Tool Optical Comparators

[oldtymers.kingston@gmail.]

Anyone out there that can help me decipher optical comparators. I make very small parts i.e. escape wheel for a platform escapement. O.D of wheel 0.340 with 15 teeth. I have a tool makers microscope but struggle with the process of making cutters to duplicate the teeth. I'm told an optical comparator ids the answer but when I look on line for used the information is confusing. Horizontal vertical. Machine size and what to avoid.

 

[kstrauss]

I can't help with your comparator question but your assortment of machines (similar to mine) piqued my interest. Where are you located? And welcome to the group as a new member!

 

[Susquatch]

Welcome from farm country South of Chatham in Ontario. I make and fix MUCH BIGGER stuff.

So I can't help either. But some of our members have watch making skills. I'm sure they can help. If they don't reply, you could browse the forum and reach out to them.

 

[oldtymers.kingston@gmail.]

I can't help with your comparator question but your assortment of machines (similar to mine) piqued my interest. Where are you located? And welcome to the group as a new member!

I would be in Kingston On. Kind of a backwater when your looking for machinist stuff. Most of our industrial suppliers don't stock anything anymore. Thanks
Tim

 

[kstrauss]

You think that Kingston is a backwater? I'm in Cobourg (about 100km east of Toronto) and there isn't an industrial supplier around with or without stock. Have you visited the toy shop in Perth (https://cardontools.ca/)?

I'm only 2 miles from the highway so drop in you ever head west.

 

[gerritv]

I have a vertical one, Nippon Kogaku 6 (aka Nikon). A friend had a horizontal Jones-Lamson horizontal but replaced it with a vertical one (same as mine)
My opinion, the horizontal ones are best suited to larger or longer parts. The vertical ones let you place items directly on the glass, or in a holder or across v-blocks. I 3D printed 2 v-blocks, copies of the Mitutoyo 172-378 unaffordable ones.
The Nikon 6 comes with 1 or a turret with 3 lenses. Get the 3 lens turret. 10x,20x,50x seem adequate, the 100x needs a LOT of light. You can do profile/shadowgraph views and with the right mirrors or splt optics surface viewing (needs a lot of light).
I converted mine to LED since I had no spare bulbs, works much better with a lot less heat.

You measure direclly on the screen (carefully or with some mylar) to protect the glass. Divide by magnification. Or make a drawing, print on tracing paper and overlay over your part. Some screens rotate (mine doesn't, instead the stage rotates) to measure angles. Or buy inepensive mylar overlays from eBay with various grids, circles, angles etc.

Pic is of a M3 button head, I think it is 20x

Bought it for the princely sum of CA$150 during height of Covid. one sold last year for about the same, it was shipped for $200 as LTL freight on a skid.

gerrit

 

[gerritv]

Specifically for your use case, you can mount the cutter on an arbor across 1 or 2 vblocks to see the profile, and with some further jigging set the wheel against it to see if the profiles match. It takes a bit of practice to get the focus correct without false shadows/edges but once you know what to look for it is quick.
I often use mine to verify threads of unknown parameters, or when threaded item won't fit a nut. E.g AG60 inserts claim to cut down to 48tpi but due to the tip width are in fact incapable of doing so. Hard to see at 0.3mm pitch

gerrit