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Forum topic by mcnerd posted 12-16-2016 03:01 PM 2712 views 0 times favorited 10 replies Add to Favorites Watch
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mcnerd

4 posts in 610 days


12-16-2016 03:01 PM

I have a question regarding safety on a crosscut sled. I have googled this to death and can not seem to draw a clear conclusion.

First, I am hobby woodworker, but quite a few years of experience and my fair share of kickbacks.

My root question is this…

When using a cross cut sled with a stop block that does not “flip” out of the way for when you cut does this not create a “trapped” piece situation?

I am planning my second cross cut sled build and wanted to incorporate a stop block. I see lots of pictures and plans for sleds that have stop blocks incorporated into them that would in fact create the “trapped” issue.

Here is one example of a design with a stop block for reference:

or…

Is this only an issue on a very small parts where vibration would send cut piece moving around?

Thanks in advance.


10 replies so far

View Beaver_Lumber's profile

Beaver_Lumber

6 posts in 2381 days


#1 posted 12-16-2016 03:15 PM

mcnerd,

you won’t have the “trapped offcut” issue with a crosscut sled because once loose from the work piece, the offcut is still being pushed forward by the sled’s fence and the stop block does not push the offcut against the blade. Also, there is still some space for the offcut to escape toward the right side. The surface of the stop block contacting the work piece is so tiny that it won’t cause problems…

-- Patrick - A beaver is like a woodworker because it needs to have wood between its paws

View Redoak49's profile

Redoak49

3397 posts in 2071 days


#2 posted 12-16-2016 03:36 PM

I have a sled with a very similar set up with no problems.

I do have a concern with your comment of having your fair share of kick backs. IMHO when you have one you need to stop and carefully consider what happened. If you have had multiple kick backs, you need to change the way you are doing things. I have not had one in years.

View HokieKen's profile

HokieKen

5838 posts in 1221 days


#3 posted 12-16-2016 03:43 PM

I have fixed stop blocks on my sled and have never had any issues.

Another way to tackle it if you’re worried about it, is to use a thin shim between the stop block and the workpiece. Once you have it set, remove the spacer before making the cut.

-- Kenny, SW VA, Go Hokies!!!

View mcnerd's profile

mcnerd

4 posts in 610 days


#4 posted 12-16-2016 03:59 PM


I have a sled with a very similar set up with no problems.

I do have a concern with your comment of having your fair share of kick backs. IMHO when you have one you need to stop and carefully consider what happened. If you have had multiple kick backs, you need to change the way you are doing things. I have not had one in years.

- Redoak49

Your point is valid but to add context to why I mentioned it.

Your exactly right, early on I was NOT properly trained on how a table saw worked. Then I had a kickback and a WTH moment. Life flashes before your eyes. At that moment in time I turned my attention to understanding the physics of this powerful tool. The table saw I use today is the same one I bought in 2002. As I get older I continue to invest in things that make it safer, Grippper’s for example.

And to be clear… I think it is three kickbacks in about 15 years. They are all very vivid memories. :)

But more importantly I come to places like LumberJocks and ask questions and read to LEARN.

Now soap box.

Kind of the point of asking the original question eh?

So my own comment back, I would not be too critical of someone about safety as they are ASKING a question about SAFETY. And one of the MAJOR benefits of forums like this is the open shared knowledge, others can find the information and learn at a faster pace…in this case learning to be more SAFE. I am thick skinned enough to handle it, others may not be. I would hate for someone to be deterred from asking a question of fear of being made to feel dumb by those they are seeking knowledge from.

Soap box over.

View hotbyte's profile

hotbyte

991 posts in 3058 days


#5 posted 12-16-2016 04:04 PM

I would think, as mentioned above, the continued support from the sled’s rear fence will prevent/reduce chance of kick-back. When creating a trapped piece between blade and rip fence with a mite gauge, there is no support behind the piece once cut through so it can rotate slightly, wedge between blade & rip fence causing the piece to take off like a rocket ship.

