Shopsmith Forums

Read this post before reading any of this thread!!!!
http://www.shopsmith.com/ss_forum/viewt ... 21#p209321


A few days past, a mention was made of the short rip fences used by folks in the United Kingdom.(aka Brits...)

It described using a fence adjusted so the back end is no further than the root of the saw blade gullet.

The purpose is the elimination of kick back.

Being of a curious nature, I decided to try and make a jig to do the same on my Goldie Mark 5(aka 500).

Since the blade height setting alters the 'gullet root' position, the end of the fence needed to be adjustable .

So here is a side view showing the slots that allow that adjustment.
The 'end' is not vertical so as to reduce the amount of adjustment needed between thin and thicker workpieces. The 'end' is actually a 1/4" inset away from the blade.

There are three through holes in the SS Mark 5 rip fence. Two are used for the sliding 'short fence'. The third provides support at the far end for ripping long boards
(more about it later).


The 'short fence' is positioned so that the workpiece is cut through just immediately prior to the inset causing the workpiece to slip away from the blade.
This pix illustrates setup only and does not show actual cutting.

The last pix shows the motion the workpiece takes as it enters the inset.
Notice the trailing end moves away from the blade, but the back end does also. That is what reduces kickback. Again the pix does not actually show ripping happening.

Now about that rear spacer. It must be beyond the rear of the blade or we would have the same situation as a continuous fence.(kickback) By being behind the back of the blade allows the workpiece to move away from the blade as the trailing end slips into the inset.


Now the CAVEATS.

I do NOT recommend this, but am posting it as an experiment.

I do not see how this would work with a push stick.

Technique required is different.

Pressure pushing the very end of the trailing end towards the fence MUST be maintained(much more so than with the OEM fence).

Also the cut off needs to be controlled.






Yes that first pix is also a sneak preview of the Mark VII base.

Interesting experiment!

Is the rear spacer the same thickness as the infeed fence? If so, it would seem to create hazards of its own. If not, what good is it?

Do you believe this style of fence offers any advantages at all?

Is your blade really as dull as it looks?

BuckeyeDennis wrote:Interesting experiment!

Is the rear spacer the same thickness as the infeed fence? If so, it would seem to create hazards of its own. If not, what good is it?

Do you believe this style of fence offers any advantages at all?

Is your blade really as dull as it looks?

The rear spacer = full fence width. Any hazard(other than providing a possible hang point) is no more than a full fence.

Time will tell re any advantage(s). It will require getting used to.

That blade is quite functional albeit needs a bath. What do you expect from an e-bay purchase come along for the ride blade.

Having invested a bit of time in this, I will be trying it out, but do not have much hope for it being either a permanent feature nor replaced with a better attempt(one piece) from better material.

What ever you do, just be careful in your experiments .... We need you around for a while yet!

rjent wrote:What ever you do, just be careful in your experiments .... We need you around for a while yet!

Whatcha got in mind?

Fear Not - I may be prone to risky behavior, but not fool hardy.

I do not believe accidents just happen. They are caused. Usually by an operator.

JPG wrote:

BuckeyeDennis wrote:Interesting experiment!

Is the rear spacer the same thickness as the infeed fence? If so, it would seem to create hazards of its own. If not, what good is it?

Do you believe this style of fence offers any advantages at all?

Is your blade really as dull as it looks?

The rear spacer = full fence width. Any hazard(other than providing a possible hang point) is no more than a full fence.

Time will tell re any advantage(s). It will require getting used to.

That blade is quite functional albeit needs a bath. What do you expect from an e-bay purchase come along for the ride blade.

Having invested a bit of time in this, I will be trying it out, but do not have much hope for it being either a permanent feature nor replaced with a better attempt(one piece) from better material.

Here's what I was thinking about that rear spacer. If full fence width, it creates a hang point, as you mention. So I would be tempted to bevel the infeed edge of it to avoid hangups. But should that bevel actually be encountered by the workpiece, it would shove the workpiece, rather quickly, sideways toward the rear of the blade. Which would seem to be more dangerous than a conventional unbroken fence.

BuckeyeDennis wrote:

JPG wrote:

BuckeyeDennis wrote:Interesting experiment!

Is the rear spacer the same thickness as the infeed fence? If so, it would seem to create hazards of its own. If not, what good is it?

Do you believe this style of fence offers any advantages at all?

Is your blade really as dull as it looks?

The rear spacer = full fence width. Any hazard(other than providing a possible hang point) is no more than a full fence.

Time will tell re any advantage(s). It will require getting used to.

That blade is quite functional albeit needs a bath. What do you expect from an e-bay purchase come along for the ride blade.

Having invested a bit of time in this, I will be trying it out, but do not have much hope for it being either a permanent feature nor replaced with a better attempt(one piece) from better material.

Here's what I was thinking about that rear spacer. If full fence width, it creates a hang point, as you mention. So I would be tempted to bevel the infeed edge of it to avoid hangups. But should that bevel actually be encountered by the workpiece, it would shove the workpiece, rather quickly, sideways toward the rear of the blade. Which would seem to be more dangerous than a conventional unbroken fence.

Bevel, yes.

However consider that any hangup is the result of warpage. That same warpage will push it against the blade over a greater distance with the 'unbroken fence'. I agree that sudden contact due to the bevel could be 'bothersome'(a medical term ). However, due to that warpage, the kerf is wider and the sudden contact point may be away from the teeth(closer to the center). Also that warpage will likely cause the 'cutoff' to be riding the other side of the teeth(regardless of fence continuity).

Keep in mind this originated from across the pond. After all they do not drive on the right side of the road over there.

I'm guessing you are modeling this off something, at least as a reference, would you mind sharing that with us?

I personally have no knowledge of British saw technology other then what I have seen on wood working tv shows. This is pretty limited I have to admit. I also believe it was Delta that offered a short fence, maybe still do? One of the woodworking guys had one at least for a while.

So from what I have seen, again it has been limited, the fence is short and ends with no secondary area beyond the blade. Second they always have a riving knife.

So far in your design I see no riving knife so there is no provision to keep the wood from contacting the blade on the back side. Since you plan to test this are you planning to provide such a device and if not why not?

Ed

Be careful JPG. I agree with Ed. That design appears to be an accident waiting to happen. Is this a standard thing across the pond or something someone has used on a limited basis ?
Paul

https://youtu.be/d7QXIN2X8-w

Safe ripping with a short fence. Interesting.