A Jacobs Gear Hobber making parts for itself!

[@johnmcclain3887]

That looks like a nice piece of gear when you've got it all together and fit up well. I make tooling on a regular basis, and highly recommend thrust bearings on all pertinent shafts. That looks like a machine built by Dave Gingery, some twenty or so years ago, here in the states, some basic principle, design, not saying a copy, but a good basic design from a century and more ago. It's good to see some of the Brit machinery I've seen in print, without a pic, for most of my life. Thanks for this bit of magic.

[@medsteadengineering]

Yes thrust bearings would be an improvement. I have not had time to use it much (working on our steam yacht too much!). The design was published in Model Engineer in the early 1980s. Apparently Mr Jacobs was a professional engineer who was involved in gear making in his work. On retirement he decided to design and make the hobbing machine for his own use at home. The castings and drawings are still available from College Engineering Supplies in the UK.

[@marianodiaz461]

@@medsteadengineering I made mine without any castings, there was a mention in the original article that the designer used a piece of steel beam for found in the side of the street for the machine base

[@campbellmorrison8540]

Love it, definitely Jerry built but equally obvious Jerry knows what he's doing :) Im still trying to set up to make an ordinary pinion

[@medsteadengineering]

I've always found german- built tools to be of very high quality 😉😜

[@RustyInventions-wz6ir]

Very nice machine

[@RustyInventions-wz6ir]

Just found your channel and subscribed

[@mpetersen6]

It doesn't really matter what the base ratio of gear hobber is. The appropriate gearing for cutting a certain number of teeth is just the base ratio divided by the number of teeth. One thing we did with our gear hobber at where I worked was to make up change gears with from 22T to 75 or 80. As the base ratio of the machine was 30:1 cutting any gear was simply a matter of using a 30T driver and a driven the same number of teeth. We did the same thing with the feed gears. About the only time we had to use a compound gear train was for cutting helicals.

[@peterfitzpatrick7032]

No fear of the universal driveshaft introducing cyclical variations in rpm being impressed on the blank ? 🤔 Nice little setup you have, a shame you haven't more space... 🤗 From the Emerald Isle 😎👍☘️🍺

[@malcolmduckett1626]

There are two universal joints in the shaft, and they are phased so that the variations cancel each other out - just like on your car....and besides, you are talking about a variation frequency of 30 (or is it 60) times per tooth, so I really doubt you could see it, let alone measure it... 😃

[@sky173]

What a great idea. Where do you get that U-joint and shaft for the R/C car? I have an old Atlas milling machine that I'm rebuilding and that just may work nicely. EDIT - I just noticed that you may want to check the phasing of the u-joints (@ 1:37). It looks a little off, but it's hard to tell in the video. :)

[@medsteadengineering]

Just check eBay, thousands there 😁

[@marianodiaz461]

I made one of those ,about 20 years ago , almost finished , because I wanted to ad the differential to cut helical gears.. can someone please point me to the differential mechanism article?

[@medsteadengineering]

I don't think a design was ever published, although there are some discussions of one on-line... sorry.

[@marianodiaz461]

@@medsteadengineering just looked at a little article in the model engineering forum, found it thsnks to google

[@renatomartinez3183]

Very smart and clever gadget,if isn't much to ask? What's the speed of the Gear blank? Assuming that the electric motor would be 1200 r.p.m's!!

[@malcolmduckett1626]

The motor runs at 1,400rpm (50hz sync). The speed of the gear blank depends on the number of teeth being cut on it. So a 50tooth gear would be turned at 1/50th of the speed of the hob, a 26tooth gear blank at 1/26th of the speed of the hob. The hob speed depends on which belt position of the drive belt, but about 150rpm...

[@BensWorkshop]

How are you finding gear making on the Jacobs hobber now?

[@medsteadengineering]

To be honest other things have consumed my time. However, I plan to make some timing gears for a vintage bike I have been working on, so we will see 🙂

[@BensWorkshop]

@@medsteadengineering I would be very interested to know how it works in practice.

[@medsteadengineering]

@@BensWorkshop yes, the test gears and worm wheel looked (and worked fine) but the timing gears will be in much tougher steel...but I did buy a brand-new hob...so we will sees

[@bobsnedker1176]

Made one years ago, run mine a lot slower though, saves a lot of movement on the parts, buts cuts gears very well.

[@medsteadengineering]

It is a fun thing, some fettling and fitting got the movement under control!

[@ColCurtis]

How did you get that lathe and mill into that tiny closet?

[@medsteadengineering]

Carefully!😁 Draw a CAD floorplan, then little rollers and large levers🙂

[@gutsngorrrr]

I'm looking at getting one of these machines and wanted to know what the limitations on this machine. What size external cut standard gear can be cut.

[@malcolmduckett1626]

Mark, they are not a commercial/professional machine (they would cost $xxxxk), but they do work, about 6" diameter max. I will report as it gets used for more projects, all so far have been bronze or aluminium....

[@gutsngorrrr]

@@malcolmduckett1626 Thanks for getting back to me. I understand the machine is basically a hobby machine. I'm just hoping I'm able to use it to make some of the less common gears for my Myford lathe and maybe a few other project's. I did see a lovely Micron, but I have got the room for something like that and I haven't got £5000 either :)

[@malcolmduckett1626]

@@gutsngorrrr yup it is absolutely the animal for that job and more....😃👍👍

[@gutsngorrrr]

@@malcolmduckett1626 I look forward to seeing how you progress. I have now purchased one and can't wait to give it a go, though I imagine it's going to be a steep learning curve

[@gutsngorrrr]

Out of curiosity, is the any documentation or manual for the Jacobs hobber? If not, what's a good book to get to help me understand how I set up all the gearing etc on this machine.

[@malcolmduckett1626]

The original Model Engineer's Workshop (and I think Model Engineer) articles were prefaced by a articles on gear hobbling, and the plans provide tables of gear chains... As I was using non-standard gear sets, I wound up writing a program to provide lists of tooth numbers and gear chains, it's not too hard...

[@patrickfischer2264]

Need to incorporate a fly wheel

[@medsteadengineering]

I know a number of people have said it helps, so far it does a good job without... but maybe an upgrade for the future!

[@muraliradhakrishna167]

Machine needs more rigidity