Skiving Machine Inquiry

[Ferg]

This may be considered "High-Jacking" this thread but I believe some information I have gathered may be useful to some folks buying one of these machines.

I have read numerous articles/tutorials, watched about every video I could find, most several times, still did not have the finite information everyone needs

to properly adjust these machines.

My machine has the grooved steel feed roller on the bottom. You have probably noticed the feed wheel has the same radius the Bell Knife has.

Vertical adjustment for the feed roller is to the rear of left end while the angle of the feed roller is adjusted by threaded adjuster to the front on left end.

Adjust the angle so the feed roller fits the curve of the knife. You can adjust the proximity of the roller to the knife with the rear adjuster. Use a couple pieces of copy paper about 1/2" wide to slide between the roller and the knife blade. one toward the back, one to the front of the feed roller. Adjust the up and down until the paper strips just slide between knife and roller. This is almost perfect adjustment for chrome tanned leather that is fairly soft from 1.5oz. to 4oz. Lining leather for instance or Kangaroo leather. The top roller I use most often is tapered from back to front. You will learn quickly that adjustment of where this roller meets the bell knife determines how wide the skive will be. With this leather I bring the top roller close enough to the knife that you can only slide that piece of copy paper between them. Don't allow the roller to rest on the knife, you might distort the edge.

There is a spring on a hook mechanism to the left rear of the machine. This adjusts the amount of pressure required for the feed roller to hold the leather being skived, against the bell knife. Light weight leather I place this in the second notch. Thicker/harder leather I may pull the spring all the way out to last notch. Also: Some belt leathers, among others, are very hard temper. You will need to lower the bottom feed roller slightly to allow leather to go through the knife.

There are small oiling holes on the shaft of the lower roller, oil them frequently. they are a little difficult to access, be creative.

That is a few items that may help some of you anyway. Let me know if I can be of further help.

ferg

[Trox]

Hi Blake,

the way I see this. A bell knife skiver is a must when you work with upholstery type of leather, when it comes to heavy leather you can always use a knife. Of course you can do this on the soft leather too. However, its a lot of work and not easy to get a nice results.

I have a Italian bottom feed with a three motor setup, a full speed knife and small servo for the speed roll. The third motor is for the exhaust fan.

If I use my steel roller on it I can skive heavy weg tan leather with good result, 4 to 5 mm thick (12 oz) is no problem. Like I mention above, I use mine mostly for soft leather. A bottom feed will skive that stuff just fine. It has to be a big skiving job before I change to a steel roller and adjust it for heavy leather. Most of the time it easier to just skive it by hand.

However,If you are going to use it for mostly heavy leather, a top and bottom feed is your best choice.

I see both the choices have a one motor setup, thats means the knife and roller speed is controlled by the same pedal. It must be possible to attach two motors on these skivers too, it is a advantage to have the knife turning at full speed and use a small servo for the feed roller alone. I think it should be possible to do so with any Fortuna style skiving machine, it only a matter of setting it up with the right type of V belts.

To propel the feed roll a small inexpensive home sewing machine servo at 55 to 85 W will do the trick. Then you can use a normal industrial AC motor for the bell knife, let it run on full speed all the time. I do not know if this is possible with this kind of skiving machine, I have seen the Fortuna bottom feed skiver (same as Cobra NP4) set up like this. (My machine is different, it has a inbuilt small servo for the roller, see pic.) If anybody has this style of machine with a two motor setup, please let us know.

About where to buy it.

It was a huge price difference, normally the Consew DCS-S3 costs more than the Cobra NP4. They are sold to $ 1345,- other places. Remember what you pay for, If you buy from Steve at Cobra you will get support. If you are new to skiving machines you will for sure need it.

Good luck.

Tor

[tribo korokan]

I have a Consew Skiving machine DCS-S4 and very frustrated with it.I bought it to skive 2=3 oz. and 3-4 oz. of leather and it always eat up my work. Was trying to make leather wallet with folded edge. I always end up skiving it manually. Saw the fortuna machine just do it so easy on you tube. Is there a trick to make this thing work. attach photo:

[Andrew Chee]

On thing to try is to move the bell knife closer to the presser foot. When you are skiving thin leathers that helps. If there is too much of a gap between the blade and the roller the leather can press down and get eaten up. For thicker leathers, move the blade away so there's more room. See if that helps.

