Replies

1. 
   notDusty | Mar 15, 2005 08:40am | #1

                   Jellyrug ,

        Those cutter heads look as though they are specifically designed to be used with the stock variety of their own cutters . IMO I would not recommend using knives other than those made for that cutterhead. I use and have been using collar knives for many years. the main difference is the collars are two piece a matching top and bottom with a sort of dovetailed keyway . The knives get clamped between the collars , and tightened down with the spindle nut to keep them in place .Most of the collars I use are about 2 1/2" - 3" diameter so the knives are seated firmly in the collar with some protruding out where the detail is. The cutterhead you are talking about only clamps on a very small portion of the knives, making for a less secure system when using longer then stock cutters. I also grind some of my own knives and with some practice a regular wood butcher as myself can learn to be fairly proficient , while not an expert grinder ( by hand and by eye ) I can get the job done and so will you be able to with practice . Only one cutter is actually doing the cutting , I know some may not agree with that but think about it only one cutter can hit the wood first , the others basically cut the chips up smaller and provide balance. I have proved this many times by using a blank cutter without a detail while keeping balance to avoid vibration I was able to make moldings   just fine .If you have a detail you will be using over and over or have a big job for a particular detail by all means have a three wing one piece carbide cutter made and life will be good .Other wise buy a modern lockedge type collar and purchase custom knives or grind your own .

                       good luck and be careful                   dusty

1. 
   joinerswork | Mar 15, 2005 03:20pm | #2

   dusty, and Jellyrug

   A shop I worked in , many years ago, had one of those built-up cutterheads you described. The boss told me, when setting up, "Tighten that nut as tight as you can, then give it another quarter turn." They too used one bit to cut the molding profile, with a blank on the other side to balance it weight wise...  Until a bit broke off, and flew across the shop, bounced off the cinderblock wall and buried itself in the back of a case piece awaiting repair.  If the two knives are ground to match and are set to protrude equally, there will be less stress on each of them.

   Seeing what can happen with an unbalanced (stress-wise) cutterhead makes the extra time and expense of having a pair of bits ground seem worthwhile to me.

   If you are only making a short run of molding, it may be worthwhile to consider using handplanes, or a combination of shaper and molding planes, and/or carving tools (for gooseneck molding) to get the profile you want.  Might be more efficient than going to all the trouble of grinding knives, making jigs to hold the molding, and the "fear factor" of proximity to all that whirling metal, held together by friction. More than one way to skin a cat.

   Regards,

   Ray

1. 
   notDusty | Mar 15, 2005 05:31pm | #4

           Hello Ray ,

                 I got news for you , a knife can break off even if there are 2 equal ones , a story similar to yours took place with a longish knife for panel raising in my pals shop. I totally agree with you , two are better than one , I only wanted to express the fact that even if they are not 100% exactly alike the pattern and quality of the profile can  be quite satisfactory. Often when I tell other woodworkers that I still use steel collar knives for a few profiles they shudder with fright . Aren't you worried they will break off or come flying out , they ask . My standard answer is have you ever broke any carbide ? You know those missing and broken teeth on table saw blades , where did they end up , where did they go ? I have also had 3 wing carbide shaper cutters lose or break a piece off as well . Common sense must prevail at all times , a whirling mass of sharp anything deserves much respect . 20 years ago at an auction I bought about 2 or 3 hundred pairs of knives and much steel for $150.00 and have been using some of them ever since . The white grinding wheels is what I use as well . I learned that at the moment the cutterhead starts  to turn full speed is the time most likely that it will fly out . I have a 6x6 , 3 foot long block of oak that I place behind a power feed and I generally duck down under the table when spinning them for the first time , just in case . In conclusion having a balanced cutter head is paramount for safety .

                               happy shaping                      dusty

2. 
   KeithNewton | Mar 15, 2005 03:36pm | #3

   Jelly, Before you extend those knives up, have you considered whether you can get the same profile with multiple passes with two cutters? You may be able to do it, but sometimes when you start getting into larger cutters which are pushing the boundaries, it starts getting a little risky.

   I have got a couple of the bevel edge type heads, and a locking bevel edge for the larger cutters, and have ground plenty of knives. While it seems like the cost of buying the knives ground to your specifications is kind of expensive, if you buy the steel, then grind your own, you may find that you are spending as much or more to do it yourself when you figure your time into the equation. It is sometimes more cost efficient to just send someone like Memphis Machine a full-size drawing of the profile, and let them do the rest.

