I bought a band-knife splitter

[Danne]

12 hours ago, Matt S said:

Tack, Danne I'm glad you're enjoying it. I'm sorry it's such a strung-out saga but I'm spending the odd hour on this machine whenever I can around my other commitments. Right now I don't have the time or resources to properly rebuild this machine (and I don't think it really needs it) so regrinding the the gibs is something I'm avoiding if at all possible and for now.

Thanks fella. The top blade on mine is only held in place with two countersunk hex-socket screws. I tightened them according to the manual, which was pleasantly simple. No torque ratings, no fannying about, just tighten but not too much that the plate stops rocking on its springs. Then tighten the locking eccentrics so the guide stops rocking and then tighten their locking screws. Those are the sorts of instructions even I can follow. I checked and I can't get a piece of copy paper between the knife and either guide but can turn the knife over by hand. Excellent engineering.

I've solved the mysteries of the auto sharpening feature. In case someone comes across this thread in the future is also trying to fathom it out, the timer appears to be an interval timer that sends out a ~0.5sec 220v pulse between each interval. I.e. if you set it at 10 minutes it'll close the contacts for half a second, then off for 10 minutes, close the contacts for 0.5sec again, ad infinitum. A simple thing to replicate using off-the-shelf parts if you're so inclined.

The timer does not output to a clutch or an electronic control for the grinding motor as I suspected but to a solenoid directly behind the knife advance wheel. For each pulse it receives it advances the knife one notch. I presume that this brings the knife edge heavily into contact with the emery wheels and the edge is ground back by the same amount. I've hooked it up to a temporary toggle switch inside the electrical panel but I doubt I'll get into the habit of using it for all the reasons Rocky said.

This was about the limit of my knowledge of band-knife machines too until I bought this one, though I don't have nearly your engineering skill. I was fortunate enough to be in the right place at the right time and had to jump on the chance, though I spent the money I had budgeted for some cutting dies I sorely needed (and still need). Apart from the labour (which was mostly days off and evenings) I've spent about 5-6% the cost of a new machine on this one.

Bell-knife skivers are real handy machines. You can do some small splitting with one (and I do... or did...) but I've never got it setup so I'm happy with the finish if I have to do multiple passes. The largest roller-foot I have is 40mm and it has sharp edges so if the leather's any wider than that I end up with tram lines. The error is probably between the seat and the machine in my case, but that's my experience.

I've got a few PDF manuals I can send along if you're curious but I don't think there's many/any exploded diagrams. Mostly line drawings of sub-assemblies if their function is not immediately clear.

8

"I've spent about 5-6% the cost of a new machine on this one." Wow, sounds like you made a really good deal. 

Regarding splitting with a skiving machine. As I said I have no experience there either. But I have seen people split leather with good results. (Softer leather like chevre sully or alligator and such.) I have seen different types of presser feet, some have slightly rounded edges. 

I would really appreciate the pdf-manuals you have. I really hope you get this machine into full working condition.

 

[Matt S]

5 hours ago, Danne said:

"I've spent about 5-6% the cost of a new machine on this one." Wow, sounds like you made a really good deal. 

Regarding splitting with a skiving machine. As I said I have no experience there either. But I have seen people split leather with good results. (Softer leather like chevre sully or alligator and such.) I have seen different types of presser feet, some have slightly rounded edges. 

I would really appreciate the pdf-manuals you have. I really hope you get this machine into full working condition.

Like I say I couldn't turn the opportunity down. It's not been a free ride -- I've probably put nearly 100 hours' work in over the past few months so if I were turning down paid work the price comes near to what dealers charge for a refurbished machine like this. However I've learned a lot about how this machine works and I've enjoyed myself hugely. The latest Camoga machines are half the weight and I suspect much quieter and more user friendly. They are, however, eye-wateringly expensive.

Splitting with a skiver is certainly possible. Mine doesn't take new-style feet without more adjustment than I'd like and I want to keep the sharp corners on my roller foot because it gives excellent step skives.

Re. the manuals I'll send you a PM.

[Danne]

21 minutes ago, Matt S said:

 Like I say I couldn't turn the opportunity down. It's not been a free ride -- I've probably put nearly 100 hours' work in over the past few months so if I were turning down paid work the price comes near to what dealers charge for a refurbished machine like this. However I've learned a lot about how this machine works and I've enjoyed myself hugely. The latest Camoga machines are half the weight and I suspect much quieter and more user friendly. They are, however, eye-wateringly expensive.

