Crank handle method and sequence

So I'm missing a crank handle for my new to me bridgeport. I didn't realise just how expensive spares are when I bought it so now thinking it could be a good project. Although it has me worried (difficult)

So what would be the proper sequence?

I'm thinking, rough it to the various diameters between centres. Then turn the tapers and balls (going to be a seperate thread!!) Then mill the flats and drill the hole. Although how would I fix it for the mill work. Or would it be better to do the mill work first? Would it be best to start with round or square stock?

I find working up the plan difficult! Cheers Colin

Edited By colin hamilton on 18/02/2022 20:56:03

Suggest simplified handles. If you make the centre section from rectangular bar or plate and add a simple turned counterweight at left end and spinning handle at the other, it will take a lot less time and do exactly the same job. The spinning one can be a plain cylinder , a cylinder with a low taper halfway up the OD, or the fancy original style. All will work equally well. An ordinary shoulder screw / stripper bolt makes an excellent pivot for a bronze or aluminum spinning handle.

Different people have a different approach to making the part but I would just hold it in a 3-jaw chuck.

Cut a piece of round bar longer than required. Turn the small ball and taper, then the middle ball and taper. Then take it to the mill to machine flats, holes and keyway,. (un-turned end used to hold the part). Then return to lathe to turn big ball end.

Paul

If I was going to reproduce the handle I'd use a hydraulic copying unit and template:

Final parts:

But I wouldn't reproduce the handle. Instead I'd design, or buy, something simpler and less dangerous. I took one of the table handles off my Bridgeport. It's the right height to hit one where it hurts if it catches you while under power feed.

Andrew

Last time I looked you could find acceptably close copies of the genuine fixed handle for around £10 to £15 out of China from the usual suspects. Might well have to modify the bore and keyway but that's far easier than making a copy from scratch.

Even with Andrews hydraulic copier to help.

I'd probably just go Beaver style. Chomp a bit of plate down and affix a shoulder bolt with a bit of tube running on it for a handle. Very much a place where pug ugly but "Well it works." is plenty good enuf. But if you haven't suitable stuff to hand that won't be much cheaper than a copy.

Power feed Bridgeports should have freewheeling handles so getting clonked isn't really an issue. But best to make sure they really are free running as there are places where the impact from a stiff one will still make your eyes water. If you don't know the tricks unsticking a stuck up freewheeler can be frustratingly hard. Once you have got it free there is a fairly tricky knack to twisting the grip so the drive pin remains engaged when turning. Even after 15 or so years I still sometimes drop the drive mid adjustment.

Clive

Edited By Clive Foster on 18/02/2022 21:55:40

Edited By Clive Foster on 18/02/2022 22:11:38

Coincidentally I made something very siliar a couple of weeks ago, in my case for the "x" travel on my Centec mill.

I cheated and made it in three parts. First the centre boss - which I decided I didn't need to make as a ball - so I milled two flats on the boss and hid two M6 tapped holes in them. I then made the two arms of the handle, with balls and tapers to suit, and drilled and tapped the inboard end of these M6 to match the boss. A short grubscrew in each preserved alignment and held the arms in place while I welded the arms to the boss.

Having now established the orientation of the handle part I drilled and tapped a hole in the end of the small arm into which the handle was then loctited. A bit of fettling around the welds just to tidy it up and Robert is your Mother's brother.

It's not as pretty as the examples above - but it'll do a good turn nonetheless.

HTH Simon

I know I've seen this in a book, but can't remember where. I found this, though:

**LINK**

Mike

Edited By MikeK on 19/02/2022 03:27:13

Thanks everyone. I will definately go 'good enough' to start with, if for no other reason than needing to operate the mill when making the 'posh' version!

I've looked at the Chinese versions. They are now about £20. The bores are a bit smaller and I was worried there might not be enough meat left after machining.

I've no idea what that hydraulic unit is so I'm thinking its probably not best suited to my skill level!

My Mills handles are fixed in x and y (it's the y I'm missing). The z axis is free spinning.

Paul - I love the idea of leaving the square on and coming back to the lathe to finish. That's exactly the sort of sequencing I'm struggling to get me head round.

Simon - I hope you don't mind but I think I'm going to copy your approach 😉

Cheers Colin

Colin - be my guest.

Do "show and tell" when you've got something workable.

Rgds Simon

Full write up on ball handle's in Geo H Thomas's Model Engineers workshop book, still available from Tee publishing. Much else besides in there , essential reading.

Dave

Thanks, now on my B'day list!

Don't forget the twist to engage feature of the Bridgies original handles. On power feed saved many accidents.Perhaps that's why the expense for an original.

Regards Ian