Ajax AJ8 Milling Arbour removal

Hello, its me and my Ajax again...

I am trying to remove the arbour, but I can't seem to work out how.

I believe there is a draw bar, but I can't seem to see any access.

The end of the arbour appears to be a machining mark, while the pulley nut, had a pin that was soldered over. I tried numerous times to undo it before trying heat to loosen it. It was then I discovered the pin. The inner boss of the arbour has a hole in, that indicated a bar should be used to unscrew something?

Am I missing something? If I try anymore force on the nut of the pulley wheel, with a bar in the arbour boss, I fear twisting of breaking the overhanging support.

I assume it is a standard fixing?

Many thanks,

Nicholas

Hello Nicholas,

I don't know the model, but suspect the arbour is located by a morse taper fitting which is pulled into location by a drawbar from the rear at the pulley block. The front end would be supported by a casting from the overarm with a precision bush in it. That is the general pattern for horizontal machines

You say there is a pin through the nut at the rear, indeed a hole is visible in your picture. I don't see any purpose for that at all. I think that the drawbar has been pulled up very tight and you will need to take it by surprise to free it off

Try fitting a drive belt to the pulley on the largest diameter, twist it up with a bar close to the pulley to get a good grip on the pulley and anchor the bar to something on the machine body to stop it moving.

Now fit a ring spanner on the nut, not open ended you need the full ring contact and belt the end of the spanner with a hammer; don't be timid about this, a good hefty whack will be needed. That should free the drawbar thread so that you can unscrew the drawbar. Undo it by a couple of turns and with a lump of flat brass on the head of the nut, give that a good belt with your hammer to jolt the tapers free.

After this treatment it should all come to pieces in the usual way

Best of luck

Brian

Edited By Brian Wood on 02/08/2022 17:38:41

Picture 3 looks like a long hex nut pinned to the round drawbar end like on my Warco Mill-drill. however can you explain picture 4. It looks like a view down the pulley as if something more than just the nut was removed. ???
If the inside of the pulley is threaded and the bit removed with the nut is threaded on the outside perhaps it is meant to be screwed in to push the back of the drawbar to force it out.
Or maybe the drawbar is too short and had a screwed on extension that has come off.

The front of the spindle looks to be a stepped flange to provide the drive so is just backed by eg a Morse 2 or 3 for alignment and that as usual is jammed.

Nicholas,

Slacken off that drawbaw, maybe half a turn. Tap the hex head with a soft hammer. This will loosen the mt3 fitting. Then undo drawbar fully and remove arbor.

I suspect that the rear nut provides preload for the spindle bearings as well as holding the pulley on, then the pin hole was drilled to stop it being messed with / vibrate loose later.

I assume the blued part of the arbour has a hole in it so you can tighten the cutters.

This Ajax was never designed for a vertical head so why would the arbour need to be removed?

Most horizontal mills will bend the arbour without the support arm and bearing in place when you tighten the cutters.

Edited By Dave Halford on 02/08/2022 20:58:58

Hi Nicholas, did you manage to remove the drawbar? I have a similar machine and the drawbar is easily removed by undoing the hexagon head (mines standard right hand thread, but yours maybe left hand) a few turns and then giving the end of it a tap with a soft faced hammer to loosen the far end as AJAX says. The arbour end has a 3/4 in’s plain shaft that fits into the mandrel.

I’ve made a couple of fittings to fit into the end of the mandrel, one that will take a fly cutter and another threaded to match my lathe spindle nose.

John.

h Hello Nicholas I have a Ajax iscrapped if you require the spildle let me know also a BSA chuck 3morse taper free to a good home of course