After a short and frustrating day yesterday, where I struggled to mill the first of the motorcycle brackets to its 35mm depth because of all the table turning, I decided to leave the brackets and have a go at the gears project for a child’s electric jeep.
Arc Eurotrade managed to delivery the hobb very quickly so the first task was to create one test piece and two blanks followed by a hobb holder. The two blanks were simply turning jobs and didn’t take too long although I did have one new experience. I found on section of brass that could be turned to size and when trying to take cuts it was hard to cut. I tried both HSS tool steel and carbide tipped turning tool. I couldn’t get a good finish no matter what I tried. I thought that since it was a while since using the lathe it must be me. Eventually however, I changed to another piece of brass and lo and behold it turned beautifully whatever tool I used.
So the brass bar I used first must be something ‘special’. With the replacement brass bar in the chuck the two required blanks were soon finished to size. Once again the advantage of having DRO’s came clearly into focus because Thomas wanted the parts in metric and since I work in imperial you would expect that change to bring difficulties but it only needed just one button to convert the machine into metric.
After the proper blanks I decided to make another piece to the required diameter so I could practice cutting with the hobb since I have never used one before. Looking closely at the metric hobb you can see that the teeth are arranged in a screw pattern. Since the spur gears I want to machine require teeth at right angles I will need to have the gear blank offset to the cutter so some material to practice with is a must.
The next task was to make a hobb holder. After finding a suitable piece of steel it was over to the lathe. This time however I used the refurbished Myford ML7 with its 4 Jaw chuck because I wanted to ensure the hobb ran true. Once one sectioned was turned to size I threaded the end and made a nut to suit the 5/16” x 36tpi thread.
By the time I had completed the tasks above I had had enough so ended the session until the next time.
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Turning up the first blank
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I always use a plastic tray to keep project parts together
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The Hobb and the pinion to cut but on a longer shaft
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The practice piece, 2 blanks, the gear it will mesh with and the hobb complete with shaft
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Close up of the Metric hobb from Arc Eurotrade
About Mike Freeman
Hello, my name is Mike Freeman and I am a retired Chief Fire Officer from the United Kingdom with a keen interest in model engineering, silver caddy spoons and sea fishing. I live in the pretty fishing port of Brixham, South Devon, in the United Kingdom.
I am a sufferer of degenerative osteoarthritis, which impacts on the amount of time I can spend in the workshop, and is the reason why you will see seats and a stool in some of the photo's. I have only recently added the above sentence after a discussion with one of my Doctor's from the excellent pain clinic, based in Torbay. This does affect concentration one of the reasons why I double then re-double my measurements and set ups.
Before completing nearly 30 years of public service I and my wife Sandy, owned and ran, a small restaurant in Okehampton Devon. Prior to marriage I worked for my father in his various businesses, in the early days these were garages, which he bought in a run down state, then built them up before moving on, to start again.
I took every opportunity in those early days, to work in his workshop's
learning 'on the job' rather than as an apprentice. This, I suspect, is the reason why my building various model's in the early days, turned into model engineering, when funds allowed the required equipment to be bought.
My workshop comprises one half of a detached double garage. It has a
stud wall separating the two halves and unusually perhaps, its own
shower/toilet/washbasin compartment! (the true reason for buying the
bungalow - don't tell the wife!!!)
It is fully insulated with a ceiling and fluorescent lighting supplementing the one window. Several double electrical sockets are dotted around in
relevant positions.
Equipment consists of 2 lathes (1 Myford ML 10 and 1 Chinese variable
speed motor with etched glass DRO's), 1 milling machine (RF25 far East) floor standing pillar drill, Proxxon bandsaw, Warco bandsaw, 6" wire brush and polishing mop motor, 6" coarse and fine grinder, Proxxon mini drill, various benches and an engineers vice. I have just acquired a third lathe, a Myford ML7 which I am at present evaluating so I can decide which of the Myford's I will keep.
I have only just bought the Chinese lathe and had it fitted with DRO's prior to delivery. And what a bonus they are! So good in fact that I decided to buy another set for the Milling machine. Whilst my engineering experience can only be described as limited, I find the use of DRO's has affected my accuracy levels which have improved tremendously (although that's not saying much!) and would recommend their fitting to any model engineer.
Prior to retirement I built for my son's 17th birthday a Locost car. This
was a tremendous project and a great feeling when it passed its test. The book it was based on suggests it can be built for £250. Ours was nothing special in the sense of all new parts but still cost about £900 to build!
Hi mike, have been taking a keen interest during yor ml7 rebuild ,got one myself and rebuilt it last year from a box of bits!. was looking up some info on gear hobbing and cutting when this page popped up again, was that plastic gear shown in the photo a drive gear for an abu 7000 multiplyer reel by any chance?, not worth making them as they are relatively cheap new, stainless might be a result though, i am forever changing them for customers in my tackle shop, cheers, mick.
Hello Mick, thanks for the comment. I hope you enjoyed your Myford refurbishment as much as I did mine.
The gear was for a child’s electric jeep that the Dad wished to upgrade both the top speed and its torque. He did this by upgrading the electric motors from 12v to 18v and changing the gearing. A local watchmaker quoted him £500 for the job!
I do agree with your comment about readily available replacements though. I was asked to make an end nut for the crankshaft of a vintage BSA motor bike last year and after making the part in stainless steel I found that they were readily available on eBay for a low price! Still I gained in both instances by improving my skills.
Its nice to hear from a tackle shop owner though. You may want to have a laugh and look at my brother and myself’s fishing website. http://www.dartmouthfishing.co.uk
Kind regards, Mike