[hagheid]

Just been using a 1/4" 12.7mm straight bit on my Elu midget Router table to cut a slot crossgrain on a piece of 6" x 12.5mm soft pine. The job is to produce a 'slide' that fits the slots on either side & will accommodate a 'sliding' base or tray cut from the same size of stock.
Basically it's a box that has a tray on the bottom that can be removed. Trouble is that for one reason (or MANY) I'm getting a fairly rough cut which without expecting 'perfection' I'd like to improve.
Remedies I'm planning are New Trend Straight bit cutter, Increase/Decrease speed of Router? or Use Hardwood! (only joking!)
Is it possible to effect a clean(ish) cut on this cheap & cheerful Timber with less tearout?

 

[hagheid]

Couple of photos of the vandalised wood!

 

[Job and Knock]

There's pine, and the there's pine. A lot of the stuff sold by the likes of B&Q (for American readers this is our equivalent of "the Borg" or Home Depot) is white pine - really meant only for wall studwork and rough carpentry and just not of joinery quality. What you need to use is joinery quality redwood (not the same as redwood in the USA, BTW), spruce, douglas fir or even alder (sold as a joinery pine replacement, but in fact a hardwood) all of which cut much more cleanly. If you persist in using non-joinery grade softwoods then the only other thing to try might be HSS cutters as opposed to TCT. HSS can take a far sharper edge than TCT and will often show less signs of tear-out on soft, stringy softwoopds = but beware, it burns easily and the edge is really short lived!

BTW if you rout a cross-grain trench (housing) that close to the edge then the short grain between the edge of the material and the groove wil invariably crumble away at the first sign of stress or loading. Try to groove in the direction of the grain and at least the same distance in from the edge that the groove os wide for better di=urability and smoother sliding of components (as it will be with the grain)

 

[hagheid]

Many thanks Eric.
It's all down to unit price sadly but I could use better quality timber for the sides for sure. Just ordered a Trend TCT & will try that to see if any improvement can be achieved. Regarding the proximity to the edge that's a salient point & I'll adjust the sizing to offset the stress. (No great load anticipated though!) Re- Router speed, any suggestions on the optimum speed to cut this stuff? Re Re- Going with the grain I'll need to see if 7" untreated Redwood stock is economic (these are just Bird Boxes & everything is down to saving pennies!)
I'll cut again & post to see if any improvement is gained
Once more, very many thanks for all the excellent advice

 

[Semipro]

Go to a smaller diameter Bit, make two cuts one for each side of the rebate.
Your bit is running the wrong direction on the side that is splinter.
You also could scribe each side before you cut the rebate
You probably wouldn't have this problem with hardwood but pine is soft

 

[Stick486]

do as Semipro says...
and use a clean sharp bit...
swal the wood w/ sanding sealer or lacquer 1st...

 

[JOAT]

Me, I'd just glue a couple of strips along the bottom for the 'tray' to rest on.

 

[RJT501Win]

All my cross grain box joints I saw.
Set up the sled adjust the blade height and go for it.
Cheers
John T

 

[Cherryville Chuck]

Two cuts as John said and if you are still having problems then use a bit with a downshear cutting action. If using the downshear you may need a groove down the center to give the chips an escape route but that could be made with a saw. That would be 3 passes but you'll find that things speed up quite a bit when the chips can be ejected easily.

 

[MT Stringer]

That looks like a job for a version of my exact width dado jig...and scribe with a sharp knife where the edge will be.

http://www.routerforums.com/jigs-fixtures/49738-exact-width-dado-jig.html

 

[DesertRatTom]

If you have a table saw, you could use a Freud Glue Line Rip Blade to cut the outside edges of the groove, then use a router to remove the rest, using the exact fit dado jig Mike suggested. That blade is a miracle at cutting a clean line in every kind of wood I've tried, including pine.

Scoring the edge with a sharp knife using an exact width dado jig as Mike suggested is what I'd do if I didn't have a table saw.

You might also try a kiln dried douglas fir rather than construction grade stuff.

 

[DesertRatTom]

If you have a table saw, you could use a Freud Glue Line Rip Blade to cut the outside edges of the groove, then use a router to remove the rest, using the exact fit dado jig Mike suggested. That blade is a miracle at cutting a clean line in every kind of wood I've tried, including pine.

Scoring the edge with a sharp knife using an exact width dado jig as Mike suggested is what I'd do if I didn't have a table saw.

You might also try a kiln dried douglas fir rather than construction grade stuff.

 

[CharleyL]

In the first two pictures I see fuzzies, which is common when cutting pine, but can be sanded off, and a chip-out in the end of the cut, which can be avoided by placing a piece of scrap adjacent to your project board and cutting into it so the chipping will happen on the scrap. The saw cut on the end of the board shows more chipping than your dado cut.

In pine I don't think you can expect much better without a sharper router bit and higher bit speed plus a piece of scrap to cut into to avoid the end of cut chipping. You should be able to do better with a table saw and a good quality dado blade.

Charley

 

[hawkeye10]

I will tell you what Stick told me about problems such as yours. Use the very best quality router bits. I was using a bit on the cheap side and getting tear out and I told Stick the bit was sharp and he said you just think it's sharp. He was right. I now only buy Whiteside bits.

 

[Job and Knock]

The only problem with all this advice about dado blades is that the OP is in the UK - and most new table saw sold here simply won't accommodate them, and they can in any case be quite difficult to source. When cutting cross grain housings (or dados as you guys so quaintly call them) I tend to make the housing joints before cutting to length (so as not to leave any unsupported short grain during the machining) and if the timber is particularly bad I'll score the edges of the housing to full depth using a hand saw or a mitre saw before removing the remaining bulk of the waste with a router or with sharp chisels (often quicker when out on site than going to the van and getting a router). Using a spelch block at the cut exit works, but then so does making a small cut in from one end then making the rest of the cut from the other end of the housing.