Parallel Rip Jig For Slider

[Jim Becker]

I recently received a PM from an SMC member regarding a parallel ripping jig that I've mentioned in the past. I probably have posted about this previously, but instead of doing a search, I'll just post the picture here as I suspect that a number of folks who have recently purchased sliders will find it useful. I use this thing a lot when preparing solid stock. Scary accurate and because the board is fast to the slider when passing the blade, the edge is "glue line"/"finish sander" ready, unlike many cuts using a rip fence. This one is pretty simple and made from scraps. There are a number of other ones that folks like Sam Blasco have made that make this one look like...well, it was made from scraps. LOL And that's a nice fresh piece of Sapele that I purchased this morning for a new tack trunk commission I picked up recently. Nice stuff.

http://img.photobucket.com/albums/v646/a-j-adopt/Woodworking/parallel-rip-jig.jpg

[Jamie Buxton]

Either I don't understand the jig, or I don't understand the name of the jig. "Parallel ripping" suggests to me that the ripped edge is parallel to something. (A standard rip fence does this. The ripped edge is parallel to the edge that was against the rip fence.) But it seems to me that there's nothing inherently parallel in this jig. You can set the board at any any angle to the line of cut. The cut will certainly be straight, but that's all. Or further if you make the initial rip to establish a straight edge, and now want to make a cut on the board that's parallel to the first cut, I don't see how the jig ensures that.

[johnny means]

How do you accurately position the stop on the jig? I bet it could do some really nice long tapers too.

Nice job and thanks for sharing.

[Jim Becker]

Either I don't understand the jig, or I don't understand the name of the jig. "Parallel ripping" suggests to me that the ripped edge is parallel to something. (A standard rip fence does this. The ripped edge is parallel to the edge that was against the rip fence.) But it seems to me that there's nothing inherently parallel in this jig. You can set the board at any any angle to the line of cut. The cut will certainly be straight, but that's all. Or further if you make the initial rip to establish a straight edge, and now want to make a cut on the board that's parallel to the first cut, I don't see how the jig ensures that.

Jamie, the jig is used in conjunction with the stops on the miter fence shown at the end of the slider wagon. Once you have a straight edge on the board, you flip it around so it butts up to the stop on the miter fence and is also in contact with the jig...which is aligned exactly the same distance from the blade as the stop on the miter fence. With my simple jig, I measure the first piece and literally use the (stopped) blade to line up that end of the cut while tightening down the jig's stop. More sophisticated versions have an accurate measurement, just like the miter fence stops...set the distance on both to the same and cut away. So with all that said, "parallel ripping" is indeed the case...each cut is parallel to the existing straight edge if both stops are set correctly. Now this might seem like a bit of work, but I assure you that the end result truly is better than using the ripping fence because the wood is held down to the wagon and moved through the cut in a very, very stable way. No matter how good you are when working with a standard ripping fence, there will be slight variation in movements including both feed speed and slight changes in contact pressure to the fence. And the fence is almost never be exactly parallel to the blade to insure there is no binding. I only use my rip fence for very narrow rips because in that case it's safer...a very narrow piece can't be held safely on the wagon.


How do you accurately position the stop on the jig? I bet it could do some really nice long tapers too.



Yes, in theory one could use it in that manner, especially for very slight tapers. More angle would really require you to change to a small stop at the miter fence so the board isn't interfered with at an angle and the stop on the jig would best be changed to a "point stop" for the same reason. I have another jig I use for tapers...it's similar to those that many folks use with a regular rip fence, except it's designed to be secured to the slider wagon. Again, the cut edge tends to be better because the workpiece is absolutely held secure while it's moved through the cut at a very constant speed end-to-end. That's hard to do when running a jig against a fence manually.

Please note I'm not saying that using a regular rip fence is in any way bad or inadequate...I'm just stating that I find that being able to lock things down on the slider wagon makes for an even better cut.

[Jamie Buxton]

... the jig is used in conjunction with the stops on the miter fence shown at the end of the slider wagon. Once you have a straight edge on the board, you flip it around so it butts up to the stop on the miter fence and is also in contact with the jig...which is aligned exactly the same distance from the blade as the stop on the miter fence. With my simple jig, I measure the first piece and literally use the (stopped) blade to line up that end of the cut while tightening down the jig's stop. ... .

