Help a guy out with his new skiving machine!

[jimi]

Hi Yintx, wow that is a lot of scrap in there!! do you have a scrap ejector on the inside of the bell knife?? it should be normally 15 mm from the edge of the knife. Looking at the pictures the settings all look ok to me ( but i am no expert) I usually finish grinding the knife with the emery feed wheel on the inside with just a slight touch. have you checked the spring pressure on the feed wheel? for level cuts or splitting the spring that tilts the roller (the one in your first picture)should be stronger than the spring that dips the whole roller ( the spring at the back with the plate with notches) and vice versa for bevel cuts.

[YinTx]

4 hours ago, keithski122 said:

I've found that with long skiving runs the waste drops out on its own, if doing short runs it stays in grips the wheel and comes back up to the top again.

I've noted that as well.  In the case of the photo, it was all jammed up in there.

4 hours ago, Matt S said:

Yeah scrap buildup around and inside the knife is a bugger. I don't know if it's just cos of the heavy cuts I take or if it's cos I run the knife at top speed but mine seems to clear itself pretty well most of the time. Brian/Rocky Aussie showed how 

Yep, vacuum excavator is next in the works I suppose.

3 hours ago, jimi said:

ave you checked the spring pressure on the feed wheel? for level cuts or splitting the spring that tilts the roller (the one in your first picture)should be stronger than the spring that dips the whole roller ( the spring at the back with the plate with notches) and vice versa for bevel cuts.

I had no idea.  And I don't really know which one is set with more tension that which, so next time I get back to it I'll check for sure.  I'll have to print out these tips and put them with the machine until I get em all memorized!

YinTx

[RockyAussie]

3 hours ago, jimi said:

Hi Yintx, wow that is a lot of scrap in there!! do you have a scrap ejector on the inside of the bell knife?? it should be normally 15 mm from the edge of the knife.

In case you don't have one the scrap ejector @jimi is refering to is a brass bell that fits snugly inside of the bell and helps to prevent some of the leather from staying in there. Do you have it in there? Other than that I think the sharpening on your blade looks like it is to aggressive and should not be showing quite that amount of scratching. If I have taken out some sizeable nicks it would have that appearance but I come back again with a lighter touch pressure on the sharpening stone for a bit than proceed to do the stropping step. What you have there looks like a little saw and it would be easy to get a deflection on the blade particularly upward. There is way too much leather scrap sticking to your feed stone as well and that will need to be brushed off. Another thing I notice is that the guide stop looks very pointed at the front and I would suggest grinding it a bit flatter at the front in order that the leather might not be pulled into it too much and cause a possible bunching that may create bad skiving. Those pointy ones are mostly for shoe upper work and the like where you need top get around extreme curves and such. The fence/guide I mostly use has a flat about 2 1/2" long and if doing long straps you can box it in with a flat magnet as well.Then you can just hold it and let it go. Lastly and after giving it all a clean check, back your bell back a 1/2mm or so and see if it goes any smoother. I do that when doing thicker leathers normally though. Another thing when starting a skive take a little slice off the corner first by holding it 1/2 way in the go around the job in an anticlockwise action so that each new start is not on the thick. That will help not get chop out holes if you are careful when you start the feed each time.

[YinTx]

1 hour ago, RockyAussie said:

In case you don't have one the scrap ejector @jimi is refering to is a brass bell that fits snugly inside of the bell and helps to prevent some of the leather from staying in there. Do you have it in there?

Yes, there is a scrap ejector.  The plugging was clearly operator error, the jicky little bin under it was full and that stuff had no where to go but up.  I removed the bin and let er fall to the floor.  The ejector has a better chance of doing it's job for now...

1 hour ago, RockyAussie said:

I think the sharpening on your blade looks like it is to aggressive and should not be showing quite that amount of scratching.

The first day I had it, the bell was about 1/2" back from the presser foot, and when I moved it forward, the stone beveled an angle that was no where near the cutting edge, so it had to get re-profiled.  I tried to follow up with a really light touch, but it has always had that pattern on the bevel.  I thought maybe that was the way it should be since I've never seen one up close until this one.  I felt it was a bit harsh myself, but kinda didn't know for sure.  Even the light touch with the stone leaves these marks.  Do I need to find a different stone?

 

1 hour ago, RockyAussie said:

too much leather scrap sticking to your feed stone as well

It seems to grab on to whatever leather I am using like glue right away.  I'll get a brass brush and see if it'll clean up.. but if it keeps up past performance, it'll get gummed up fast.  Do I need to replace it with something that won't?

1 hour ago, RockyAussie said:

guide stop looks very pointed

my hunches confirmed again.  I think this thing can be spun around for a less pointed approach, I'll give it a try.

1 hour ago, RockyAussie said:

back your bell back a 1/2mm or so and see if it goes any smoother. I do that when doing thicker leathers normally though. Another thing when starting a skive take a little slice off the corner first by holding it 1/2 way in the go around the job in an anticlockwise action so that each new start is not on the thick. That will help not get chop out holes if you are careful when you start the feed each time.

