1 Tonne Arbor Press suitability for broaching EN1A

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

We have a 2 ton arbor press and was broaching a 5mm wide keyway in 16mm bore in mild steel and couldn't do it. Had to put it on the hydraulic press, which recorded 4 ton at one point.

Not going to work.

The 6mm broach from ARC is 300mm long but the press only has 150mm of daylight.

Even the 3 tonne version of this type of press only has 280mm of daylight.

Sorry but you need a broaching type press as opossed to an arbor press.

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

I have a 1 Tonne arbor press and have no problems broaching metal of any size, You just need to remember to graduate the cut with bigger sizes, the same way a gun barrel was traditionally rifled by shimming the height of the cutter (albeit in a more complex mechanism).

Often times i use the arbor press to get it started square to the barrel with the appropriate collar, and if i run out of room i place the workpiece in a vice and finish the cut with a hammer, its pretty safe and it works so long as you don't hit like a madman but please dont take that as the gospel.

Ps. I see the image of the work piece you have kindly loaded, I can see why you would want to keyway that, may i recommend that you actually make that whole shaft square? You either file or broach the female part square and it would absolutely hold fast, it's a bit more difficult but the choice you go with will probably be the most sensible one and easier route of broaching a round shaft.

Michael W

Edited By Michael Walters on 27/03/2016 17:42:47

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

Hi David,

I used a home made slotting tool recently to cut a 4mm wide keyway in a freecutting EN1A. Takes a bit of time but worked well.

Here is a video of how another man cut a keyway, and a description.

Thor

Depending on the torque being applied is there any merit in cross pinning the handle to the shaft. Maybe a taper pin turned flush to the bush.

Martin

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.

Could you get away with a semicircular top on your key and just mill down the handle?

The facetious option is a cheap 5 ton bottle jack and press upwards using the underside of a parked lorry to press against....

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

How much force is likely to be needed to pass paper through the press? I would have thought a 3mm keyway would do, you could always use two on opposite sides if needed.

I have pressed 1/8" broaches through with mu drill press, larger ones make friends with someone who owns a hydralic press.

I have also planed 3/16" keyways through 1" thick steel on the lathe, time consuming but easy enough, see below

J

Edited By JasonB on 27/03/2016 18:27:59

David,

Martin's cross-pinning sounds good [except perhaps for your choice of three spokes]

Alternatives:

1. Woodruff key [only requires broaching the hub, not the shaft]
2. Substitute a cylindrical key [i.e. a dowel], which might usefully be threaded

MichaelG.

.

Note: (2) works for Myford ... see fourth picture here

Edited By Michael Gilligan on 27/03/2016 18:41:29

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.

Drill half and half into shaft and handle boss (on the joint line) This assumes that the two are a good fit and tap 6mm, screw in socket grub screw, job done Any slack in the fit and this method is not likely to work as you will not be able to tap the hole. No need to go right through 12/13mm deep should be enough.

David,

When I slot keyways I place a suitable piece of wood between a chuck jaw and the lathe bed, put the key in a convenient keyhole and a wire loop around the keyhandle with a weight in the other end.

My slotting device mounts on the cross slide so I have to remove the topslide.

Thor

Round keys used to be common. Put your hub on the shaft. Drill a hole and ream to size. Use a dowel pin or piece of rod as the key. My South Bend 10K lathe has a round key on the crossfeed crank.

The hole should be centered on the OD of the shaft.

David

Just turn off the electric to your lathe. Tie a piece of string round the chuck key and put a weight on the end. Insert chuck key into chuck in the 12 o'clock position, and place a small block of wood under the forward pointing jaw of the chuck, the dangle the weight over the edge of the machine.

Although the method of racking the carriage backwards and forwards to cut a slot sounds hard work it really is very economic in materials and time...and you would get what you wanted.

Pete

It's usual to mill the keyway in the shaft not broach it, much like you would use woodruff cutter to mill the shaft for the key.

J