Fortuna V50S Skiver grabbing and scalping leather...advice?

[wrightsofman]

I'm hoping one of y'all can give me some advice, because this machine is costing me a fortune in lost leather! 

I'm using it to skive 2-3oz down to 1.5 or so - and I go nice and slow, starting off with it barely gripping the leather at all, slowing lowering the presser foot bit by bit barely removing anything. Then it works really well for a spell, then as I move to a bigger piece or a piece I can't mess up on, it grips it and ruins it. I just can't understand it, and I'm hoping there's a trick I'm missing? 

I have replaced the bell knife, replaced the feed roll with an emory type (it came with a metal toothed roller), and the front tension spring did not provide much tension, so I added some electrical tape around it and that actually helped a lot to decrease the frequency...however, it still happens too frequently. 

Here's an album of the machine and some leather it's ruined!  (https://goo.gl/photos/pPdV57qhxAp1Kha48)

Any ideas? I'd be forever grateful for any advice or tips on more efficiently using one of these machines! 

Cheers!

- Ross

[electrathon]

I have the same skiver.  First off, most people have dull blades.  You said you replaced the bell already though, so maybe. 

It does sound to me like you are using the feed to draw in your leather.  When I adjust mine to do that I will get fubar too.  I pull my leather through, it works well, the feed rollers just assist the feed rate.  Think of it like this.  The feed rollers can't push the leather into the knife or it will wad up into a ball because it is soft and spongy, so you need to hold it firm.

[wrightsofman]

 

I have the same skiver.  First off, most people have dull blades.  You said you replaced the bell already though, so maybe. 

It does sound to me like you are using the feed to draw in your leather.  When I adjust mine to do that I will get fubar too.  I pull my leather por, it works well, the feed rollers just assist the feed rate.  Think of it like this.  The feed rollers can't push the leather into the knife or it will wad up into a ball because it is soft and spongy, so you need to hold it firm.

Thank you so much for the quick response, Electrathon! What exactly is your set up? Like the placement of the presser foot, feed roll, and bell knife? I'm not sure how I could pull it through how I have it now - presser foot just at the edge of the bell knife and feed roll as close as possible to the edge of the bell knife. 

Your method makes complete sense, I just can't seem to visualize how you do it! 

Thanks again!

[electrathon]

Hard to get a good specific picture.  I think the main issue is not having the foot too tight.   The feed wheel needs to slip a little bit, like a car tire on ice. It will push it forwards, but it has a hard time doing it. 

Edited August 22, 2016 by electrathon

[wrightsofman]

On 8/21/2016 at 7:35 PM, electrathon said:

Hard to get a good specific picture.  I think the main issue is not having the foot too tight.   The feed wheel needs to slip a little bit, like a car tire on ice. It will push it forwards, but it has a hard time doing it. 

Well, I spent almost an entire day practicing and trying to figure it all out - and now I see why you were having a hard time describing it! But as soon as I felt it, I knew exactly what you meant. It feels almost wrong, like it's not going to work properly, but it works like a charm! I've been skiving the past few days with no accidents yet (knock on wood!)! Thanks so much for your advice and responses - I really really appreciate it!

 

- Ross

[electrathon]

It is amazing what a good job it does and how fast and easy it is when you get it set up right!  Glad you got it. Time to be Snoopy dance now.

[Gregspitz]

I got my skiver working great after watching the youtube video by Cechaflo where he adjusts the whole thing from scratch. He uses index cards and pieces of paper and it is really easy to follow. SHARP SHARP SHARP BLADE is the key also!

 When in doubt sharpen your blade.  hope that helps

[MADMAX22]

Cechaflo has some awesome videos. If anyone wants to learn about vehicle upholstery watch his videos. i think even JLS would approve of his video style. 

 

[Trox]

It's always important to have a sharp bell knife, after grinding remove any inside burr with the deburring tool. Grind outside edge and use the de burring tool inside simultaneously and stop at the same time, the there will be no burr at any side of the edge. I use the metal roller wheel for thick leather and wegtan. The stone wheel for upholstery type of leather, delicate thin leather. Move the bell knife as far to the left as possible so the edge will be at the top  center of the feed wheel, the roller should be adjusted to follow the radius of the bell knife. I use paper strips to adjust it, this way I can have the exact same distance to the bell knife on both sides of the roller. Then the angel of the skive is set with the presser foot alone. My machine is an Italian Alpha SM, with a constant speed bell knife and an extra little servo motor for the feed roller. On this machine you can feed the material with the feed roller motor. When you have a machine with one motor that control both the roller and bell knife speed is important to use the method that Electrathon describes. The feed roller spring pressure is set differently for different types of leather, more pressure for firmer leather (and wegtan) than for upholstery types. Ones you have setup your machine to the so called zero position (described above) you should only need to adjust the presser foot hight for different thicknesses. If you use one millimeter clearance between the knives and feed roller or two, just measure up some paper strips at the wanted thickness. Place them between the knife and the feed roller and adjust the feed roller until you have the same drag on the paper strips all over the radius of the feed wheel (hold the paper with one hand and adjust the feed wheel with the other) I find this method very usefull, it may save you a lot of leather tests this way. Good luck, Tor