So you're setting a stop on the miter fence, and then separately measuring to set the stop at the feed end? And if you don't set the two stops to be the same, you get a tapered rip? That sounds like the old days of rip fences which wouldn't stay parallel to the blade. We'd measure at the front of the blade, then the rear of the blade, and adjust until they were the same. Modern rip fences were a revelation because they'd just be parallel without effort.

[Jim Becker]

Jamie, that's an absolutely true statement. With a more sophisticated jig that has an accurate scale, this is a quick and easy...and accurate, outside of human failure...method. With my quick and dirty jig, I have to measure. But you know what...it's actually been good for me because it means I tend to check things twice automatically before cutting and keep a more sane pace while working. I make far less mistakes as a result.

This is obviously a trade-off. The rip fence offers quick set of the width and cut with little muss and fuss. The parallel jig on the slider takes more time, but it offers the ability to have a workpiece locked down as it moves through the cut for both a better cut surface and no hands coming near the blade. I've chosen the latter as my primary method for two reasons. One being the quality and safety that I've already mentioned. The other is that I pretty much never edge joint anymore. My J/P gets used in jointer mode for flattening boards and everything else is just thicknessing. I never return to the jointer after making a cut on the saw...no need to.

[Chris Fournier]

I have to agree with Jamie on this one. While I do really like shop made set ups that help me work faster or get a better product I see this set up as not really doing either - for the way I work at least.

I have ripped the second parallel edge running off the the rip fence for many years and continue to do so on my panel saw with results that are ready for glue up. I make sure to keep the offcut on the left side of the blade no wider than the cast iron table or not on the slider otherwise the board is elevated by the silder on the offcut side - not good.

I do appreciate the fact that the slider table allows a sweet feedrate control but it does also hold the stock above the right side of the blade which I have found can have negative effects on the cut quality if the board is not very flat and very well secured to the slider table. You win one but lose another I find.

Your jig could be made much more simply and require NO measuring (with the exception of setting the desired width at the mitre fence) or moving parts by simply cutting some perfectly square panels. Once you have a square panel break out the X and Y ratios that you want with a rip or diagonal cut and you now have some large squares to guide your second ripping operation on the slider. Reference the Y axis on the mitre gauge and the X axis guides the board - done. Make a couple of different sizes for shorter and longer boards and you are done. Simple to make, use and store.

[David Kumm]

Parallel ripping is especially nice if your slider has pneumatic clamps on them. I use them and really great for thin strips and anytime you don't want hands around the saw. Dave

[Eric McCune]

Jim, thanks for posting. Since I'm new to sliders this discussion has really helped me.

Chris, shouldn't your cast iron table and slider be flat? I'm surprised the slider would elevate the work. Wouldn't this be an issue with sheet goods? Maybe I'm not understanding. Thanks.

[David Kumm]

Eric, A slider rides proud of the table. How much is up to you. For a saw shaper it usually is adjusted only a few thousands above. Not a big issue. I use both types of saws for ripping and find both work better than the other in certain applications. Traditional ripping on a slide is more difficult due to the slider sticking out in front and once the crosscut fence is set, it is a pain to take off so ripping using the slider saves time. Having both saves the most time. Each supports a different way of ripping but you have to get comfortable with euro saws. Repetitive rips with the fence adjusted forward and using the slider is really useful as well. Dave

[Chris Fournier]

No Eric, the slider table is always elevated over the height of the cast table, this is the factory set up and it reduces the friction forces of dragging a large piece of work over the cast table while using the slider. The SCM slider is set about .010" to .015" over the cast table height.

[Peter Quinn]

... but I assure you that the end result truly is better than using the ripping fence because the wood is held down to the wagon and moved through the cut in a very, very stable way. No matter how good you are when working with a standard ripping fence, there will be slight variation in movements including both feed speed and slight changes in contact pressure to the fence. And the fence is almost never be exactly parallel to the blade to insure there is no binding.

I like the jig Jim, and I have used something similar at work, bot ONLY for the purpose of making long slender tapers, such as for a segmented radius flooring inlay or to straight line an occasional slab of something. The statement about traditional cabinet saw ripping has IMO some flaws. I like the theory you present, very similar to how metal passes across a bridgeport mill, the "deadwood" concept"? Secure the work and move the table for accuracy. However, slider or not, many ripping operations release tension in solid wood, and this tension pushing on the blade causes some inaccuracies, and the slider does nothing to alleviate this condition versus a traditional approach. I have experienced burnt edges as a result of release of tension even when using a slider and it is no less of a problem then on a cabinet saw, though there is no real kick back danger. If the saw blades plate is 1/8", the wood can and will push it around.