I'll give this a whirl.  I can't wait to get this thing dialed in and my skill up on it, I think it'll open a whole new world for me...

YinTx

[RockyAussie]

1 hour ago, YinTx said:

Yes, there is a scrap ejector.  The plugging was clearly operator error, the jicky little bin under it was full and that stuff had no where to go but up.  I removed the bin and let er fall to the floor.  The ejector has a better chance of doing it's job for now...

The first day I had it, the bell was about 1/2" back from the presser foot, and when I moved it forward, the stone beveled an angle that was no where near the cutting edge, so it had to get re-profiled.  I tried to follow up with a really light touch, but it has always had that pattern on the bevel.  I thought maybe that was the way it should be since I've never seen one up close until this one.  I felt it was a bit harsh myself, but kinda didn't know for sure.  Even the light touch with the stone leaves these marks.  Do I need to find a different stone? A finer stone is often better https://campbell-randall.com/product/fav-400ro1-pink-emery-grindstone-non-porous-175-mm-bore-italy

I use a similar same brand one though it is 400SB not 400R01

It seems to grab on to whatever leather I am using like glue right away.  I'll get a brass brush and see if it'll clean up.. but if it keeps up past performance, it'll get gummed up fast.  Do I need to replace it with something that won't?I think so, a medium stone is best and I think yours may be coarse. See if you can check on that first. All that leather sticking is normally a sign that the leather is not feeding through and you are spinning your wheels so to speak. A rough wheel would give more grip but generally a better answer is a sharper blade and  maybe  better settings. If it is from 2mm+ thick leather or hard leather than a double skive is sometimes the answer. Ist skive at about 1/2 the desired thickness. Sometimes its just the bell needs to be a bit further back. https://campbell-randall.com/product/fav-801-2-50mm-emery-feeding-roller-2-medium-grit-italy

my hunches confirmed again.  I think this thing can be spun around for a less pointed approach, I'll give it a try. OR - https://campbell-randall.com/product/fav-1244-straight-edge-guide-p1657l

I'll give this a whirl.  I can't wait to get this thing dialed in and my skill up on it, I think it'll open a whole new world for me... OR -

YinTx

 

[alexitbe]

Could there be a burr left after grinding which just needs removing?

Alex

[YinTx]

Thanks @RockyAussie for more pointers, I've bookmarked the goods.

However, perhaps the plot thickens.  Here is what I came across this evening.  I noted that the feedroller was constantly pulling up leather fuzz and feeding it to the bell, as I was running it with no leather.  So I peered up underneath, and lo, jammed up under the feedroller was this nice little ball of skived leather.  I worked it out, and it promptly trapped another.  I am assuming this is not normal behavior.  How do I remedy it?  Do I need to just scrap this scraper?

 

 

19 hours ago, alexitbe said:

Could there be a burr left after grinding which just needs removing?

Alex

Entirely possible, I've tried to make sure there isn't one, but this bell thing is new to me and I'm learnin...

 

I also have proof the good leather sensor is functional on this unit.  Ran a lot of scrap in there, it skived beautifully, went to skive the good stuff, and viola, shredded.  Picked up a piece of scrap without changing a thing, skived it perfectly.  Sensor functioning.

YinTx

[RockyAussie]

1 hour ago, YinTx said:

 I worked it out, and it promptly trapped another.  I am assuming this is not normal behavior.  How do I remedy it?  Do I need to just scrap this scraper?

Oh mate i am feeling the pain from here. I dont have any of that scraper stuff on mine and I suppose that is because of the suction equipment on them. That dish shaped ejector thing at the back is about 15mm or less in and that keeps the bigger strips from going around and around. From what I can make out in your photos the scraper is a plastic wear style thing and should be adjustable to run right up against the feed stone. If it is held against the feed stone with a spring pressure it may not be adjustable in which case a smoother feed stone may be an answer.Almost any gap will work to trap the thin skived pieces so if it is adjustable I would give it a try right up lightly touching myself. Hopefully others here hopefully may have experience with this arrangement. The other thing is that if you bring the dish ejector forward you will need to bring back as well that other metal scraper as well and that should work to eject the strips better. You probably have already seen this post but in case you want to see it again this is it -

You know if I were making that style of ejector wiper thingy I would have used a shaped out bristle brush to really scrape that fluff out of the grit.

[RockyAussie]

Just another thought ....I think that plastic wiper thing will be spring pressured and with the plastic block being somewhat thick it may act as a funnel and be excellent at trapping the leather until it wears down to where there is no edge left and it is firm against the feed stone. Try having it run with the feed stone engaged until you can see no ledge. What have you got to lose?

[alexitbe]

I don't know anything about this machine, but is the scraper at the correct position and angle to the knife?  Is it possible to vary these?  I would put the scraper either just after the leather has been cut by the knife or at 6 pm on the bell knife after gravity has collected all the leather from the cut... I guess there will be an optimum angle too...

 

Have you thought of replacing the scraper with something that doesn't let things gather under it.... say something like an angled rod (like a finger stuck inside bell knife) that presses into the bell knife... It would remove the big pieces of leather, which presumable take the littler pieces with it...

 

alex