why are reversible routers and bits not a thing?

[deema]

I don’t buy this suggestion of cutters scraping, Putting a modern ground cutter in a French head will not result in it scrapping.
A modern block sets the cutters on an angle to place the cutter tips on a line that runs through the exact centre of the block. The profile in the cutter is ground to take into account the angle the cutter is mounted. It therefore produces an exact replica. French heads have no advantage or can do anything better than a modern head.

French heads were often not tightened up sufficiently, or, cutters were stacked. This resulted in them releasing from the head when they shouldn’t becoming high speed missiles imbedding themselves in what ever was close……yuk! Modern blocks prevent cutters from escaping by wedges and either serrations or pins. French Heads don’t have limiters, so if you get something you shouldn’t caught by the cutter it tends to pull it in chopping a lot more off.……like hands. This along with other daggy practices created the bad press the spindle gained.

 

[Spectric]

I don’t buy this suggestion of cutters scraping, Putting a modern ground cutter in a French head will not result in it scrapping.
A modern block sets the cutters on an angle to place the cutter tips on a line that runs through the exact centre of the block. The profile in the cutter is ground to take into account the angle the cutter is mounted.

So it is more of a shearing action than just scrapping, like the difference between a spiral cutter block and a helical cutter block in a P/T.

 

[niall Y]

Yup to a point. That flips the profile so if you flip the part to match you are cutting in the same direction as before the flip and gain nothing.

Pete

Granted, it won't work with cutters with an asymmetric profile, but with those with a symmetric profile , it will. Of course, there is the problem - as you have already noted - of the screw threads undoing, but hypothetically speaking - as in "don't try this at home ,children"- It will work

 

[johnnyb]

a French head has no rake angle. he grinds clearance on the edge. it would be possible to introduce rake by grinding back the face of the cutter( bit like a carbide lathe tip) but at that point the heath Robinson nature of the entire setup becomes apparent. I'm not advocating french heads just chatting in context. to me a thousand pieces of fancy aren't worth even a little finger!

 

[johnnyb]

it's not a shearing action but shearing may happen as he was moulding on a " dumpling" using solid twisted wood. but the cut is strictly in line with the spindle.

 

[johnnyb]

he addresses another interesting thing in that the old tangent handrail books deal with getting the twisted square/ rectangle. only touching a little on making that a handrail.using carving chisels thumb planes etc .

this skill set still has a tiny relevance stateside as quite a few new builds have real fancy staircases and wealthy folk like this stuff and there's more money (and space)across the pond( generally)

 

[deema]

a French head has no rake angle. he grinds clearance on the edge. it would be possible to introduce rake by grinding back the face of the cutter( bit like a carbide lathe tip) but at that point the heath Robinson nature of the entire setup becomes apparent. I'm not advocating french heads just chatting in context. to me a thousand pieces of fancy aren't worth even a little finger!

My Bad, your absolutely right, in my naivety id totally overlooked the leading face of the cutter.

 

[deema]

he addresses another interesting thing in that the old tangent handrail books deal with getting the twisted square/ rectangle. only touching a little on making that a handrail.using carving chisels thumb planes etc .

this skill set still has a tiny relevance stateside as quite a few new builds have real fancy staircases and wealthy folk like this stuff and there's more money (and space)across the pond( generally)

Continuous Handrail work was considered the pinnacle of wood working according to my father who was a master joiner. I was dubious, and searched for a book on the subject on how to layout to make the sweeps which I managed to find. Now maths is one of my strengths, and I have an Engineering Degree, but Holly cow, the maths behind getting the sweeps taxed my brain. Im sure if you had someone to show you how to do the projections its far easier to pick it up, but the boys needed both brains and hand skills to layout and making perfect sweeps……no wonder continuous handrails were always seen as the utmost luxury.

These days CAD to produce the templates if doing it by hand takes all the ’hard’ work out of it.

 

[johnnyb]

to be honest I'm not entirely sure how such poorly held cutters ever became the norm. it's that disregard for life and limb so common in years gone by. I always figure some jobs have inherent dangers that only an extremely nanny mentality can mitigate. this happened in the late 60s and 70s with mining. unfortuneatly joiners shops are small concerns and safety was a secondary consideration