Splitting with a skiver is certainly possible. Mine doesn't take new-style feet without more adjustment than I'd like and I want to keep the sharp corners on my roller foot because it gives excellent step skives.

Re. the manuals I'll send you a PM.

If you bought a refurbished machine, it would be nice at first, but soon you would probably discover you need to learn how everything works, all those small important adjustments you need to do.

A new Camoga like the Camoga Compact have automatic knife trend setting. Easy to replace knife, and switch between roll/bar. But I’m sure the build quality is not like the old machines. 

[Matt S]

On 3/10/2019 at 9:23 PM, Danne said:

If you bought a refurbished machine, it would be nice at first, but soon you would probably discover you need to learn how everything works, all those small important adjustments you need to do.

A new Camoga like the Camoga Compact have automatic knife trend setting. Easy to replace knife, and switch between roll/bar. But I’m sure the build quality is not like the old machines. 

A new one would be better for sure, probably in every regard except for price. When I priced the Camoga Compact late last year it was in the region of a new hatchback. Dealer refurbished similar machines to mine are in the region of a 10-year-old hatchback. Mine cost less than a month's minimum wage. I can tolerate a lot of manual tracking/trend adjustment for that price difference!  And even mine is pretty simple to switch between bar and roll -- two screws and no adjustments necessary.

It's probably no surprise but I couldn't wait to try a split and yes I've put a few offcuts through for testing. Mostly it has highlighted specific areas where I need to adjust or clean the machine. Long, boring story short I've been knocking them down in turn. Not many photos as there's not a great deal of point in a string of "here's some oily rust and here it is gone" photos. Knife was pretty sharp but a few grinds (once the emery wheels were adjusted) increased the smoothness of the cut.

The biggest issues were around the depth of split. In just a couple inches of distance the knife was plunging up and down. Variance of maybe +- 0.5mm which is well above the acceptable range. After getting the knife exactly at the zero-setting (its optimal distance from the feed roll) things improved a little. Figuring that the feed roll assembly isn't moving up and down as smoothly as if it were perfectly clean I increased the presser tension and my splits started being longitudinally consistent. Presser tension is a little higher than I would expect from the manual but still within the bounds of normality.

Now I moved to calibrating the thickness scale. As with many such things I know that I can't just rely on what's on the dial -- I will always have to check the split piece with the gauge for accuracy. However having the scales as close as possible to the expected output would be pretty handy -- it'll let me get to it with far fewer trials.

There's a coarse readout on the RHS of the machine in whole millimeters. The scale can be slipped so that was easily adjusted but the fine thickness readout (in tenths of millimeter) is on the thickness adjuster itself. I had to strip the presser assembly fairly extensively in order to fix an issue with the drive and I presume that I got them slightly out of goose when I did that, though I don't know if they were accurate when I bought the machine. The manual did not describe how it's supposed to be done so I split a piece of leather, measured its thickness, then fettled the readouts until they tallied.

Not quite knowing what I was doing I made an educated stab in the twilight and loosened these two nuts either side of the adjuster. This took a bit of pen oil and elbow grease.

 

This allowed the adjuster to be rotated in reference to the two axles on which it runs, so it reads the same as what the leather has just split to. (This was a three-handed job.) Then tighten up the nuts. (This was a 5-handed job.) Notice that there are two fine readouts -- once for when the presser bar is fitted (to the left of the wheel) and one for when the presser roll is fitted (to the right of the wheel). I have mine fitted with the feed roll.

 

Then set for a specific thickness (say 2.0mm) and test.

That'll do I reckon.

[chrisash]

Tut Tut , That "that will do attitude" matt, your old headmaster would shake his head 

[bermudahwin]

2 hours ago, chrisash said:

Tut Tut , That "that will do attitude" matt, your old headmaster would shake his head 

I'm sure he's a lost cause, unless we can help him back, Chris

H

(and no I am not being too rude... he called me neolithic! and anyway, he is VERY helpful, and nice to chat with)

[Matt S]

6 hours ago, chrisash said:

Tut Tut , That "that will do attitude" matt, your old headmaster would shake his head 

"Matt sets himself consistently low standards..."

3 hours ago, hwinbermuda said:

I'm sure he's a lost cause, unless we can help him back, Chris

H

(and no I am not being too rude... he called me neolithic! and anyway, he is VERY helpful, and nice to chat with)

Blimey Harry, I don't know who you've got me confused with but I want to buy him a pint.

[bermudahwin]

Neolithic old folk often make mistakes like that