Wayne, that was extremely well-said.
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The slotted collars are probably not even made anymore. Twenty years ago there were only two makers. But I don't see
anything inherently more dangerous about them. A lot of shop owners are just not up to enforcing rules. Few fingers are lost to flying knives compared to the number just thrust into them by the wounded.
two makers and one stopped long ago. Had to convince him to talk to me, likely law suits and bad memories. Once he knew we learned on them he talked for an hour and sent me the original engineered drawing for the adjusting screw.
Schmidt still sells them and were one of the two makers Wisconsin the other. I dont call them lock edge but serrated. Safest when the steel is cut full length of the slot. Lots of people used to cut the steel half way or a bit more. The longer the knife is in the slot the less centrifugal force there is on it. 3,500 Max RPM
I don't think you guys quite get the difference. The cutter blocks I showed are NOT lock edge or serrated or anything. The collars are not clamped independently of the spindle nut. It is just two pieces of square edged tool steel in plain slots clamped by the spindle nut. Torque the nut a fraction not enough, get sawdust under one cutter etc and you could be shaking hands with your preferred deity. Serrated edges were something I must have skipped because we dumped the slotted collars and went straight to chip limited solid cutters. Set up time dropped, cut quality went up and so did productivity.
Finally, I know I have said this before but I really don't actually care what everyone does in their own workshops with regard to safety. That is your choice. However, be responsible in what is advocated as best practice. Safety is not a test of personal worth. As someone earlier in this thread, 'MAN' in this context is short for 'MANUAL FEED'. Cheers
And your point is? The research has been done and the next level of safer methods involves the complete removal of the human element in the operation. That's already here. Robots and CNC. The current tooling is not the problem and there is enough safety equipment and procedures in place to protect anyone with a brain and the many without. This mostly because of the nanny state we live in and the fact that most don't take responsibility for their actions. It comes down to you can't fix stupid.
When you receive training in Europe it often includes all kinds of gory images when they discuss safety and let me assure you....you still want to take full responsibility for your actions even with MAN rated tooling. The damage done to you is greatly reduced and can mean the difference between a couple of weeks of unpleasantness and a lifetime of deformity, but MAN rated tooling does not absolve you of personal responsibility that's for darn sure.
That's interesting Wayne because I've heard the same thing. Talking with shop owners around Europe I find that some of them admit they were all worked up about it in the beginning, but 5 years later were wondering what the fuss was about. Everyone had to do it so there was tons of competition in the tooling market and prices benefited from that. Costs of limiter knives was offset by increases in productivity and insurance premiums benefitted too.
A MEC vs MAN tooling discussion ( at least as it relates to hobby guys ) should also include picking tooling that is appropriate for the machine. I've seen a lot of threads talking about 1.25" tooling on light duty machines with small quills and bearings or hollow draw bar spindles. A Hammer machine can't use all the tooling a 700 can and a 700 can't use all the tooling a 900 can, etc. Just because tooling has a certain rating doesn't make it appropriate for the machine. I started out running light shapers with tooling that now scares the crap out of me. When I decided I should learn more about how machines are built, it changed how I work and the tooling and machines I use. Commercial applications are different, but as a hobbiest, I've not hand fed a shaper in years other than a couple of test inches during set up. Dave
Exactly! Excellent point. It's very difficult to know from the outside what can be run and what can't if you don't know the build of the machine, or even how to interpret the build of the machine.....if the machine has recommendations it's not always complete or up-to-date with modern tooling. If you run tooling that's too big and all that happens is you ruin bearings quickly, that's not the worst that can happen.
I would be interesting to compare side by side, but I only have one set of college course material from when I went to England a while ago and it's hard copy. I would ask Rod Sheridan. He prepared course material for/with Felder in Canada and probably has a more complete cross section of offerings.
Wayne, I've used both types and prefer the smooth ones as they are more versatile in regard to where the bearing
is. The steel in the collars is soft and easily damaged ,I guess that gives them a little spring. Biggest problem is the unskilled over tighten them and "lose" some hold ....so they compensate by tightening more. The video leaves out an
important step . After the knives are positioned the spindle nut should be tightened with FINGERS . Then the fingers try to move the knives,if they succeed the whole deal is checked to find the flaw. The wrench should never be used unless the
finger tightening makes moving the knives with fingers impossible. Then the wrench is used is used in a manner consistent
with knowing that the steel is soft. Over tightening means some steel is "lost" ,so the unskilled tighten more. The only
problem with collars is allowing the unskilled to use them.