Advice for thickness of leather for bellows

[Rod Pearce]

I am having my first go at making a bellows for an Anglo concertina. I have tried to repair leaks in the existing one several times but just keep finding more. It seems too far gone.

 

I have gathered most of the materials, cut the card and built a jig for the assembly. The only thing I am short of at the moment is the leather, and am planning to use black goatskin from Pittards. I have lined up a 0.9mm skin.

 

I have been trying to get an idea of the thickness of leather needed for the various leather components ( gusset, top run, end run, valleys) but all I can find is a lot of references to the edges needing to be skived to 0.01mm.

 

Can anyone advise what the thickness of the body leather for each of the components  should be?

 

Thanks

Rod

[alex_holden]

It depends on various factors, but I'm generally aiming for something like 0.6-0.7mm, skived down to almost nothing at the edges. Don't bother trying to measure the edge thickness, the point is simply to get it so thin that when you stick it down the join is practically invisible.

[Rod Pearce]

Thanks Alex.

 

Can I assume this applies to all the leather components?

 

Rod

[alex_holden]

Pretty much, yes. That should be a reasonable starting point anyway. Bellows are a complicated subject and I haven't made two sets exactly the same way, but it wouldn't be too helpful if I gave the true answer, "thick enough but not too thick".

[Rod Pearce]

OK, I'll work with that when the leather arrives.

 

Thanks for your help.

 

Rod

[david robertson]

I think you may find that 0.9mm is a bit heavy, particularly for the gussets. Personally, I use 0.5mm, which, allowing for natural variation, is pretty close to Alex's recommendation.

[alex_holden]

5 minutes ago, david robertson said:

I think you may find that 0.9mm is a bit heavy, particularly for the gussets. Personally, I use 0.5mm, which, allowing for natural variation, is pretty close to Alex's recommendation.

I think David’s right, my previous numbers were a bit on the high side. I’m assembling a new set of bellows right now and I made the gussets for it 0.5mm thick. 

[Rod Pearce]

David, Alex

Happy New Year to you both, and thank you for your replies.

 

The leather on order is 0.9 mm as it was the thinner of two skins on the website, I realised this was probably too thick, but wasn't sure what I should be aiming for.

 

I will need to practice my skiving skills, by the sound of it! Should keep me busy for a while.

 

In the meantime I can start assembling the card (as per the Tedrow method) as the gummed tape has just arrived.

 

Regards

Rod

[Notemaker]

On 1/6/2020 at 6:35 AM, Rod Pearce said:

 skiving skills,

 

Regards

Rod

Mentioning skiving, which kind of tool is best?

 

https://www.amazon.com/YaeTek-Leather-Machine-Splitter-Skiving/dp/B07BJX9XC3/ref=sr_1_64?keywords=leather+skiving+tool&qid=1578689405&sr=8-64

Is this overkill ?

 

Or would this be a better solution?

 

https://www.amazon.com/MIUSIE-Leather-Comfortable-Convenient-Thinning/dp/B07FSFZL1Y/ref=pd_cp_201_2/140-2362937-5734634?_encoding=UTF8&pd_rd_i=B07FSFZL1Y&pd_rd_r=805959ff-19fe-4d68-88f6-a96c6169fee6&pd_rd_w=lJoAO&pd_rd_wg=H0atg&pf_rd_p=d534d65f-a237-49e4-9070-a58a3a6b8ba4&pf_rd_r=PBAEMH2NVZMHECWXDX35&psc=1&refRID=PBAEMH2NVZMHECWXDX35

 

Thank you.

 

[W3DW]

Asking leatherworkers what skiving tool is best is like asking this forum which concertina is best! I use a varient of the second tool you posted, using single edge razor blades, but a scalpel also works for me as well. 

 

I've had no luck with big machines with drive mechanisms except when working with saddle leather, but I just KNOW there's somebody out there who can skive gussets masterfully with one. 

 

Skifes are like concertinas - keep practicing! 

 

Daniel 

[Mike Hulme]

 

https://www.amazon.com/YaeTek-Leather-Machine-Splitter-Skiving/dp/B07BJX9XC3/ref=sr_1_64?keywords=leather+skiving+tool&qid=1578689405&sr=8-64

 

This is the Chinese version of the classic German Scharf-Fix machine which has been around for years - at about 5 times the price of the Chinese offering!

I bought one last year and, with careful setting up will do the job well.  The safety razor blades they come with are rubbish however, and you would need to source some high quality blades (Personna Platinum for example) and only skive two to three feet of leather with each edge before changing edges/blades.

