Marlo A3 Milling Machine

Back asking for more advise please.

A previous owner fitted the intermediate pulley as shown below, together with a DIY motor mount, all well done.

That mounting plate is big and heavy!

Now, do I leave well alone or remove?

I do not, however, have the original motor mount with shield that bolted to the spindle pulley shield, that I do have.

I'm very tempted to leave well alone a see how I get on with that extra pulley in the system with VFD.

Marlo A3 Album added that has a side-on photo of that big plate.

Geoff - A cup of Earl Grey makes a change from coffee

The motor on my Marlow mill is a 3 phase flange mount and it is possible that in the past the motor failed and the previous owner fitted a foot mounted motor and to get the drive to work added the pulley.

Mine runs fine on a micromaster converter and I tend to use the middle ratio on the pulleys for most jobs allowing the micromaster to vary the speed.

Does yours have one belt or two?

Bob

Bob is right in his suggestion that a previous owner has used a foot mount motor (mounted on that bracket at the rear) and added an intermediate pulley to increase the range of speeds available on the pulleys, and has removed the original backgear.

Originally had a flange mounted motor with 3-speed pulley drive and a further 3 speeds available through the backgear.

I don't think there is much option other than to stick with what you've got unless you want to do another complete redesign of the drive system.

Picture attached of how it originally looked. Apologies if you already know this

Phil

Note for H&S -  front cover removed so we can see the innards

Edited By Robbo on 18/10/2014 21:57:56

Mine is not like that as it has no gear wheels just belt driven 5 speeds originally but variable now due to the micromaster converter. I think mine originally went from 375 to 2250rpm and the geared 6 speed version from 85 to 1450rpm.

Edited By Bob Brown 1 on 18/10/2014 22:06:47

Bob,

I think the detailed spec varies depending on where the machine was built. You can see from the plate that Geoff's was made by Victa Engineering, I've forgotten where that was, but mine was made by Dronsfield Brothers in Oldham.

Even so my feedscrews are different from those detailed in Dronsfield own advertising literature. There is sparse information on when and where they were built

Phil

Memory let me down again, so once more talking bo****ks.

Found my Marlow advertising leaflet, and there were 2 drive options, the 5-speed direct, and the 6-speed with backgear and 3-speed pulley. The 5-speed is illustrated on the leaflet.

So Bob's and Geoff's are the 5-speed option, mine is the 6-speed.

Bob is quite correct about the speeds, 375 - 2250 on the 5-speed, and 85 - 1450 on the 6-speed. Given the noise the backgear makes, a VFD would make for a quieter life on the 6-speed.

Geoff, with a VFD fitted, why not forget the intermediate pulley and have a direct 5-speed from motor to spindle.

Oh, and Victa Engineering were in Maidenhead.

Phil

On either of the original drive designs changing speeds was reasonably easy as it it's just a case of releasing the lock and moving the motor forward, change the position of the belt and then tighten up and lock. Not sure how this is achieved on the three pulley set up.

Mine runs almost silent!

Bob

Thanks once again guys.

Bob,

One belt, and the motor had a 3-step pulley ranging from 65-48mm measured at the outer edges, 5/8" shaft.

New motor has 24mm shaft so a new pulley ordered from RDG.

The intermediate pulley is easy to remove, but I think I will use it as a jockey pulley, as a belt from motor to spindle will be somewhat long with possible mismatch with pulleys, so a bit of tensioning will not go amiss I think. Can always remove it.

Robbo,

Its the first time I've seen that set-up.

The motor I've taken off is a 1hp Gryphon, foot mount.

The thought of redesigning the drive train fills me with the heeby jeebies. Let's play with what I have.

Geoff - Those Russian dash cam videos make me glad I drive in this country!

!WHOOHOO!

It's actually running, after sitting in the Workshop since 2008

Haven't used it in anger yet, but photos and details to follow.

Just one more thing to do, and that's to connect power to the Power Feed motor, but I need help please with wiring it up.

The machine came with a box of switches and cable, but no info on how they should be connected to the motor.

There is a connection box on the side of the motor, with five wires coming out, namely, white, red, green and two yellow.

No idea if the motor even works or not.

Geoff - Satisfactory week

Mine did not have a power feed so can not help with the wiring but I have fitted a BLDC motor and variable speed controller with a belt drive which works really well.

Bob

Hi Geoff,
Is there any information on the motor to suggest if it AC or DC ?

Les.

As the original motor is 3 phase then as a thought, a 3 phase motor only needs 2 phases reversed to change direction. That said it could be single phase a pair as run terminals, a pair as start and an earth, I doubt very much if it is original that it is DC.

Anything under the motor terminal cover?

Bob

Can you not change the Acceleration Time parameter? On my Mitsubishi VFD it's parameter 7. Parameter 8 is for the Deceleration Time.

More photos just added to the Album.

Replies:

Bob,

Details of mounting the BLDC please.

Les & Bob,

Cannot see any terminal cover or info about the motor.

As can be seen in the photos, the motor is at the rear of the column and up against the wall, and even a mirror doesn't show any plate that may of course be on the underside of said motor.

General:

Fitted the new pulley to the motor shaft then an 'Oh' as the largest step prevented the motor from being bolted to the upright, so four spacers made from 20mm sq tubing and all well.

Now came the time to 'gird ones loins' and heave that combination up onto that aircraft carrier size plate on top of the milling machine, and catch my breath once done.

Now to get that unwieldy assembly into place to slide into the square 'dovetails' but an 'OH B@LL@cks' as the pulley got in the way! Once I'd calmed down and thought in a calmer mood, I realised that the only solution was to remove one of the pulley steps, and for some reason chose the largest diameter step, so off it came, into the lathe and the use of parting tool and boring bar had that step cleanly sheared off. Didn't fancy reducing it to swarf, so now have two pieces of possible useful packing.

Pulley back and it all fitted as before, ordered a V-belt for motor to intermediate pulleys and wired up the VFD whilst waiting for the belt. I could probably remove the motor spacers, but life's just too short, so they are there for keeps.

Switch everything on, twiddle the VFD frequency knob, and motor sprang into life, for the first time since I got the machine.

I did a jig around the Garage floor in celebration and relief.

The VFD is on a bracket that hangs from the OverheadCrane DIN rail, and easily taken out the way.

Just need to sort out the table power feed now.

Bolted one of the aluminium trays and the packing block set to the LH and RH side of the column respectively.

Geoff - Finish the Tom Senior next.

My mill is a tad inaccessible at the moment as I await a load of concrete (Wednesday) to complete the floor and once that is dry (week or 2) arrange the workshop/garage.

Its all in there somewhere!

Need help from the Collective please.

Last stage to finish the Auto-eject drawbar, made from the Hemingway kit.

I need to machine the half round 1/2" notches in/around the periphery of the handle.

Any ideas please.

This set-up for marking them out is just a little light weight for either a slot drill or milling cutter:

This on the Boxford 6" just produces such monumental chatter, it feels as if the shaper will shake itself to pieces:

Have used the 3mm cutter to remove material first:

Geoff - Actually getting things done

If I was doing that job I would use a round nose (ball) cutter in the mill

Edited By Bob Brown 1 on 13/12/2014 14:21:53

"Damn and blast" as my old man was fond of saying when something obvious was pointed out.

I have one of those, as well as the Excel filing machine that has been giving me verbals for not remembering what it's used for.

May have already made too much of a whatsits so far, but will see tomorrow.

Geoff - Time for a cup of Earl Grey to calm down.