Member postings for Steve Crow

Camera battery just died! Will get photos later.

This site quotes 2.25 x Mod for involute gears.

Aren't Thornton cutters cycloidal? I'm using involute.

I'll try to take a photo.

Ivan Law quotes a DoC of 0.65mm for Mod 0.3. Other sources told me 0.675mm. I went for 0.67mm.

Hi Martin, with my project, it's going to be mainly pinions driving wheels for a calendar and a lunar train.

I am wondering if my tooth profile is ok.

I put my wheels on the scanner and set the dpi to 1200 and got quite good results. Here are 4 different wheels, 73, 64, 60 and 48. All but the 48 crossings are part filed to shape.

Can anyone see any fault with the profile?

Steve

Thank you for all the replies.

I realise that it is a transfer tool rather than a measurement tool and that is how I intend to use it.

I was just interested in what the best distance actually was. I'm glad I did as the accumulation of extra 0.2mm's on the wheel train meant I had to change my design a bit.

I'm happy with the meshing but would like to understand why there is such a big discrepancy. the blanks were all turned to within 0.01mm of textbook and DoC the same.

Steve

Hello, I have been trying out my newly made depthing tool with a variety of Mod 0.3 wheels and pinions.

On measuring across the runners, the distance is consistently 0.2mm more the theoretical (sum of pitch circle radii). Any less and they bind. Plus 0.25mm gives a good mesh.

I expected it to be more than theoretical but not that much. Am I missing something here or does this seem normal.

By the way, the tooth form is involute.

Cheers

Steve

I think I paid about a fiver each for mine, maybe less.

Steve

I picked up a few of these tiny M&W micrometer heads some years back and I've used them for a few projects.

Here are the component parts.

The locking nut knurls are scrap gears. The runner locking screws are M1.6 Allen screws with the head diameter reduced. I drilled them out with a 1mm bit for a couple of mil then loctited brass rod into it and filed flat to length. This prevents any damage to the runners when locking in place.

And here's the tool in action.

Cheers

Steve

Edited By Steve Crow on 06/09/2022 16:51:10

I've got a set of Dasqua digi calipers and they feel as good as my MItuyo. Lovely and smooth and nice feel.

I bought it because it was the only 100mm caliper I could find and I needed something compact for my watchmakers lathe and other small machines. Batteries seem to last for ever.

I also have a Dasqua 0-5mm analogue dial indicator, again bought because it was the most compact I could find. This isn't up there with my Mituyo's but perfectly adequate and I've used it 2 or 3 times a week for 5 years now.

In my opinion, they are good value for money and I would buy from them again.

Steve

I find that using a micrometer stand makes it a lot easier when measuring bore gauges.

Steve

Amazing. What is the scale?

Steve

You're right, I hadn't noticed that!

Thanks Martin. When I've finished making my depthing tool, I'll give them a good run round with a pinion and see if that does the trick.

I have considered something similar Martin but mounting it would involve much butchery.

If I could find a flexi drive that would fit through my main spindle, that would be ideal.

Sherline do a pulley kit to increase spindle speed to 10,000 but the faff of changing pulleys every few days puts me off.

What sort of diameters are the cutters you mentioned and the depth of cut?

Steve

Thank you Jason , I thought I was at the limit with depth.

It is not a question of speeding things up - my thought is the less passes I have to make, the less chance of an error!

I have a CNC rotary table so I cut the hub and rim under power and hand feed for the spokes.

No, I haven't started on these wheels yet, they are straight from the milling machine.

I have tried beyond 1200 but a tiny burr remains on the teeth.

I've cut a number of small clock wheels.

I find that when I try to clean up/polish the face of the wheel, whatever method I use, it throws up very fine burrs on the teeth.

I've tried adhesive lapping film stuck to glass (a method I use for sharpening my leather knives) and fine wet and dry but I still get a tiny burr.

Has anyone any suggestions for a method for this?

I keep hearing about Carat paper used by jewellers. Is that a solution?

George Daniels recommends flattened Water of Ayr stone under running water. Good luck to anybody trying to get that!

Cheers,

Steve

Edited By Steve Crow on 15/08/2022 18:16:37

I've had a go at crossing out some small clock wheels on my Sherline rotary table and mill. Here's a 48 and 73 tooth wheel. And a penny.

These are straight off the machine with a "fingernail" deburr.

I drilled out the corners first with a 0.4mm bit then milled out the rest with a 1mm 2 flute carbide end mill. The material is 1mm CZ120.

There was a lot of trig and calculations to get the indexing right but I'm quite pleased with the results. With the 0.2mm radius corners, there is a minimum of filing to do.

My question is, is there a better tool than a 2 flute end mill for this process?

I have been taking depth of cuts no more than 0.3mm so 4 passes to get through. Does any one know of a bit that could do this in 1 or 2 passes?

I have quite a few of these to do.

Please bear in mind that my max spindle speed (2,800) is an order of magnitude slower than ideal!

Cheers,

Steve

Here is one cylinder head with valve gear installed and a cam carrier behind it.

Valves, tappets and springs (and spares) for the other head.