Thread: Novice using Douglas Shaper

Don't forget the oil. No really. Pay careful attention to lubrication, especially the ram and main bearings. Make sure it's getting where it needs to go. Be generous.

Although I have no shaper experience yet I'll say 2 things. If you leadscrew is 8 tpi then one turn gives you 125 thou advance, so divide 125 by the number of graduations and you have your feed per mark. Also, you shouldn't have something in only one side of the vice, the vice jaws will skew. You either need to use the middle or have something equal on the other side.
Ewan

Hi Ben
No more than 1/4' past the work and 1/2" before the work for stroke. Too much speed before the tool hits the work causes the tool to bounce effecting surface finish. Check the direction of rotation too. The sliding block should be at the top of the yolk on the cutting stroke.

Phil

ps I am with Bryan. Heaps of oil in the right spots. Like mine you have plain bearings.

What did you mean when you talk about too much speed before the tool hits the work?

Hi pipeclay
If the tool goes too far past the end of the work, the ram, because of the position of the sliding block in the yolk, and the moments of leverage, accelerates on the return stroke. When the tool hits the work the extra speed bounces the tool when it hits leaving a noticeable mark on the surface finish.

Phil

That didnt come across as meaning that in the way it was 1st written,it tended from my understanding that the tool was in the forward direction.

Ok, Now i'm confused, i thought Phil was talking about the start of the cut, ie you want the cutter to start at a slower rate and accelerate as it is cutting. Actually, thinking about it, do you mean the tool hitting the job on the return stroke and jumping up and coming down on the job? I've got to pay attention to these things now.....

Ewan

Pipeclay,
At the start and end of the stroke, the tool accelerates and decelerates. It is fastest in the centre of the stroke - at the top and bottom dead centers of the bull wheel crank pin positions.
So if the tool changes direction close to the work, it hits the work at a slow speed and accelerates while cutting. At the other end, that is possibly not that important but wastes time.
By the way, I found the "bounce" cutting a real problem with an interrupted cut I tried (a 1" gap in my work piece). Sounds awful too when the tool hits the second section at full tilt....
Joe

Thanks Joe, well explained (clearly something I am not good at)
Pipeclay, the tool hits the job on the return stroke as well. Thats why they put on a clapperbox. That way it can swing out the way, on the return stroke. On the forward stroke, tool bounce will happen but to a much lesser degree.
Try this. Put a piece of stock in the lathe and feed the tool into it (longitudinally) by hand as fast as you can. Then move the tool up to it slowly, start the cut, then accelerate the feed.
Which way would you prefer to do it? Now I know they are different forms of machining but the mechanics of metal removal are the same.
I will apologise in advance for this crappy explanation

Phil

I think the only times I have experienced any tool bounce on a forward stroke is when I have been pushing the machine to its limit in depth of cut,which I would put into the same category as chatter you would find with a lathe.
As far as speed of stroke altering through the cutting cycle start/end thats fine,much easier to see this on a planer.
Just hope that comment dosent cause opperators new to a shaper to overly complicate there tool setting stroke setting,they will virtually be worrying over nothing.

Originally Posted by pipeclay

I think the only times I have experienced any tool bounce on a forward stroke is when I have been pushing the machine to its limit in depth of cut,which I would put into the same category as chatter you would find with a lathe.
As far as speed of stroke altering through the cutting cycle start/end thats fine,much easier to see this on a planer.
Just hope that comment dosent cause opperators new to a shaper to overly complicate there tool setting stroke setting,they will virtually be worrying over nothing.

Hi Pipeclay,
I disagree, chatter is different to tool bounce. I also don't agree with simplifying something that isn't complicated. At some point the ram position and stroke length has to be set. Why not do it right in the first place. I am sure the readers of this forum would rather know the correct procedure rather than one I think is less complicated. I actually find that condescending and a sleight on their intelligence. I have never 'dumbed down' for an apprentice and I don't intend to start now.
I also have no intention of apologising in advance for my little rant.

Phil

There is I feel a very big difference between instructing an apprentice and trying to share knowledge on a forum.
If it was a trade based reference forum I think that would be fine.
From what I have read numerous times in this section of the forum it would appear that a good portion of the users are self taught,either through trial and error or books.
A good proportion of the questions asked by people get a very detailed answer,this I have noticed sometimes complicates there outcome.
It is very hard to try and explain things in a basic way that someone without a trade background can understand clearly.

Originally Posted by pipeclay

It is very hard to try and explain things in a basic way that someone without a trade background can understand clearly.

What, like an apprentice. I am yet to meet an apprentice with a trade background already under their belt.
But, if you insist...

Phil

And your point was.