 

Mike

[alex_holden]

I used a Schärffix 2000 (bought before the Chinese started knocking it off) for all my bellows until the most recent set. The Schärffix does work OK and some leatherworkers seem to love them, but I always found the disposable razor blades very frustrating. A good blade (I'm using the Personna ones) cuts almost effortlessly when it's fresh out of the packet. Then it starts going dull within a few inches of skiving, and as it gets duller the force needed to pull the leather through the machine increases. As the force increases, the edge of the blade and the top arm of the machine start to deflect, altering the depth of cut. You also end up stretching the leather sometimes. I found I was constantly having to measure parts and tweak the depth setting. Often something would go wrong and the blade would dig in and ruin the piece I was skiving (I got better at avoiding that with practice). Every few feet you need to stop and change the blade, which will cut to a different depth than the old dull one, so you have to do some test cuts and adjustments before you can get back to skiving real parts. After skiving all the parts for a set of bellows I would have a small pile of worn out blades to dispose of.

 

I recently upgraded to an old industrial Fortuna bell skiver machine. It is more complicated to set up than a Schärffix and has its own quirks and issues to deal with, but for me the rotating bell knife with its built in sharpening system is a massive improvement over disposable razor blades.

 

6 hours ago, W3DW said:

I've had no luck with big machines with drive mechanisms except when working with saddle leather, but I just KNOW there's somebody out there who can skive gussets masterfully with one. 

 

I wouldn't claim to be 'masterful' yet, but I did manage to produce an acceptable set of parts with it:

 

[SteveS]

11 hours ago, alex_holden said:

I used a Schärffix 2000 (bought before the Chinese started knocking it off) for all my bellows until the most recent set. The Schärffix does work OK and some leatherworkers seem to love them, but I always found the disposable razor blades very frustrating. A good blade (I'm using the Personna ones) cuts almost effortlessly when it's fresh out of the packet. Then it starts going dull within a few inches of skiving, and as it gets duller the force needed to pull the leather through the machine increases. As the force increases, the edge of the blade and the top arm of the machine start to deflect, altering the depth of cut. You also end up stretching the leather sometimes. I found I was constantly having to measure parts and tweak the depth setting. Often something would go wrong and the blade would dig in and ruin the piece I was skiving (I got better at avoiding that with practice). Every few feet you need to stop and change the blade, which will cut to a different depth than the old dull one, so you have to do some test cuts and adjustments before you can get back to skiving real parts. After skiving all the parts for a set of bellows I would have a small pile of worn out blades to dispose of.

 

Alex - I've had a similar experience - and it takes forever to skive all the leather for a set of bellows.

More recently I use the Schärfix 2000 to reduce the edges somewhat, then use a round blade scalpel to get the edges nice and thin.

[Rod Pearce]

As I don't own anything like a Scharf-fix, I have been exploring ways to get a reasonable skive at a reasonable cost.

 

It suddenly occurred to me that if I could fashion something that would hold a sharp blade at the required depth from a hard surface while holding it steady and pull the leather through it, I may get a reasonable skive.. This is what I came up with, and it seems to work. It cost me nothing as I had all the 'components' to hand.

 

Basically, I put two used utility knife blades about an inch apart on a sheet of melamine faced chipboard, put a new blade into an old paint scraper, sat the scraper on the two  blades, fed the leather to be skived between the three and pulled slowly while keeping a tight grip on the scraper.. The result was much better that anything else I have so far tried, but for it to be a workable solution I will need to find a way to hold the used bladed in place. I am able to go vary my speed to suit the behaviour of the leather

 

The utility knife blades are just about 0.5mm, giving a 0.5mm skive. I also have another craft knife whose spare blades are about 0.4mm.

 

I'll keep refining the idea until I come up with a reliable, repeatable solution

[wunks]

Would it work smoother with the cutting blade set at an angle instead of at right angles to the work piece?

[Rod Pearce]

I can try it. The scraper can be moved to any angle as it isn't fixed

[Rod Pearce]

I have got my leather strips down to 0.5 mm (with some help )but am struggling with the edges. If I use a knife or blade I am struggling to keep the edge straight. I am assuming they need to be as straight as possible.

 

Any advice?

[paaudio]

I recently bought a few trial pieces from here......

Thank you for your enquiry. We manufacture the leather bindings mentioned but in a softee hide leather not goatskin.

If you would like to let me know the sizes required I can advise the cost. We either split thin at .2mm across the whole width or centre split to .6/.7mm with both edges bevelled.

Please send your address and I can send samples.

I look forward to your reply.

Kind Regards

 

Lynda

 

Lynda Cornish

C. A. CORNISH  |  21 High Street  |  STREET  |  Somerset  |  BA16 0EF

Tel: +44 (0)1458 442746  |  Fax: +44 (0)1458 443850

sales@cacornish.co.uk  |  www.cacornish.co.uk