On a sled, it should be similar to the “keeper” end when using a miter gauge with a stop block…

View mcnerd's profile

mcnerd

4 posts in 610 days


#6 posted 12-16-2016 04:08 PM



mcnerd,

you won t have the “trapped offcut” issue with a crosscut sled because once loose from the work piece, the offcut is still being pushed forward by the sled s fence and the stop block does not push the offcut against the blade. Also, there is still some space for the offcut to escape toward the right side. The surface of the stop block contacting the work piece is so tiny that it won t cause problems…

- Beaver_Lumber

Mentally this is where I was at with it. Hold downs for certain size items relieve this problem as well in certain cases as well as remove your hand from proximity to the blade.

So leads to my other point of concern….the small pieces which are free to move around down there. Using a shim for example that is removed to give it more room is an option.

Thanks for the comments.

View mcnerd's profile

mcnerd

4 posts in 610 days


#7 posted 12-16-2016 04:30 PM



I would think, as mentioned above, the continued support from the sled s rear fence will prevent/reduce chance of kick-back. When creating a trapped piece between blade and rip fence with a mite gauge, there is no support behind the piece once cut through so it can rotate slightly, wedge between blade & rip fence causing the piece to take off like a rocket ship.

On a sled, it should be similar to the “keeper” end when using a miter gauge with a stop block…

- hotbyte

Great point I had not considered. The support of the piece by the sled keeps it from pivoting. if you are holding with your hand this helps even more and best yet a hold down of sorts.

I already understood this logic had just not applied it yet. The reason using a rip fence as a guide with a cross cut is so dangerous is because on a longer board it is so easy to pivot as the forces are multiplied. where as on a rip this phenomenon is almost eliminated until you get to sheet goods.

View Rick  Dennington's profile

Rick Dennington

6009 posts in 3277 days


#8 posted 12-16-2016 04:32 PM

One of the best solutions, if you’re worried about the piece being “trapped”, is to use a “flip up” stop block. You can make one using a common cabinet hinge, and 2 small blocks attached to the hinge, and mounted to a T trak with a toilet bolt and nut….or buy one like the Kreg Flip-Up stop, using the same method….If you want to see how the home made stop with the hinge is made, go to Young Je’s Youtube and watch him build a crosscut sled….

-- " It's a rat race out there, and the rats are winning....!!"

View Logan Windram's profile

Logan Windram

346 posts in 2545 days


#9 posted 12-16-2016 05:47 PM



I have a question regarding safety on a crosscut sled. I have googled this to death and can not seem to draw a clear conclusion.

First, I am hobby woodworker, but quite a few years of experience and my fair share of kickbacks.

My root question is this…

When using a cross cut sled with a stop block that does not “flip” out of the way for when you cut does this not create a “trapped” piece situation?

I am planning my second cross cut sled build and wanted to incorporate a stop block. I see lots of pictures and plans for sleds that have stop blocks incorporated into them that would in fact create the “trapped” issue.

Here is one example of a design with a stop block for reference:

or…

Is this only an issue on a very small parts where vibration would send cut piece moving around?

Thanks in advance.

- mcnerd

Is you intended piece the small one that will be between the stop block and the blade, or the long piece in that picture? If its the long piece, the stop block should be on the other side of that cut, and the little cut off should cut off a simple lay to the right of the blade harmlessly.

If you’re trying to cut a bunch of small pieces, a sled isn’t the best choice unless you are using a spacer each time you laod up your next cut or have a flip-up stop block.

View clin's profile

clin

911 posts in 1079 days


#10 posted 12-16-2016 05:55 PM

Another vote for it’s okay. And here’s my version of why.

When using a miter gauge and the fence as a stop, the miter gauge of course has to stop short of the blade. Therefore the off cut is completely unsupported between the blade and fence. Blade is mostly spinning forward, though down at the front and up at the back.

No support on the wood, and a blade that is pushing on the off cut at one end. So wood is being twisted and wedging between blade and fence. In other words, what many others have said.

With a stop block and fence that supports the cut all the way through the cut, there’s no twisting force on the piece. While the blade is still pushing the end of the piece back, the fence is supporting the piece right at that same spot. So the forces cancel and are not creating a rotational moment.

Another thing I’ve not seen mentioned is that fact that the piece is also riding on a sled. From the work piece’s perspective, the ONLY thing moving is the saw blade.

Having said all that, I do think there is still some potential for a problem because in the end, you have a small piece of wood fractions of an inch from a fast moving blade. Though I don’t think this has as much to do with a stop block as simply having an unsupported off-cut. But still, much more support when using a sled.

-- Clin

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