50mm shaper insert knive in 40mm insert head?

[alex grams]

I have an insert shaper head (Rabbeting and 40mm (1-37/64") profile cutter head) (http://www.cmtutensili.com/show_items.asp?pars=HK~694.020~2) and the profile I need to make is with a 50mm knife. I don't see where I can get a 50mm head, but just wanted to run this by someone who knows better if this is safe? It is going to be a modest cut with a rub collar on a jig, but just wanted to know if anyone can point out if this is an unsafe option and I need a larger cutter head, or if this is the best way to do it.

The main thing I noticed when I mounted the 50mm blade on my head is that the blade sticks out decently further than the 40mm blade (probably about 3/16 - 1/4 more).

Thanks in advance.

[Jeff Duncan]

I'm not going to tell you whether it's safe or not, that's a judgement call I'd only make knowing every detail. I have run corrugated with a fair amount of overhang, but the knives were much thicker than Euro block knives.

FWIW I believe Amana offers the 50 mm head, IIRC Amana's is called the Profile Pro.

good luck,
JeffD

[Mark Wooden]

I have a Leitz head that's the same size. Those knives are fairly thin carbide; they need support because they're brittle, probably not a good idea to run them in the smaller head. Can you make one pass with the 40 mm knives and then raise the head to complete the cut?

[Peter Quinn]

I don't think you have any issue if these are stock knives from a euro block system, the 50MM system knives should work with the 40MM head. The 40MM head is 40MM tall, so there is no knive projection above or below with standard knives. With the 50MM knife you are running about 3/16 beyond the head, that shouldn't be a problem for a 4MM thick knife IME. If these were ground for you the grinder should not make anything that is beyond the systems capacity in terms of projection. Amana's 50MM head is for special 5.5MM thick knife blanks and is not part of the standard euro block system, so that won't help. I'd take light cuts with any new shaper operation just to be cautious.

I just dug up a page from CMT's site, here's a link, shows the 40MM head taking either 40 or 50MM knife blanks.


http://www.cmtutensili.com/show_items.asp?pars=HK~692~2

[J.R. Rutter]

Steel should be OK, but I have not had good luck with carbide projecting more than 1-2mm past a backer.

[Mark Wooden]

Peter, that's not the head that comes up for me with Alex's link-
http://www.cmtutensili.com/show_items.asp?pars=HK~694.020~2
I may be reading it wrong but I think the knives are 1.5 mm thick, a little thin to run unsupported, they may snap off.

[J.R. Rutter]

I confess that I didn't look at the original link, and just threw out some generic advice. Those are standard thin carbide knives - I would not run wider!

[Peter Quinn]

Peter, that's not the head that comes up for me with Alex's link-
http://www.cmtutensili.com/show_items.asp?pars=HK~694.020~2
I may be reading it wrong but I think the knives are 1.5 mm thick, a little thin to run unsupported, they may snap off.

Im guilty of not looking at the original link either. That head looks interesting, seems it spins either the carbide chips for rabbiting with spurs OR the 40MM profile knives if Im reading it right. The 1.5 mm carbide certainly can't run unsupported, but I suspect the 40MM knives for profiling are thicker or that feature would be of little use. Better for Alex to contact his CMT dealer for clarification. Are the 50MM profile knives 4mm thick Alex? If so I still believe you are safe running the 50mm X 4MM HSS knives on that head.

[alex grams]

yes, the knives are 4mm thick.

It is this pair (http://www.amazon.com/gp/product/B000P4JKQG/ref=oh_details_o03_s00_i03?ie=UTF8&psc=1) that I am profiling:

http://ecx.images-amazon.com/images/I/41CG0nSmg3L.jpg

[Don Sundberg]

Here is the head for it.

http://www.amazon.com/CMT-692-100-31-4-Inch-Shaper-Cutter/dp/B000P4LMVC

It looks like the 1" & 1.25" bore heads are rated for the wider cutters. Looks like these knives are designed for a 40mm thick head.


I believe my head is an Amana.

[david brum]

I'm anxious to find out what CMT says about your combo head. If it actually takes 40/50mm profile pro cutters, it seems very versatile.

[alex grams]

I did a little ore research and apparently the head I have with my set is listed as being able to take 40mm or 50mm knives. Now I just need to get a 120mm rub collar since the 50mm knife sticks out further than I expected.

link to cutter head I have (http://www.cmtutensili.com/show_items.asp?pars=HK~692B)

[Mark Wooden]

Oh, ok, different animal.........

Seems to me that unless the holes index the the longer knives flush to one side of the head -top or bottom- you'll need a spacer between the head and rub collar to get past the amount of the knives sticking out.

[alex grams]

Fortunately I have spacers on hand, just not the 120mm collar.

[Peter Quinn]

The aluminum rings with steel bearing set up work pretty well IME, I've got the amana version I use with a 120 MM rabbit head for flush trimming, much cheaper than a solid bearing that size iir, and fairly inexpensive to add other sizes.

[alex grams]

I got the same thing Peter. Though I had a similar profile in 40mm that I measured cut diameter before I ordered the inserts. The. I discovered when I ordered and received the 50mm blade that it sits out 5mm further on each blade, so my 110mm collar wouldn't work, so I have a 120mm on order.