Member postings for David Cambridge

I’ve just bought a cheap and cheerful ebay Chinese drill chuck. It’s nothing unusual and has a b16 taper, and takes drill bits from 1 to 13 mm.

It has the problem that once the three jaws semi clamp the drill bit I can go on turning the chuck key for ever without it clamping any further. Does anyone know of a quick fix before I send it back ?

Thanks

David

Thanks everyone! I do enjoy making the videos, although it does seem to make everything take twice as long

I've also just passed on the compliments to my wife as well. She's says thank you very much to!

Edited By David Cambridge on 01/05/2016 20:06:22

Thanks Bike Pete!

At last my wife’s printing press is finally finished and I can get back to model making!

Thank you everyone that’s given me help on this forum getting the thing done! (bent rollers after welding, milling slots, understanding bearings, and how to cut key ways!)

David

I’ve slowly been assembling the kit I need to try small part aluminium casting, and as the weather was nice today I thought I’d give it a go. It wasn’t perfect, but for the first try I was quite pleased.

David

So in the end I went for the 'rectangular bottom & semicircular top' option. Photo below.

I was going to make the ‘semicircular’ top next – but thinking about it, is there anything wrong with some sort of grub screw to hold the key in place ?

Anyway, thank you again for all the help, and thank you Simon. That was a very kind offer but it looks like I’ve got a work around.

David

The problem with Michaels Option 2 is that I don’t have a way of drilling longitudinally down the shaft – other than with a hand drill, but I don’t think that would go well.

I still like pgk pgk’s idea ‘Could you get away with a semicircular top on your key and just mill down the handle?’. The only thing that’s putting me off is that it doesn’t seem to be gaining any momentum on this thread!

David

If a 3mm keyway would do, then life would be easier. The machine mart arbour press has a height of 138mm – and Keatons keyway broach for 3mm is 128mm.

Pgk pgk

‘Could you get away with a semi-circular top on your key and just mill down the handle?’

I was thinking about that. I can’t see any reason why that won’t work. Then again there are a lot of things that I haven’t been able to see a reason why it won’t work – until I try it! Does anyone see any problems with this idea?

David

Thor – that lathe method looks pretty good. The only problem is that I have no way of locking my chuck ?

Martin – that might be the way forward.

Thanks Michael

Making the shaft square is not a bad idea at all – my one reluctance is that the shaft and roller are now all one. Welding it together, and then turning it to size has taken so long I’m keen to avoid touching it as much as possible (making a mistake and having to start again would hurt!). I figured that cutting a keyway in the handle might be easier – but maybe not.

David

Thanks both.

That doesn’t bode well for my original idea – but at least I’ve found out before spending money!

It’s for attaching the handle to the shaft of a printing press I’m making for my wife (see fusion 360 mock up below). If anyone else can think of a way of attaching the handle, or cutting a keyway I’d be very grateful for input.

The hydraulic press would no doubt work – but it’s a lot of money to spend for a one off.

David

Hello All

I need to cut a keyway through a 19mm diameter bore, and depth of 24mm in EN1A.

I’m thinking of buying the below 1 Tonne Arbor Press from chronos , together with a 6mm broach and associated kit from Keaton.

http://www.chronos.ltd.uk/acatalog/info_SMA1252.html

Before I spend any money I’d be grateful if anyone has enough experience to confirm what I plan will (or will not work) ?

Thanks

David

Thank you everybody. I’ve just spoken to a very helpful chap at Hemmingway and he can supply me a pair.

David

So armed with my new understanding, I can now ask the original question more sensibly.

Does anyone know where I can get helical gears of angles other than 45 degrees. I get the impression from the HPC web site they will make gears to order, but if I can find them on the shelf that would probably be better ?

Thanks everyone. The missing part of my understanding was the cos(A) in the formula

David

I think there is still something fundamental going on that I don’t understand.

If I want a 2:1 ratio between the crank and cam shaft, and I look at helical gears on hpcgears.com the diameter of the large gear (I’d use this for the cam shaft) is twice that of the small gear(Id use this for the crank shaft). Since PD = N/DP that seems fair enough. But, when I look at the photos like the image of a Find Hansen engine at the top of this thread, the two gears look either the same size or the opposite way round to what I was expecting ?

David

‘The life of the toothed belt used on the Perkins Prima diesel was never really known. We never managed to fail one in development; so arbitarily set the change period at 70,000 miles when other cars were setting periods of less than half that.’ - My first car had one of those in, and without doubt it was the most reliable engine I’ve ever had in car.

‘I've never run across any car engines with timing belts run wet’. From my experience with Ford focus cars I’ve never come across any that run full stop. My first bar stock engine was more reliable. Under warranty, unfixable by the garage ‘technicians’, and ultimately sold at financial loss to myself. I'm still bitter about it!