What can be done on CNC?

[alexkuzn]

I wonder if anyone tried to make a blade with mini CNC Vertical Mill.
I want to make a blade with integral bolster. Do you know if any one did it before?

Thanks,
Alex

[SharpByCoop]

Hi Alex,

Welcome to the forums. Good question... or rather two:

Integral knives (in this case, milled out of one piece of stock) are a mainstay in the knife world. Not as prevalent as a build construction, but fairly common nonetheless.

Makers who specialize in this type of knife are: Ricardo Velarde, Dietmar Kressler, Edmund Davidson, among others.

Here is Ricardo's website to see just how beautiful this can be done. Also look at this thread to see another member who did similar work.

You don't need a CNC to accomplish what they are doing.

You DO need a CNC to accomplish what RJ Martin and Larry Davidson are doing.

We didn't even start on forged integrals... That's an even larger area!

Goodluck in your own quest.

Coop

[alexkuzn]

Is there a tutorial or at least some tips on doing integral bolster?
If it's not extremly difficult I want to try.

[Ray Rogers]

I have a CNC mini-mill, a Sherline conversion. The worst part of the job is that it will take a great deal of time. A mill this small cannot move much steel at one time so the bigger the blade and the thicker the stock the longer it will take (obviously).

Due to the limited table travel you will have to stay with fairly small blades, which helps with the speed problem. Then, you'll have to build fixtures to securely hold the blade, especially when it's time to turn it over and do the second side.

After the blade is done you will still need to spend a good deal of time on the belt grinder cleaning up the mill marks. The mill will not leave a smooth clean finish on the steel especially where the steel 's profile is curved or slanted from the horizontal. Chances are, with a little practice, you could have ground the integral blade on the belt sander and got the same result in far less time but if you enjoy CNC programming it can still be a fun and challenging project.

Now, before everyone jumps on me and says, 'Yeah, but Maker X makes fantasic integral blades on a CNC mill' let me oint out that I am not describing Maker X's CNC mill. I'm talking about a micro mill which may even be smaller than the mill that Alexkuzn owns. My Sherline only weighs about 25 pounds - it's a very small mill and where mills are concerned size and weight determine what kind of jobs the mill can do ....

[alexkuzn]

The mill I have access to http://www.flashcutcnc.com/html/mach_2000_5400.html
is times bigger than Sherline so I might have better luck with it.

Working in 3-D CAD program is fun and what I like the most that you can
render your drawings and picture of the knife looks like real thing - with woden handle, shiny steel blade etc.
You can move it, rotate it, etc. so before you even start on your knife you can play with it, look at it from different angles and make sure you like it. If not - it's easy to modify it.

Next stop would be to try make it on CNC.

[SharpByCoop]

I'm sure interested to see what you come up with. Keep looking into it.

BTW, it is customary to offer a single word of thanks when folks go out of their way to answer questions. Especially if you are new. We try to maintain a 'homey' feel around here and simple courtesies go a long way. I see you are new, and I appreciate your questions. Appreciate our answers.

Please don't take me the wrong way, Alex. I am just helping you along still. We're cool.

Coop

[alexkuzn]

I really do appreciate you guys answering my questions. I always wanted to make knifes but never had time, equipment or money. This forum spared me of many mistakes I could make.

It's nice of you to answer newbies especially considering that some questions we ask might sound stupid for the experienced in knife making.

Anyway. if anyone can guide me on how to start with integral blade on CNC I would appreciate it. I am concern about clamping blade while milling so it doesn't flex.

[Ray Rogers]

Actually Alex, the machine in the link you provided is a Sherline mill will the Flashcut CNC conversion. If you look towards the bottom of the page on that link you'll see that this is true. Anyway, it's a good machine and lots of fun to play with as well as educational.

I have some highly skilled machinist friends who have million dollar CNC machines. One of them decided he just had to make some folder blades for me and we did the CAD/CAM thing, it was a lot of fun. But, even with that machine we still had to do a lot of work on the belt sander to clean up the bevels. By all means, do whatever you feel compelled to do with CNC but don't overlook your grinding skills.

There are books that you can find on building fixtures to hold things on a mill table but they are probably more than you need. It will take some trial and error but it isn't that hard to do. The basic idea is to get some blocks or plates of aluminum and shape them however you have to in order to support whatever shape needs to be supported. Use clamps to hold it all together, or drill extra holes in places that aren't important and put screws through the holes. You can make clamps in special shapes from aluminum according to your needs. Another popular method os to epoxy a part to the fixture and dissolve it off later. A mill that small can't take deep cuts in steel, .025 is usually good, so it doesn't take a huge amount of clamping force to keep things from moving. Be sure to use sharp cutting tools because if it gets dull it will start to push the metal instead of cutting it and that will damage something (either the cutting tool or your part usually). Use an appropriate cutting fluid, that helps your cutters last longer.....

[Kevin Wilkins]

You'll be wasting your time trying to make an integral fixed blade knife on the miling machine you have. It's way too small and not nearly rigid enough to do the job. You need a machine that weighs at least 500 lbs plus and has a substantial tool holder to handle the stress of milling steel. An old Bridgeport knee mill will do it and the China clones also. Even if you limit your cut to 0.05mm it would take hours and hours and the result isn't worth the trouble with your mill. You can also easily damage the spindle or overload the elctronics.

As an exercise in designing and programming, try making a simple integral from light alu or plastic. You should be able to get that to work.

Also a good rule of thumb is if you don't have the skills and experience to make the part on a conventional machine, you won't be helped with a CNC machine.

Those purty cad renderings have about as much relavance as arcade race car simulators have to really driving a race car on a track unless you have the experience and skill to interpret them correctly. Basic machinist's skills are as much a prerequisite as basic race driving skill are. I am starting out in the world of CNC this last year and I can easily make a simulation that looks great running on the computer but where my machinist skils tell me that by looking at the numbers, actually sending the programm to a machine would cause a massive crash and possibly even severe damage to a machine weighing 3000 lbs.

Ray made a number of very good points in his post and I hope you will heed them.

Say Ray, if your friends weren't able to mill you an integral without heavy tooling marks then they weren't up their game.
The machines out there today can mill finished parts that require almost no further finishing. If you get a chance to see even routine molds used in industry today you will flip out. Of course just the cutting tools needed will cost as much a nice new car... not to mention the milling canter and the software needed...