Member postings for John Stevenson

Michael forget it.

Even though it's the 20" bed model it going to weigh the best part of 1 1/2 tonnes and it doesn't split.

It is a D1-3 as it's the same as the 30" model, just shorter although this one looks to be the full metric version as opposed to the imperial version with transposition gears.

The transposition gears are like hens teeth to get, they are half size, 32 DP as opposed to 16DP so you have to swap the whole set.

Be interesting to see how much it fetches as a decent full size CVA very rarely makes it past £1200 even though they will knock the socks off a Student or M250 or M300.

I ran one for quite a few years until I parted it out a couple of years ago to replace it with a larger, full metric machine.

I broke mine for spares as it was worth more for the sum of it's parts , especially when listed on Ebay.com as Monarch 10EE spares. The fixed steady made $600 on it's own, transposition gears made £400 in this country but would have made far more in the States.

As backed up by MAAG one of the better respected gear companies.

The late dearly lamented Gert used to say to me "When are you going to grow up ? "

I didn't realise it was an option ??

Michael,

Not read that article for many years so not familar with the reference.

I was going on what I'd read in a gear book years ago but as all my books are still at the other house I can't scan the page. From memory it was only like a concept drawing to explain the principle but in true Michael gilligan style will this do ?

**LINK**

.

Maag have used this idea for years on their gear grinders which have to have far more accuracy than we can hope to attain in the home shop.

so centre to centre of the slots from the central slot is 2" ?

Recently found a batch of alloy tooling plate sub tables for Tom Senior milling machines. I had these cut ages ago with the idea of machining them up with a series of tapped holes to use as sub plates on the bed.

Unfortunately in the depths of time I have lost the piece of paper that went with them that had the number and width of the tee slots on it which I need to lay out the holding bolts.

Anyone willing to have a quick measure up and post a reply please ?

Had the same happen a while ago.

A while ago I had trouble accessing the Yahoo newsgroups, two of which I run. Did a google and I wasn't the only one.

Tried a variety of options suggested and finished up with an ad-aware type program [ wasn't Ad-aware ] that cure the Yahoo problem but then I started seeing problems on other sites like this one having to log in etc.

What brought it to a head was a lot on inline logins where you had to enter numbers I had to do it twice, first time I entered the number in a box and then moved on it disappeared. When it stared acting up with the on line banking that really raised flags and I got rid of it.

This is W7 on Firefox.

Still having problems with Yahoo but virtually given up on these ijits now but this site works fine IF I don't have ad blockers running.

Good on you Windy.

Keep at it.

Wouldn't have thought so be hard to stitch two programs together as this goes from one side right through.

On seconds thoughts I might have cheated and used a form cutter in D bit form and hand coded the gear.

Not as bad as it sounds, send the cutter across at say 45 degrees to the centre point, then back, then index one tooth and rinse and repeat. Not the answer you were looking for but it's probably the correct one give the time period.

+1 for what Brian says.

I have a very, very good selection of taps and dies but I still tend to screwcut to relieve most of the material, then finish with a die or use one insert out of a Coventry die head as the tool to get all the right form.

I once saw a large set, probably in a museum or such where although they had been cut correctly they had been drilled from the front at an angle so the hole came out at the root of the internal tooth so someone else had also recognised a problem.

Going back thru some old photos and this one is dated end of May 2009 I did actually cut a herringbone with a centre rib but I'm now puzzled how I did it as the later Gearotic wasn't out then.

Not the clearest picture but the machine would have been one of the early X3's that Ketan at ARC used to sell a kit for. No idea what happened to the gear unless it's on the CNC display board down at ARC ?

Edited By John Stevenson on 09/02/2017 19:03:21

I'm still running a 486 on DOS on a weekly basis, works fine once the boiler is stoked

Not in my book.

The Rolls Royce of overpriced tools maybe.

OK,

I was involved from the get go on the development team with Art Fenerty of Mach 3 fame and Bob Landry.

Like a lot of software it grew in demand for added features and Gearotic 1 slowly out grew the ability of it's core program to build on.

This then changed to V2 and now to V3. Unfortunately feature creep has crept in and Art's goal now isn't so much gears an kinematic mechanisms. I slowly dropped out some where about late V2 but all isn't lost.

The early version, now known as Gearotic1 is still available from the downloads page although when you run it I think it says V4.xx or something.

I also think you need to have the latest version installed whether you use it or not to get certain dll files.

However once it's all installed you can then run the earlier version which works and is very simple. One drawback is it was never developed as far as the later versions so some things are missing line herringbone.

Now on to herringbone. These were developed by Citroen hence their chevron trademark.

Main use as mentioned was in very large reduction drives like turbines. The reason for the shape is that helical gears are quieter than spur as you have a gradual change over from tooth to tooth because of the angle. One problem with helical gears though is depending on the head they have a thrust value what is opposite and increases with the helix angle.

The Herringbone gear was developed to neutralise this as one side cancels the other. On a large reduction drive purely on helical gears, the thrust of the small pinion is enormous.

Now to the original question. The graphics draw the gear OK and code it OK but they can't take into account the cutter radius so yes you do get a small radius in the corner of the internal teeth. What really should have been done is to round the external corner to match. Art realised this but didn't do anything other than in usual Art "Lets go off and see just what we can do " mode he developed the knuckle gear. There is one in the top left corner of the web page with two helicals which are all gears I cut whilst checking code etc.

This is the picture.

But to get back to herringbone, yes they can be made on specialised equipment without the radius as Andrew says but it actually pays to put a central groove in to stop the extreme hydaulic forces when the lubricating oil gets forced into a sharp corner.

So anyone having problems with Gearotic and only wanting to do simple gears like spur, helical etc please have a go with the original program