Router Sled Help

[Red Lion]

Hello all,

Work has slowed down a bit here, so I have a moment to play with my festoys. I'm building a butcher block cart for my wife. The block is roughly 36" x 19" x 3" thick. The past few days have been dedicated to building a router sled jig from scrap renovation material.

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Anyhow, after I planed the block clean I noticed two things. First, the router must be tilted ever so slightly to one side, this problem is ok because I can still sand the lines out. To be honest I did excpect a fair bit of sanding after this step. Second problem I find is that it is tearing the grain in spots depending which direction the router was travelling. Is there anyway I can avoid tearing the grain in this situation? Is it a matter of going really slow? sharper router bit? Can anybody share their experiences using a router sled? Any help or insight would be very welcomed.

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Thanks for reading,

Matthew

 

[PaulMarcel]

Hi, Matthew,

Nice setup!

I can't tell which type of bit you are using, but a "bowl bit" works very well in this situation since it has a flat bottom (relatively wide) and radiused sides.  You could think of the radiused sides like the cambered corners of a plane blade helping to avoid tracks.  Here's a bowl bit from Eagle America: http://www.eagleamerica.com/product/v144-0702/ea_-_groove_forming

This type of bit can help with the tearout a bit since the leading edge of the cut is radiused so it takes it down slowly (depending on feed rate).  Another trick with endgrain is to wipe it down with mineral spirits so it is still damp when you route it.  Works great although don't soak it as it can soften uncured glue (depending on which you used).

 

[fritter63]

Is there anyway I can avoid tearing the grain in this situation? Is it a matter of going really slow? sharper router bit? Can anybody share their experiences using a router sled? Any help or insight would be very welcomed.

Try running it 90 degrees from that rather than across the strips.

Me, I'd put it through my drum sander...  [cool]

 

[Frans]

I've made me a similar jig a couple of weeks ago. I found that to prevent the tilting marks, one needs to put **no** pressure on the router at all, en be sure that the DC hose doesn't try to lift it either. Also, make only very shallow cuts.

A proper handplane should fix your block in less than a minute.

But I suspect that you will cut this block into strips and glue them together to get the endgrain on top, so you don't need to waist too much time on perfecting the surface.

Fransie

 

[Red Lion]

Thanks everybody,

I'll keep my eyes out for a bowl bit, but I'm heading out to lee valley to purchase a bottom cleaning bit:

Lee Valley Bottom Cleaning Bit

I'm keeping this cutting board as side grain - I think side grain looks better, but I understand that end grain is much better for the knives.

Thanks for the help all!

Matthew

 

[joiner1970]

These types of cutter will do the trick Im sure

http://www.wealdentool.com/acatalog/Online_Catalogue_Surface_Trim__3_Wing_250.html

 

[rmwarren]

Just for future reference I have used this bit to plane off large areas of maple face grain and it worked great, no tear-out or other issues:

CMT Bottom Cutting Bit

RMW

 

[billg71]

Nice jig, well executed but you're getting less than optimal results. Here's what I see:

Looking at photo #6 it's obvious that you're exerting uneven pressure left-to right on the push or pull strokes, every other run produces a deeper dig but it's not consistent. That means your jig is deflecting, since you(or anyone) obviously can't exactly balance pressure between directions consistently over the width of the work. Your jig needs improvement. The bowl bits others have suggested can ease the transitions but the  differences in depth of cut will still be there, you might not see them but you can feel them.

That's pretty thick Plexi/Acrylic/Lexan/whatever but you're orienting it in its' weakest direction. If you rip it to very slightly over the width of the router and glue or drill/ tap/screw the offcuts vertical to the slotted base you'll make it a lot stronger and more resistant to tipping. You'll need to be very accurate in this process, any deviation from parallel will give you less-than-straight results and waves in your table.

As far as the tearout goes, take a good look at the face grain in your photos 5 and 7. It runs every which way, horizontal, vertical and all points between, at some places you're routing end grain. If you're doing edge-grain tops and want consistent results with no tearout, you have to be pretty picky about selecting good, straight-grained wood and very careful with your orientation when gluing. Going slow and a really sharp(like brand new) bit will help but using wood like you show in your pix you'll never avoid tearout no matter how hard you try.

My advice: Forget all I've said, consider it a FYI just so you'll know what's involved. Find a nearby cabinet shop with a thickness sander big enough to accommodate your top and pay them what they want to do it. Easy-peasy, you're out a few bucks and God only knows how much time, effort and sandpaper you've saved. And you'll have a really flat parallel top to boot.

HTH,
Bill

 

[greg mann]

Nice jig, well executed but you're getting less than optimal results. Here's what I see:

As far as the tearout goes, take a good look at the face grain in your photos 5 and 7. It runs every which way, horizontal, vertical and all points between, at some places you're routing end grain. If you're doing edge-grain tops and want consistent results with no tearout, you have to be pretty picky about selecting good, straight-grained wood and very careful with your orientation when gluing. Going slow and a really sharp(like brand new) bit will help but using wood like you show in your pix you'll never avoid tearout no matter how hard you try.

HTH,
Bill

I tend to agree about the tearout except it isn't exactly every which way. Each board seems to be consistent within itself, i.e., some are tearing out on the edge to the left and some to the right, but for the most part they are consistent to each board and that probably was determined by which direction the grain ran off the side. A truly sharp cutter with a steep shearing angle will minimize this but getting the router spindle square to the face is very important too. Not only to minimize the lap marks but to also keep the bit from cutting on the trailing side, the latter condition is probably contributing to the tearout as well. I agree that the sled needs vertical stiffeners. It is best to joint the edge of the stiffeners perfectly straight and the screw through the bottom of the sled up into the stiffeners so that the flatness of the stiffeners will overcome the weep in the sled.