Hello,
I recently got a Bell Skiving Machine but I'm having some issues...
1. skiving result isn't consistent : I have sharpen the bell skiver blade and when I test out with thicker leather(from 2.0 mm to 07), it works fine.
Q: Does speed makes skiving more accurate? If so, why? I think if the blade is sharp, the speed shouldn't matter...and I tend to do skiving in slow speed... it is kinda scary for me... but, I would like hear from you guys who's been using skiving machine for a long time.
2. It shreds some part of goat skin: I've got this goat skins a couple of years ago from Buyleatheronline.com, but one is in excellent condition, but the other one is kinda much more wrinkly and super stretch....it is very apparent this one has poor quality than the other. I've been trying to skive this from 2.00mm to 0.8mm. Initially I was successful, but it started to have result like in the pictures....
Q: is this also a sharpness of bell skive blade issue or leather issue? Considering the fact that there was successful tries and result, stretch skin isn't much of factor that having a poor quality of skiving job, but again, I am so new to this, not sure about it.
3. Stone feeder seem like it is pulling thin leather in between crevice... my leather got pulled in between the blade and rear bell cover... It seemed thick leather works better than soft hides...
Q: Is it a same issue? Blade sharpness issue? Or, this stone feeder is too rough? Is rubber feeder a better alternative? If so, then why?
In all, the skiving machine works. but I need that 8% of fine tuning and I think I am in a good place to ask my questions. ;) I would appreciate if you could throw your 'know-how' senses on this post!
Thank you in advance.
Young
Any piece of advice I will give bellow presumes that your machine is in good working condition which means you have a sharp blade, well adjusted roller, a concentric to the blade, polished and correctly adjusted presser foot.
I will also presume that the real subject of the discussion is actually splitting rather than skiving leather.
First, a good rule of thumb is to never try splitting down leather in thick layers at once. By thick layers I mean more than 0.5 mm. If you need thinning, lets say 2mm down to 0.5mm, the best approach is to have successive splits until you reach the desired thickness.
Also, keep in mind that soft leathers under 1mm are always prone of raising problems even on machines equipped with suction. And this is especially valid when thinning down to under 0.6mm in thickness. Because any bigger bits of residue that sticks to the roller, when turning on the roller, will increase the pressure on the skived piece between the knife and the roller leading to 'bites' in the chorium up to the grain, resulting many times in holes to the surface of your leather piece.
Suction, though, tends to reduce the possibility of these things happening.
The roller speed is always a good idea to be at the lower end because it leaves more time to the roller to dispose any residues that would affect the splitting process. You may also consider adding a separate servomotor to your feed roller if you find the need of a better speed control.
Any other piece of advise given to you in the comments section is valid and should be taken into consideration.
to get a consistent thickness when skiving you need the same consistency in the material (stiffness)
it's easier to skive veg tan leather because it's stiffer and more firm than say a soft goat hide. would it be easier to skive a piece of poster board or a soft sponge, the soft materials will always bunch up on you and cause headaches
happy skiving
Ok, let's see if I can help here.
1) Speed has never mattered to me. Slow saves time by avoiding rushed mistakes. Consider speeding up when you have more experience and/or using leathers that skive easily.
2) Quality plays a HUGE role. I do notice that some of your skives are so thin that I can see the grain texture from the flesh side. This is exceptionally thin and not really usable outside of decoration or artwork perhaps. This does tell me your blade is sharp however.
4) I prefer a rubber feed roll. I always (carefully!) feed the roller into the blade (slowly rotating the micro height adjustment knob) so that the bell knife trims off any high spots on the rubber roller. This makes a 100% copy of the bell knife to the roller. You can't do this on a stone.
May I also suggest a 0.2-0.3mm gap between the presser foot and the blade if you are mostly skiving and splitting thin skins. A 0.5mm gap is general purpose and also works better to relieve the pressure from skiving thicker leathers and firmer leathers.