   If you choose to make your own, you can cut the blanks with a carborundum or diamond blade. Make the patern out of plastic laminate or something thin stiff and easily shaped. Machine dye the face of the cutter, scribe the pattern shape in the dye, then grind to the mark. I balance my knives on a gram scale to eliminate vibration.

   I use the white Norton wheels with a Kool-Mist system sometimes on a small tablesaw. The height of the wheel above the table controls the bevel angle, and the Kool-Mist additive keeps from rusting the saw table, and from burning the steel. Add a fence across the table like you would use for making cove on the TS, and you have an excelent system for sharpening planer and jointer knives.

   
   

   ---

   Edited 3/15/2005 8:43 am ET by rootburl

3. 
   wop | Mar 15, 2005 07:06pm | #5

        Personally I'd be a bit scared of using that type of cutter head. They were banned here in Europe over twenty years ago. All heads here have to have holes in the knives that fit on to registration pins in the head in a way that even if a screw is not tightened correctly or vibrates loose a knife can't fly out.

       As far as over sizing knives 1/4" is the maximum I would risk and even at that you have a higher risk of breakage. That's for a European cutter head anyway, on that head you have pictured I wouldn't even consider over sizing knives.I've heard way to many stories from oldtimers here about that kind of stuff and the one knife stuff too.

                                                                                                 Philip

1. 
   Jellyrug | Mar 15, 2005 08:58pm | #7

   Wop,

   The corrugated steel knives with these heads are pretty standard over here and regarded as safer than locking collars. Before the knifes get loose enough to skip the 60 degree corrugations, I would expect quite a bit of vibration and be running.

   Do you have an online source in Italy, for your cutter heads, allowing me to look online?

1. 
   wop | Mar 15, 2005 11:56pm | #8

       I have two heads from http://www.omastools.com  one from http://www.finktools.com (but they are a$$holes so I don't use them any more) and CMT also makes cutter heads now in which they use both 40mm and 50mm knives in the same cutter head. I'm sure Frese di Udine (Freud) makes them as well but after bad experience with them I avoid their products.

                                                             Philip

     A custom ground set of two knives for my omas heads ,50mm, any profile I draw costs me 35 euro ($46). 60mm costs 5 euro more same head.

   Edited 3/15/2005 4:59 pm ET by wop

   Edited 3/15/2005 5:00 pm ET by wop

1. 
   Jellyrug | Mar 16, 2005 12:16am | #9

   Wop,

   Thanks, I have emailed Omas tools, as the prices are good and shipping should not be that expensive.

   By the way, I don't speak the language, but I have been to Italy several times, about four times a year, doing business with Sasib in Parma, worked with San Peligrino, and Tetra Pack in Modina. I use to do bike racing in the Venito region once a year also.

   You have a nice country and love the food.

1. 
   wop | Mar 16, 2005 12:34am | #10

       Yeah! I raced until about 12 years ago too ,Milano area.   Then time for training just wasn't enough to remain competitive so I quit. Also here the rules allow guys who have gone professional and then drop out to go back to racing amature. When you get one or two of these in a local race it takes alot of fun out of the race.

                                                                                         Philip

      San Pelligrino is also close to home I was up there Saturday (about 40 km from here)

4. 
   Tao | Mar 15, 2005 08:55pm | #6

   Well, they're corrugated-back knives, which helps a lot with safety.  The gib design is different from what I have worked with, but it appears to be self-tightening. The design is not all that dissimilar to the way jointer and planer knives are held.  I'm more accustomed to corrugated bevel edge collar knives on shapers, and this type of cutterhead for corrugated back steel on molders:

   http://www.cggschmidt.com/cutters.html

   The amount of safe projection depends on the thickness of the steel (common thicknesses are 1/4, 5/16, and 3/8), the depth of the cutterhead slot, and the quality of the steel.  I rely exclusively on the recommendations of the manufacturer as to the amount of projection on my profiles.  Obviously, thicker steel will allow greater projection, and I've run some pretty deep profiles with 3/8" steel.

   Allowing the steel to stick out above and below the cutterhead is bad practice, but in a pinch you can get away with 1/4" top and bottom if your machine has clearance.

