Actually unless it's a real old(I'm talking 1850-1870 era) most improvements you make will increase the value (as long as they are for thre better)
so as Darren said keep the old parts incase you want to put them back on & get it setup the way you want.I feel things like a DC Servi improve the value as it'll be more user friendly machine to operate.
HTH,
Bob (Live from Sheridan,WY)
The best way to find out is to take your leather your going to use ( some types of leather sew different than others)& try it on the 205 first,it's the better one for leather,it will be sewing at it's max so you might even have to lube the thread to help it sew.
Bob
Your stopping it in the wrong spot,try stopping right after the needle picks up the thread,let the needle come out of the material & then pull alittle slack thread & pull out the material you've sewn.
Bob
Yes,this sounds like a good buy.They take the 138 w/o any problems & you'll also like the larger bobbin.The feet from your 111w wil;l fit on it too.
Also when replacing the bobbin you don't have to pull it up through the needle plate like on the 111w,just leave approx 1" tail of thread put it in & start sewing.
Bob
It's been a while since I ran one ,but I think it'll handle chap weight material ok using #69 or 92 thread.
We probably have the needle but on a machine this old have found out that alot of times people change them for something different & would like to see an old one if you have an extra to mail us.
Bob
A machine w/o a bobbin makes a chainstitch that will have loops on th bottom of the stitch that looks like the under side of a potato bag,very unsightly in leather.
There are machine like Singer 300w that make a chainstitch & used in tarp & canvas & even some auto upholstery.
Bob
You might want to take the needle plate off & see how close the hook is to it,it might be hitting do this to much & you'll be needing a new hook,you might try adjusting the hook guard to just touch the needle.
Bob
Well this machine is for sewing thin material like clothing,it might sew thin leather like pocketbooks,wallets with # 69 thread maybe up to 1/4" thick.
Bob
Nice machines you have there.That one look similar to this Singer 98-2 I have,which was made for rebooting car tires (back in 1915)
I think it would sew leather easily to 1/2"
Bob
Ok,take the needle plate off,turn the machine around so the needlebar is all the way down & turn the machine in the direction it runs & let the needlebar rise up 3.6mm & the point of should be @ the needle.Let me know what happens.
Bob
Here's a pic of the pad that was supposed to hold the oil.I've marked the 3-spots that you should oil.If you fill this well up you have a big mess,so if you oil these 3-spots often the excess will run down in the well anyways.
Bob