While the sliding carriage may make a consistent feed rate more approachable, as long as a human is pushing the carriage, consistency of feed is only as good as the operator, no guarantee there. For very consistent feed rate a power feed is necessary. I often use a power feed on the bridgeport table, I know of no way to add that feature to a sliding saw carriage. It is quite easy to put a power feed on a cabinet saw, I do it regularly and the results are quite hard to beat. But in reality even a basic feather board and mechanical hold down scheme that keeps the wood on the fence and allows the user to focus on feed rate will yield consistent results. So I guess I'm saying that an experienced TS user can develop a very accurate hand feed technique that rivals the results of a slider user, but changing rip widths is quite a bit more expeditious on a cabinet saw.

On the statement of "rip fences are rarely parallel", did you really mean that? There is no guarantee that a slider, with all those adjustments, fences, the carriage, the miter bar, the parallel bar, is anything close to parallel or accurate. That is the clearly the job of the operator to set up accurately. I find that a t-square type ripping fence with so few moving parts and such a simple design is probably the easiest thing to set up in my shop, and having had to set up several sliders it is not a job I look forward to. The one consolation is that they generally hold those settings quite well so maintenance is not often required, but I can say the same for the t square rip fence.

[Eric McCune]

David and Chris, thanks for your replies. I guess I need to measure the gap on mine.

[Jim Becker]

On the statement of "rip fences are rarely parallel", did you really mean that?

The context of that statement is that most folks have the outfeed side of the fence angled slightly away from the back of the blade...not much, but a little...and that gives a little wiggle room.
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Folks, the conversation is interesting. For me, this method works well and helps me pace things, too. It's obviously not for everyone. One thing I didn't mention is that I also like this method because with a heavy sliding table saw, there is more saw in the way of your body when you are using the traditional rip fence. I don't always find that comfortable and using the jig eliminates that for me. Again...it's great that we all have so many choices!

[Tommy Squires]

Jim, thank you for your post. Reading your experience with the MM slider is one reason I own one today and I am very grateful that I do. I too lusted after Sam's version but could never quite pull the trigger on an expensive arm like his. I tried a very crude version of what you have with limited success. I don't keep my miter fence mounted on my slider. Do you use this jig of yours in conjuction with your large panel fence as well?

[Jim Becker]

Tommy, I don't use it with the large panel fence...which I only have on the saw when I'm actually cutting up sheet goods. My shop just isn't big enough to keep that thing on the machine and even when I'm using it, I have to carefully plan my own body's position for each cut when full sheets are on the thing! That's because of where my J/P has to live. I'm actually considering cutting down the table on the back of the saw to move it farther away from my J/P. I don't use it for anything most of the time, anyway, and could stand to lose a foot off of it without even noticing. Of course, I'd have to rent a pallet truck to move the saw back then...1500 lbs is too much to just "push" :o

I finally got to see Sam's inventions up close and personal in April when I was in the Austin area on business and got together with him and his family for dinner. I can only say "wow"...Sam is not only an exquisite craftsman and great person in general, but also a very gifted "engineer" when it comes to jigs and machinery attachments. Here's a picture from my visit next to one of his two "really big" bandsaws.

http://img.photobucket.com/albums/v646/a-j-adopt/sam.jpg

[Tommy Squires]

Thanks Jim. I find myself using the large panel fence for most everything. Your jig should work for either fence. I have copied your photo and added to my list of project to build.

Wow, I don't think I would have recognized Sam. When I last saw him his hair was closer in length to yours (and mine) and his son.....he was asleep in an infant carrier. My time flies when you're have this much fun.

Sam talked me into a 24" MM bandsaw when I was setting up my shop. Really had to twist my arm! I love it. Use it almost every day. I am lusting after that sander you are leaning on. So many tools, so little time.

[Jim Becker]

Sam does theater, too, and the production he was in at the time (something he participated in writing) required that "look"...the kewel thing is that the theater is just a few doors down from his studio. That little town he lives in is really great and frequently used in big-screen films, too.

Yes, the jig will work with either the miter fence or the panel fence. I wish I had the space to keep the panel fence on more, but I just don't. It would also get in the way of my router setup which makes my saw mimic a saw/shaper configuration using a BenchDog cast iron top. (there's a thread here for that... :) )