   I like the bevel edge collar knives with corrugations on shapers because I can index the knives fairly precisely to a rub collar, so I get better consistency in template work. This can become important after a few sharpenings.  With corrugated back knives, your cutting circle changes with each sharpening, which is no problem on a molder - you just move the whole cutterhead to compensate. Collar knives use a lot more steel and so cost more, and the knives are supported only at the edges, which can conceivably be a drawback on tall profiles.

   Michael R

1. 
   Jellyrug | Mar 16, 2005 09:26pm | #12

   Woodwiz,

   Thanks, that was good information.

   I phoned the supplier, as per the link you posted. They suggest a maximum of 13/16" projection, using 1/4" steel and their head. Problem is the charge $177 for a set of custom ground knives, which is fine for those running a production shop. For me, I would rather hand grind.

    

1. 
   Tao | Mar 16, 2005 09:51pm | #15

   I phoned the supplier, as per the link you posted. They suggest a maximum of 13/16" projection, using 1/4" steel and their head. Problem is the charge $177 for a set of custom ground knives, which is fine for those running a production shop. For me, I would rather hand grind.

   Schmidt's always pretty expensive, I think.  I just posted the link to illustrate the type of head.

   No doubt you've got someone locally who can sell you the steel or make you a set of knives.  If you can't find somebody capable under "sharpening" in your local yellow pages, Email me and I'll give you a couple of addresses where you can mail order.

   Michael R

5. 
   frenchy | Mar 16, 2005 08:44pm | #11

   I have that same shaper and while I currantly use cutters that are 5 3/4 inches the idea of using a cutter spinning as fast as that does counting only on thwe friction generated by a pair of grub screws would scare me too much..

     can you use part of another profile instead?  could you use for example C2216Z for example? 

1. 
   Jellyrug | Mar 16, 2005 09:36pm | #14

   Frenchy,

   I do a lot of Victorian, Georgian and Romanic styled work, and some of the preferred profiles are close the goose neck used by Lonnie Bird, but a bit bigger, see the link below. So I'm looking for one custom cutter which I will use often, to do the job quickly. If you look at the profile, I believe there is no other quick alternative.

   About the head, it does nor rely on friction, but has 60 degree corrugations on the back of the knife, engaging with matching corrugations in the head. The only risk is making sure that the cutter will not break, due to how far it extends and the profile.

   http://www.lonniebird.com/DSCF1029.JPG

    

6. 
   kipper | Mar 16, 2005 09:33pm | #13

   Jellyrug

   Personally I'd advise against exceeding the cutter dimensions recommended by manufacturers. If you need a bigger profile area buy a bigger block. or make two passes with different blocks/profiles. Just remember the biggger the block the more difficult it can be to brake to a stop. Does your machine have any sort of limit on block diameter or weight?

   I'm in Europe, so the pinned Euro-style safety block is pretty much mandatory on hand-fed shapers (spindle moulders) here (see Whitehill'c catalogue at http://www.whitehill-tools.com/holding_page/Whitehill.pdf for some Euro-style tooling). We also have to fit limiter knives for safety, but kickbacks aren't severe with this type of block and they do seem to give a better finish, so it's not all bad. The downside is that a machine to grind cutters AND the limiters cost a small fortune ($8,000 and up!) There is, however, a company up in Canada called Viel who make a small benchtop profile grinder (see http://www.moonssawandtool.com/browse.cfm/4,446.html), but even that basic machine costs $750. Another approach may be to use something like the Armadillo cutter block system (assuming there is a distributor in the USA) which uses a series of differently-sized interlocking rings which can support knives of widely differing profile and where the cutters can be ground to any height you need (within reason) - however you need to have a profile grinder for those, too.....

   I do regret the passing of the simple to grind French cutter, where a flat cutter simply slotted through a specially slotted spindle, but,  boy they could be really "interesting" if the got loose (and they did from time to time).

   Possibly the thing to remember is that a router cutter weighs in at a few ounces to maybe half a pound and is generally less than 3in in diameter - a shaper block is a lot bigger and heavier and comes with a substantially greater destructive ability. It pays to use within the specs.

   Kipper  

    

    

1. 
   Jellyrug | Mar 16, 2005 10:08pm | #16

   Kipper,

   Amen, looks as if we have to play catch up over here, as to my knowledge this is not available in the US.

   What more could one ask for, Molder heads manufactured to recognized and published standards, and 20 Pounds Sterling, for a set of 4" cutters.

   I will contact them, do you know how much they charge for custom grinding?