Andrew

[tribo korokan]

I move it close to the presser foot. This is the result and I dont feel that it is eating much of the 2 oz leather like what happened before. I need to do more practice t get it right. And I cant seed to make my bell knife sharp enough. It does seem to be working for me now. Great advice Andrew.

[DDahl]

There is a neat trick to skiving thin leather that I discovered. Go down to your home supply store (home of de pot) and buy a 1" wide roll of Scotch blue delicate surface painters tape (#2080). Now attach a strip to the top edge (finished side) of the leather you want to skive. Trim the ends off close to the end of the leather piece. The tape is very slippery on top and solves and sticking problems nicely. The tape firms up the leather a bit and makes it slide through the skiver like butter. I routinely skive chrome tan leather to a thickness of 0.015" for wallets without the skiver ever eating up the leather. be sure to remove the tape right after you skive it. This with a correctly adjusted skiver (as describe above) will change your world with thin sticky leathers.

Dave

[Trox]

Hi Tribo, I always finishing sharpening the bell knife with the burr removing tool and the grind wheel together; and moving them both away from the knife in the exact same moment. Then I stop the machine to feel with my fingers for burr`s. If you do one side after the other, it will likely form a burr on one side of the knife. The knife must be perfect to skive well, especially on thin delicate leathers. I see that my bell knife has a longer (wider) edge than yours. Perhaps you have to dress your grind stone (with the dresser tool) and then grind a longer edge on your knife (be careful not to overheat). I do not know if that helps or not, but it is important in all other types of skiving; to have the right angle on the skiving knife (I believe it does matter here too).

On difficult thin leather you can use the help of some blue color (painters) masking tape. Place it on the grain side of the leather, to make sure it does not curl up when skiving. The blue color tape is easily removed afterwards.

Adjust your feed wheel to have the same distance from the knife all over its curve/radius. You can use the aids of paper strips when adjusting it. Place them between the feed wheel and knife, bring the wheel closer to the knife and when you pull out the paper strips you will feel the Resistance they give. This way you can adjust the feed wheel distance to be equal all over the knives curve. Then bring the feed wheel back out to the recommended distance from the knife. I use the same distance for all weights of upholstery leather, for thicker leather you can back of the feed wheel spring pressure a bit.

These skiving machines has a step learning curve,but keep practicing and you will get it right.

Good luck

Tor

[tribo korokan]

This is interesting. I am gonna try this one.

[tribo korokan]

The burr remover I presume is the small grinding stick . I notice that I pull hard to get my piece across to get skive.That means my bell knife is not sharp? How many seconds you need to run the grinding wheel to make it sharp.? I did not try the blue tape yet cause I am still learning to sharpen this bell knife . Quite silly . I never thought this is such a big challenge on my part.Thanks again for the advice.

[Ferg]

Two things I notice. You appear to be grinding your knife on a very small portion of the edge. Check the grinding wheel to see if it is level across the grinding face. If not you need to use the "dresser" to make it flat. The grinding wheel should touch the entire angle of the original grind of the bell knife, yours seems to be messed up. Also, your machine has a "stone drive wheel". They can be a problem if not kept very clean. This may not be causing any of your problems now but it can in the future.

The paper method of adjusting the drive wheel to the knife is an easy way to get a nice thin skive but it can create a problem also. You would need a number of different thickness of paper to set different skives.

I take a test piece of leather I am going to use for a project, run it through the skiver. If it is the skive you wish no adjustment of the drive wheel and the top hold down is necessary. The distance from drive wheel to the bell knife should be the thickness of the skived leather you wish when it is finished. Distance between the top hold down and drive wheel should be set to the thickness of the "Un-skived" leather.

It is not unusual to have to fiddle a little bit with the settings for some thin or thick leathers. Gloss finished leathers will feed differently than raw or dull finishes.

Hope this helps a little.

ferg

Edited March 15, 2015 by 50 years leather