50mm double bearing template router cutter

[Mr T]

Hi Oscar

I would feed as in "B", but not because of the direction of the big stripes, more because of the finer lines in the background which trend in the same direction. Many people are confused between grain and figure, the big stripes are figure the finer lines indicate grain direction, often they are contrary to each other but not in this case. I can't find a piece in my workshop that illustrates this at the moment but you can download something about it here http://www.christribefurniturecourses.com/index.php/figure-and-grain/ I'll see if I can find a good illustration tomorrow.

In principle the feed direction should be such that the direction of travel of the cutter is up the hill of the grain.

Chris

 

[Mr T]

A few years ago I posted about a chair making project which started with making and adjusting a full size mock up https://www.ukworkshop.co.uk/forums/vm-chair-project-t87767.html

That's just superb.

The crest rail is a work of art, and how it's made is pretty clever too!

Thanks for the compliment Custard, praise indeed from a maker of your calibre.

Chris

 

[OscarG]

A spiral bit worked with the grain will give you the best result of all, in many cases it's virtually finish ready straight from the tool.

To be clear, when you say with the grain, would that be B)?

I really do appreciate your reply, this grain stuff I find really hard to get my head round. I'm still scared of my table router since it launched a 4kg piece of ash at me!

Think i'll invest in one of those spiral bits from Wealden.

 

[OscarG]

Hi Oscar

I would feed as in "B", but not because of the direction of the big stripes, more because of the finer lines in the background which trend in the same direction. Many people are confused between grain and figure, the big stripes are figure the finer lines indicate grain direction, often they are contrary to each other but not in this case. I can't find a piece in my workshop that illustrates this at the moment but you can download something about it here http://www.christribefurniturecourses.com/index.php/figure-and-grain/ I'll see if I can find a good illustration tomorrow.

In principle the feed direction should be such that the direction of travel of the cutter is up the hill of the grain.

Chris

Many thanks Chris, I didn't realise the difference between grain and figure.

I've looked at your .pdf, ha...i'm now a bit confused!

You can imagine running your finger down the slope of the cut will be smoother
than going the other way. (there will be a knap to the surface). When planing or chiselling
wood you want the smooth cut down the slope, this will make the cut easier and also give
a cleaner almost burnished surface (if your edge is sharp).

I thought I had to rout going uphill but the .pdf suggests the opposite?

Sorry!

 

[Mr T]

Hi Oscar

In the example I mention cutting the bundle of straws at an angle and running your finger down the slope of the cut feels smoother than running up the slope, that is the way you want to cut. I can see that it may be confusing as you are told to work up the angle ot the grain. Perhaps the illustration below will help.

At the top is represented the bundle of straws which represents an uncut tree trunk (2 dimensionallly).

Then the bundle is cut through at an angle. If you run your finger down the cut slope it will be smoother than going up, you are working with the lay of the straws/fibres and would plane in that direction.

To spot the grain direction in a board you need to look at the side adjacent to the surface you are cutting. The bottom picture shows the bundle rotated so you can plane the top surface the straws/grain slope down from left to right, you would plane right to left up the slope of the grain.

I hope that helps.

Chris

 

[OscarG]

[ *dink* ]

That's the sound of the penny finally dropping!

Ah it finally makes sense, thank you so much for your patience! Star man!

So the cutter on the bit needs to be moving in relation to the wood the same way you'd plane it?

 

[Mr T]

Exactly!

 

[woodworm2017]

Can you look at this piece of wood and examples below and tell me which way you'd orientate the board in order to achieve the best/safest cut on that top edge, a) or b).

This is the wood...

Would you pass it through router like a)

or place the template on other side, to turn board upside down and reverse the grain... b)

So A or B?

B is the orientation that will give you the cleanest cut. On some projects you can screw the template to the workpiece (dropping the screws into areas that will subsequently be chopped out for mortices for example), or you can carefully apply good quality double sided tape. In these circumstances you have a workpiece/template assembly that can be flipped upside down if you're using a router bit with a bearing at each end of the cutter (I hesitate to call it a "double bearing bit" because there are also copy routing bits that have two bearings side by side to give an increased bearing surface). A good way of thinking it through is to imagine you're copying a perfect circle, you'd make four separate cuts, one in each quadrant, with two cuts made with the template on top, and two cuts with the template on the bottom.

Another alternative is to use spiral copy bits like these,

https://routercutter.co.uk/2-2-compress ... al-pattern

they're certainly not cheap, but because of their sheering cut they tend to produce acceptably clean results both with the grain and against the grain. In fact you can find spiral bits with a bearing at each end, Wealdens do a very good one at a slightly more affordable price. A spiral bit worked with the grain will give you the best result of all, in many cases it's virtually finish ready straight from the tool.

hi custard
thanks the info i got from you is phenomenal.... specially the grain direction bit is very well explained in detail. no book i have read gives such detail. the cutter i am using is from wealdens i believe its called Easi tip one that you can change cutter blade. i did look into compression spiral cutter but wasn't sure specially length of the cutter is short in them and i made my temple in 18mm plywood and what i read in the books it is better to use top and bottom bearing cutter to get out of changing cutter when direction of the grain changes.

 

[Mr T]

hi custard
thanks the info i got from you is phenomenal.... specially the grain direction bit is very well explained in detail. no book i have read gives such detail. the cutter i am using is from wealdens i believe its called Easi tip one that you can change cutter blade. i did look into compression spiral cutter but wasn't sure specially length of the cutter is short in them and i made my temple in 18mm plywood and what i read in the books it is better to use top and bottom bearing cutter to get out of changing cutter when direction of the grain changes.

I also use the Easi tip., with standard cutters the cut will be narrowed when it's sharpened meaning the workpiece ends up a smidgeon wider than the template. With the easitip the cut remains consistent.

Occasionally on very thick pieces I have, using a double ended bearing guided cutter with the top bearing removed, routed in one direction using a template then flipped the piece and made a second cut with the replaced top bearing on the previously shaped part. This can give me a little extra depth of cut by not using the template.

Chris