Diamond 19 and lateral "runout"

[AlbertoA]

Hello, I bought on ebay a Diamond 19 AFS...
It was in relatively good conditions, but some work to do of course. Primarily paint job, removing most of the old paint and rust, the nickel plating and some overal "mechanics cleaning", changin bearings, I still have to take a look at the electric part (it's all too tight in the switch box!)...
Now I am re-assembling everyting, but the upper arm is "loose". It was so when it came, but although strange I thought it might run true, but now when mounting everything it is evident that is has a bad side movement. You can see ellypses of the shiny parts moving instead of straight lines.
What do you think I can do? The "U" arms that are holding the arms are not "tight", so the arm is freely moving.
I don't know if the hole in the arms had to be 100% tight or the side to side block is something that should be done in a different way. My idea was to place a 2 0,8mm thick teflon strips between the U support and the upper arm. Any idea?
Here a re a couple of pictures of the paint work now and partially reassembled... Maybe not the original colour but a nice British Green!

So, do you think a couple of teflon plates would solve the problem? Or I would need to rework on the bores?

Thanks,
Alberto

 

[AlbertoA]

Tonight I added two pieces of Teflon on the sides of the arm, between the arm and the support and things go a little better, but know it is not the "natural" way of doing...
Did any of the Diamond owner notice the runout?
One more, the base doesn't look flat, it needs rubber feet to stay flat. Are yours the same or maybe my base is not flat (maybe the saw fell on the ground).
Thanks,
Alberto

 

[Gill]

Hi Alberto

Although I have a Diamond, I don't know very much about how they work. I hope you can get yours working in good order again.

Gill

 

[AlbertoA]

Thanks Gill.
Yesterday night I continued working on it, replaced the table and assembled everything... not even one piece was left out so that must be good :lol: !
I clamped to my jointer and switched it on... very little vibration! Even at maximum speed... I tried some test cuts and it is fantastic! I even wanted to be a little... bad and fed her with 6 cm of maple. It did not complain and made a clean cut! Of course, not as fast as cutting 1/8 plywood.
I hope that this solution will last, at worst I will need to change the teflon, I know it is not the "elegant" solution but I don't have the tools to go for that.
What makes me happy is that this lady was brought to a new life.
Alberto

 

[Gill]

Well done!

Anything that can extend the life of these lovely saws is to be commended. Mr Woodward would be proud of you.

 

[redalpha3]

Having never dismantled my Diamond it is somewhat encouraging that much of the machine seems to be user-serviceable. I think I'd be lost without it! Good luck in your efforts.

 

[AlbertoA]

Hello Pete, I worked on a few old woodworking machines that are now in my shop and I must say that all of them had pieces that you really "pray" will never break since you will never maneage to repair them unless at a high cost.
This is different. There are no "exclusive" materials, it makes you think you could build yourself one too... Well, I would not be able to, but all pieces are "commercial" pieces, some welding... but it is all quite simple.


One question, reading the "promotional material" there is a line where the "upstroke orbital movement" is claimed as something purposely done that is meant to avoid the "catching" of the piece. Do you think this is possible? Do your Diamond saws do the same?

By the way, here it is a picture of the finished work...

And here she is cutting a little maple

Thanks!
Alberto

 

[chrispuzzle]

Lovely job, Alberto - great piece of bodging with the Teflon!

As I understand it, Doug designed and built the saws with the intention that they should always be serviceable, ie, the parts can be replaced and the performance tuned for as long as you want to maintain it.

I suppose by "catching" he means the tendency of a light piece of work to be lifted by the blade on the upstroke so that it 'chatters' against the table instead of cutting. But I'm not entirely sure why a degree of slack allowing orbital movement would help with that. When I designed my little demonstration Meccano saw, although it copes with a high degree of lateral movement in the upper arm, that movement makes it more likely to chatter, as far as I can tell, not less.

Solving these problems, either by model-making or because you have a decent home workshop, is a great learning process!

 

[Gill]

There aren't many scroll saws that can cut 3 inch thick maple. It's interesting that you should say the components are commercially available. I wish some enterprising person with a bit of mechanical knowledge would resurrect this saw. When I visited Doug Woodward shortly before his death he confirmed that he bought in most of the components. There were a few parts he made himself, but not many. When Diamond was first set up it had premises capable of machining practically all the components, but his staff and partners gradually dwindled until he was left alone, making the saws by himself in a wooden workshop at the end of his garden.

What he did say was that he couldn't supply all his customers, demand was so great. There is definitely a good business opportunity here. Heck, if someone would teach me how to make the saws, I would make them myself!

 

[Gill]

My saw also has the cyclical motion on the upstroke that you describe, Alberto.

Saws like the Diamond with parallel arms have a tendency to slightly under-cut the workpiece on the up stroke. As I understand it, the Diamond is designed so that the blade pulls away slightly from the workpiece on the upstroke and any under-cut is minimised.

Of course, this is only an advantage when the blade holders face forwards. If you rotate them through 90 degrees and try to feed your workpiece in from the side, the blade action looks most peculiar :lol: .

 

[chrispuzzle]

Ah, it's the undercutting that he's trying to mitigate? Now I understand it better. Pulling away even a little would also make it easy for the sawdust to fall away from the teeth in readiness for the next stroke, I'd guess, too.

There's a rather fine looking 24" Diamond on eBay at the moment. If only I had a car!

 

[AlbertoA]

Thanks for your replies, I will try loseing the nut to see if leaving the arm a little looser would make cutting worse than it is now.
Chris yes, I meant... chatter... catch you have on a lathe... not that these are nicer since your hand can hurt a little .
Thanks Gill, now it's all more clear, maybe mine was a little too much since the blade was vibrating and you had a real big ghost. But with teflon on and loseing the nut would allow for a little more "orbit".

It would be nice if someone would follow the path... with a good project already there...
I think the problem making such a saw for an enterprising person would be time... true it is commercilly available, but it would need to be all hand made, even if in a "production" in series...
Than of course when you have it... you also need to sell it!
Beautiful that machine on ebay... cheaper than what I paid mine for (150£), and no work to do on it! Let's see where it gets though...
Alberto

 

[redalpha3]

My Diamond definitely pulls away on the upstroke. I can only echo Gill's comment that the action looks distinctly odd. I presume that it might help a little in preventing "catching" the workpiece but it certainly doesn't alleviate it completely.
I'm impressed with your restoration work. I hope your refurbished machine gives you hours of pleasure.