Hi John:

?

You make good points about both the use of a bandsaw and thicknessing on edge. And with regard to the slightly ‘out of square’ issue. It is very minor like you say, but enough to notice. When it matters (e.g. for gluing up, joinery work, kumiko, etc.) I will always make two rip cuts. The first cut is slightly wide, and the second cut for that perfect rip where the material does not ride up on the slider.

?

(Yes, yes, I know this is hard on the blade and is probably a bad habit. But it works for me.)

?

There is another technique that I’m not sure has been mentioned much on FOG. I sometimes parallel rip on the slider without a parallel fence by measuring the overhang of material. Here are the steps:

?

1. Take any material, clamp it down to the sliding table, and cut it with the blade intended for ripping (e.g. 3.2/2.2 x 30mm).

?

2. Do not unclamp the material. Now take a steel ruler or callipers and carefully measure the overhang of material in relation to the right edge of the sliding table. For my saw, Kappa 400, the overhang is exactly 5.5mm. This is the distance between the right side of the sliding extrusion, and the left edge of my 3.2/2.2mm blade.

?

3. Armed with the offset of 5.5mm (or whatever yours is), and with the slider retracted, place the first edge of whatever you’re trying to dimension on the slider and position it so it overhangs by roughly 5-6mm off the right edge of the sliding table.

?

4. Clamp the board in place and use an accurate steel ruler or callipers to measure the offset. If it is less than 5.5mm, then the blade will not cut. If it is 6mm, then the blade will remove 0.5mm of material. You get the idea (hopefully).

?

5. Both ends of the board must be checked to ensure it overhangs by more than 5.5mm. Adjust as needed and reclamp. Make the cut.

?

6. If you’re planning on a trim cut only (i.e. not taking off much), make sure to account for any bow in the material. If the bow is outwards or convex, then the blade will engage at either measured end, and simply take more stock out of the middle (where the bow is largest). But if the bow is inwards or concave, you need to make sure the entire length of material is overhanging the slider by more than 5.5mm.

?

7. I do this procedure where I don’t have a lot of width to work with and I want to trim the minimum amount to achieve a straight line rip. If there is plenty of width, I just eye-ball it. I guess some of us (not me) have a laser and just use that.

?

8. If the stock is not too long (e.g. less than 1200mm) I simply set the rip fence and parallel rip in the conventional way. I’m assuming a small sample size here. It is far less tiring and safer to take the time to set up proper parallel fence/s for repetitive rips for larger jobs.

?

9. If the stock is long, say 2-3m, but I only need to rip one, I’ll do some mental arithmetic and do a parallel rip on the basis of the overhang amount. I can get very close using this method (at least down to 0.2mm). If the board has to be exactly parallel, I always break out Brian’s parallel fence, calibrate it using my magnetic ‘calibration device’ so that it agrees exactly with my cross-cut fence stop. And parallel rip that way.

?

Again, I hope this helps.

?

?

Ahem, I rip on the right side of the blade all the time on my Kappa 400.

?

Yes, we consistently get a better finish (cleaner cut, more consistent, straight) when using the sliding table and a mixture of clamps and jigs. However, that mixture of clamps and jigs takes time to get exactly right. Not a lot of time, but enough time for resentment to build.

?

So here are rules of thumb I use:

?

• If I need to rip 1-5 items that are not any longer than say 1200mm, I don’t even think about it. I go straight to the right side of the blade for a conventional rip.

?

• If the outcome is critical, and I’m relying on as perfect-as-possible-result, I usually take the time to work on the left side of the blade, using the slider.

?

• I say ‘usually’ because short stock, say 600mm or shorter, can be ripped on the right side of the blade with perfection. I have done so literally thousands of times so my sample size is adequate.

?

Keys to ripping ‘perfectly’ on the right side of the blade.

?

• Rip fence toe out must be dialled in. I defer to da Best (a.k.a. David Best) for details if you need help on this.

?

• The material to be ripped must have one straight edge, and must be flat. Cup, bow and twist will have a very negative impact on ripping (on either side of the blade), especially when the material is hand-fed through the blade.

?

• The riving knife and blade selection is important. These must be correctly calibrated and chosen.

?

• Feed-rate is important. There is definitely ‘too slow’ but most videos online show a feed-rate that is too fast to way-to-fast. Experimenting with your saw and blade combination is key. Make four sample rip cuts at different feed rates and inspect the results. As the feed-rate is reduced, the surface quality of the rip will increase, but only to a point. Going any slower just dulls the blade.

?

• Consistency is important. Many operators do not concentrate on the feed-rate for the entirely of the cut. The introduction to the blade, passing through the cut, and exiting the material from the back of the blade, are all of equal importance. I see operators ‘finish a cut’ and then quickly exit the back of the blade. This results in a slight roughness to the edge. Exactly the same feed-rate – like a power feeder – is required throughout.

?

• Focus on hand positioning so that there are absolutely no transitional issues from using a hand
• or push stick. In fact, if you feel you need a push stick due to the width of the material being ripped, you must (in my opinion) move to the left side of the blade, because the transition from fingers to a push stick nearly always results in a less-than-perfect ripping result. I can rip 1200mm length stock with no transition whatsoever, and use my thumb for the entire cut. You can work out your own maximum length for perfection.

?

• I don’t buy the argument about how much harder it is to rip (on the right side) using a slider. It is not a jot harder; it is just different. Unless you have unusually short arms, it is entirely possible to keep your head to the left side of the blade, while using your right arm and hand to push material on the right side of the blade. I’m willing to post a video on request but this stuff is pretty self-explanatory.

?

• For all of this, I’m assuming you have a ‘good’ blade guard fitted to your slider. No ‘good’ blade guard and all of my words are essentially worthless. In my opinion, you should never present any part of your body, hand, arm, head, whatever, in front of the blade without a ‘good’ guard.

?

• And finally, and probably most controversially, I’m happy to rip material much narrower than recommended because of the stout nature of the Felder overhead guard. The Kappa 400 guard is stout enough that I can push sideways with very considerable strength, and the guard will not move enough to touch a running blade. Consequently, with the rip fence in the low position, if I can get a good grip on the material, I have no problem allowing my hand, thumb and fingers to ride against the right side of the blade guard as it passes by. If adjusted low (i.e. a few mm above the stock) the risk is exceptionally low, in my opinion. But that is just me. You find your own width and own your own decisions. I explicitly take no responsibility here in expressing my methods of work.

?

I hope this is helpful.

J’espère que cela est utile!

(Mais, Dumas est trop difficile pour moi!)

?

?

Hi Bryce:

?

Thanks for your post. With regard to the heat, I wonder whether you have been running it without ducting, or without much ducting while you sort out the niggles? If so, the RL machines (and most extractors I imagine) are not designed to run very long without ducting. The RLs will definitely overheat, as they need the ‘back pressure’ (if that is the correct description) of reasonable amounts of ducting (several metres), otherwise the motor and impeller will work at above max-amps (with associated over heating).

?

My RL160 did not get hot at all. My RL250 does not get hot at all. Sure, the motor must warm up considerably on extended use, but it must be over-hot if you can feel heat-transfer to the sheet-metal surrounding, or if the air exhaust is noticeably hot. In such cases, I would be wanting to assess motor issues going forward.

?

?