Hi Brent, in my opinion the cheapest option I have may only be the cheapest option I have, not the best.😀Originally Posted by brent stanley
Regards, Rod
Contributor
Hi Brent, in my opinion the cheapest option I have may only be the cheapest option I have, not the best.😀
Regards, Rod
Contributor
Kick backs have a reason to cause them. Do something wrong and anything can kick back, throw a pieces of wood at a jointer head and it will kick back. Throw a piece of wood at a router bit and it will kick back.
There is MECH and MAN what is the difference in why one is okay to hand feed and one is not. Its a logical question.
Whats causing the kick back? You are fine till suddenly you arent? what does that mean? You are feeding wood into a cutter, there are no reasons for that to kick back.
You'll probably find the split adjustable groover will give excellent results though discs with more mass will perform a little better with heavier cuts. Not many small adjustable groovers today have shear cut knives whereas dedicated tenon discs can, so they may be superior in the bigger picture. But if something you already own is already giving results you like, it's the cheapest (and "best") solution all things considered!
Last edited by brent stanley; 02-11-2022 at 7:42 PM.
MAN is kind of like a seat belt in that you don't need it until you do. A MAN rated block will kick back if you do something wrong but the kickback is less likely to happen and it will be less severe if it does. It also won't auto feed you hand if you erroneously get it in there. Makes the difference between losing the tip of your finger and hamburger hand. In Europe, it is deemed acceptable to hand feed a MAN rated tool because they offer a layer of safety in addition to proper training.
I don't have data to support it, but I would guess that the majority of historical kickbacks are a result of someone doing something wrong. Either because they were not trained, trained incorrectly or just human and goofed up....because they're human. There are also scenarios where the unpredictable happen and things go south and there's a kickback. MAN rated tooling just gives another layer of safety. I've never once needed my seat belt but still put it on every day.
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Warren, for insert tools with the thin carbide cutters the difference between MEC and MAN is hardly noticeable since the cutter projection from the body is about the same. It’s mostly in the gullet width or sometimes if a large slotting cutter or some kind of special insert is mounted on the body.
the head on the right is a MEC 320 diameter tenon head and on the left a MAN tenon head about the same size. The MEC tool is off a mechanical fed window machine but I have no problem running it on the shaper. The MAN one will cut less of your fingers or hand off if you get in the cutter. I don’t plan on getting my fingers near any of these. The MEC cutters actually clear chips better and have a little less pushback than the MAN.
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Because power feeds are removable they are considered MAN feed and any Tenoner without a powered sliding table is considered MAN. Don’t kid yourself the experienced hands in Europe break the rules occasionally. In reality with a proper set feeder these tools are safe on the shaper. Same with a well clamped sliding table.
I’m surprised you think the corrugated heads have less pushback. That has not been my experience. I don’t like doing curve work with corrugated. Done it a lot in the past but not with deep cuts anymore. We set up a Soukup machine in a shop where a employee lost his arm up to his elbow hand feeding a corrugated head. I don’t know all the details but I guess they were lucky to have a EMT on staff to stop the bleeding.
Here is a top of the line limiter cutter from Leitz for deep profiles. This cutter has less pushback than any other cutter this size. 5mm high quality HSS, shear cutting and a high precision fixing system. I tried one of these in the Martin factory a while back. The cutters though take a long time since they have to come from Germany. When I bought this they thought they could make the knives here but not so. Cuts like a hot knife in butter!
I would add that I know most here are hobby woodworkers or have limited experience in shaping. Until you have more experience using limiter cutters and starting with smaller diameter cutters is a good safe idea.
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Last edited by Joe Calhoon; 02-11-2022 at 8:35 PM.
This is an insert head (Byrd) that is not MAN rated due to the perched cutters effectively creating a deep gullet in front of the cutter like Joe described. I've designed some shaper tooling and have the whole technical documentation that describes what is required for MAN rating. I find it fascinating, but many would find it a cure for insomnia!
The projection of the individual cutters matters but also the whole form of the cutter all the way around the circumference. There are a lot of devils in many details. More cutter projection is permitted in round form blocks than limiter style blocks for example, for obvious reasons.
Joe is that Leitz cone head also shear cutting??? The knives are in there on an angle? That's very cool, I'd love to see the wedge block/securing apparatus on that head.20220211_202207.jpg
Last edited by brent stanley; 02-12-2022 at 1:53 PM.
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