they are new they are very tight, are you sure that yours isn't too stretchy?

I just measured mine the same way and though they are the same length as each other, mine measure 11.25"
I found an old washer shop fairly local to me so I'll give them a bell this morning. Looks run down and still has half day closing on Wednesday, so there's a good chance of old stock.

Martin.

 

[ChrisR]

Martin.

May be worth looking on this site, for belts.

http://www.espares.co.uk

I have just used them for a pair of motor carbon brushes.
Very good service.

Take care.

Chris R.

 

[scrimper]

They do sell a Hotpoint belt that will fit the Diamond however they charge £12.99 + £2.99 postage for it which IMHO is well over the top. a quality belt can be found on ebay for £6.99 inc free postage.

TBH Having been in the trade for most of my life I am quite amazed at some of the prices these online sellers charge!

 

[martinka]

I'll probably go for the one on ebay (I just did) as I am convinced it's the belt that's at fault. I even tried a roller to tension the belt this morning but it was no better. I'd probably never use it at the speed where it's troublesome, but I hate it when things aren't just right.

Martin.

 

[scrimper]

I'd probably never use it at the speed where it's troublesome, but I hate it when things aren't just right.

Same as me, I just would not be happy until I got it working properly, even if it did not matter that much.

 

[boysie39]

I'd probably never use it at the speed where it's troublesome, but I hate it when things aren't just right.

Same as me, I just would not be happy until I got it working properly, even if it did not matter that much.

Now where have I heard that before I wonder . :shock: :roll: :roll:

One of the reasons I ended up with two of everything . :lol: :lol:

OH the sheer joy of it .To do it all over again .

 

[mjcann]

After much deliberation, I thought I would have a go at making the diamond nice and quiet, it was mounted on a thick lump of blockboard, but between the board and metal feet were rubber blocks, I have removed these, I made a puller next to get pulley off, to get access to counter balance, I removed that complete with quadrant, Put it all back together and bolted it down to my solid old bench, The difference is unbelievable,
Top speed and £1 coin really will stand on edge and I dont need ear defenders.
Martin

 

[martinka]

Martin, you must have a quieter motor than mine. This one shows its twin tub spin drier lineage with its sound. :mrgreen: Which balancer does yours have? Mine has the one with a long arm pivoted at the back of the saw above the motor. And which model saw is yours? Mine is the 25" and just too long to bolt to the bench. I thought about making a steel stand and making a top from pavement flags, though someone from the council might notice the holes.

T'other Martin.