TomE

That’s a nice piece of work! Wish I could weld like that.

Nigel Armitage has a video on sharpening the blade of an Osborne #84 splitter. He swings the blade around 180 deg and leaves it clamped to the base of the splitter. That's what I do for my Taiwanese Tandy Pro splitter. Edited to add: That is the video posted above by @jcuk. Guess CS Osborne likes his method.

You could try heating the crease and using it on dry leather. When the temperature is right the crease will glide with less resistance than at room temp. Too hot and it burns the grain of the leather. I use an alcohol lamp to heat the crease. You will feel the heat coming up the shank of the tool when it's about the right temp. Creasers come in many sizes and shapes. Some are easier to use than others. You can reshape them to change the width of the crease line. The Osborne creasers (like all Osborne tools?) need a bit of smoothing and polishing to work really well. Same for the Vergez-Blanchard screw crease. I always crease after finishing the edges of straps - beveling, dyeing, burnishing - then creasing. I repeat the creasing after oiling and before applying conditioner.

What type of creaser are you using - fixed or screw crease? What size is it (how close is the crease to the edge)? Is the edge beveled and burnished before creasing? A picture would help. Do you heat the crease or case the leather before creasing? Don't do both. I find that applying light pressure to establish the crease line before bearing down will give me more consistent results. The creaser works best on leather with a firm, even temper. Harness leather is especially nice because of the waxes that lubricate the crease.

The diagram is easy to see but it's not easy to calculate stitch spacing from the angles shown. I think it's easier to calculate the inner and outer circumferences then convert the spacing of the outer piece to that for the inner piece as the ratio of circumferences. My point is you will end up with something like 6 and 5.5 stitches per inch for the 2 pieces and I don't know how to accurately mark 2 spacings with a small difference. Won't have to do this with an awl. Skipping a hole doesn't fix the spacing.

Not East Coast but Leather Machine Co has a blade sharpening service for the Class 14 splitter. The blades are hollow ground. I've seen comments stating that they also sharpen blades for other machines. I would search for a local service that sharpens wood working tools.

The math is analogous to the question in the post below - how to calculate the allowance for padding a collar - with the additional consideration of hole spacing that is proportional to the 2 circumferences. That said, it will be a small difference and difficult to accurately mark on the 2 pieces. I'd use an awl.

That's for a big dog! Very pretty. I like the color scheme.

The Stohlmans mention in their Encyclopedia of Saddle Making that they used lots of neatsfoot compound to good effect, but they acknowledge that pure neatsfoot oil is a better product without explanation. Anybody have an explanation? Waterproofing products typically contain silicon oils that I believe are also petroleum based. I use Saddle Oil, Golden Mink Oil, and Sno Seal on work boots. Pure neatsfoot oil on tack.

Beeswax applied with heat and slicking, or a waxy conditioner like Fiebings Aussie.

A glass slicker is useful for burnishing the flesh slide with wax, glue, etc. Loose fibers on the back side might indicate a loose structure overall that makes for a weak, stretchy strap. I mostly use bridle leather with a moss-back (pasted back). A flexible, pasted back can be created with this product that I use if I split the back off bridle leather. It is sold in quarts and gallons. https://campbell-randall.com/product/sup-bt639-g-leather-finish-for-sealing-flesh-side-moss-back-suede-1-gal

That’s beautiful, @Sheilajeanne! Love the design and the colors.

Polish has waxes and leaves a shiny finish that is somewhat water repellent. Mostly a surface treatment. Leather conditioner creams, balms, etc. aim to add some moisture to the fibers. They soak into the leather and typically leave a satin finish. The choice of finishes depends on the use of the item and your preferences.

Learning to sharpen the tools is part of learning to use them. Another reason to start with modestly priced tools. I have enjoyed using CS Osborne tools once I learned how to sharpen them. Like most tools, they need some sharpening when new to work correctly. Stohlman’s book on Leather Tools has some good tips. This cheap Japanese style skiving knife works surprisingly well once it is sharp. https://a.co/d/cuO9tG1

Thanks, @jcuk. From the pictures the temper looks similar to the Beiler's apron split that I purchased. Softer than the apron I am using for a pattern. The apron is 6/7 oz (~2.5 mm) and the Beiler's apron split is 7/8 oz (3 mm). Plenty heavy IMO but it will lay differently when working under the horse. The client/friend will stop by tomorrow to check out the leather for his apron. I might order the firm pearl split from Hide House and give him a choice. He's highly skilled and kind enough to shoe a couple of horses for us (I trim the others) so I want to keep him happy. I might make mayself an apron with the other split.