Thread: Adapting quick change tool post holder to suit Hercus 9" lathe

Dear members,

I need some advice on adapting a quick change tool post to my old Hercus 9" lathe. I have a second hand "Hamul" brand quick change tool post holder which measures about 75mm x 75mm x 45mm high. In the centre is an 18mm dia. hole.

The Hercus lathe compound top slide has a tee slot running across it. At a glance, it seems I will need a flat plate to suit the tee slot, with a vertical shaft attached, and threaded at the top for some sort of locking arrangement.

Has any member got a drawing of a typical adaptor to suit the Hercus lathe. I need to know how the adaptor plate is locked into the tee slot, and what sort of clamping arrangement is commonly used to hold the quick change tool post holder in place.

Also chasing a source for a low cost 4" 3-jaw self centering chuck, either new or second hand, to suit the lathe above. I presume the chucks being sold on eBay are of chinese origin, if so, are they any good?

Any assistance will be appreciated.

Regards,

Ken

Ken,
I'm no expert, but would think that the best way to go would be to fabricate a large T-Nut to fit the cross slide slot, instead of a plate. A T-Nut will give you a lot more material for a thread to anchor the vertical shaft to clamp the tool holder. An easy job on a mill , if you have access to one.
To clamp the tool holder, you would just need a large nut with an offset lever welded to it and just fit shims underneath so the lever is facing away from the chuck when everything is tightened down.
I hope that helps.

Oops....forgot about the chuck. Maybe Hare and Forbes can supply a chuck that will fit your lathe? Worth a quick phone call.
Also, ebay may be an option but I haven't seen many parts for them in the last few weeks I have been looking.

You do not need a drawing. the plate that slides in the slot for all four quick change tool holders I use simply is tapped to match the stem that holds the unit,they are not welded stems. If your stem is wider than the slot top you could sleeve it there.The guy in Canberra who is the Taig agent for Australia also sells another small and medium metal lathe and imported several sets of quick change universal units,I bought one of these and they are precision cut,easy to use,in fact delightful.If I get time over the weekend I will take some pics and put them on the site to illustrate what I have said.

Regards Peter

Hi Pete,

Nice to hear from you. Have not forgotten the info I promised you re cheap motor and inverter. Will have info on Monday.

Some pictures of your quick change tool post, to suit the Hercus, would be a big help. How do you lock the plate in the tee slot. Are there jacking screws or similar?

On another subject, what is the best way to remove surface rust, and polish parts back to their former glory? The hand wheels and knobs etc, on my old Hercus lathe, need refurbishing.

Regards,

Ken

Regards,

Ken

Hi Folks,
The Tapped Base Peter speaks of is in fact a Large "T Nut Inverted"
with the Stem screwed up tight and the Base filed or machined off
Flush. The "T Nut" grips in the slot when you tighten the Tool Holder
in postion for cutting.
Regards,
John.

Please find a pic I sat the bits on my freezer.

On the left hand side is a shop made tool holder held with an allen headed screw as a post that screws into the slide or form of T Nut.

In the middle lhs 4 tool holders,[one rear..larger internal cutting,
knurling tool with cutters,
cut off tool holder,
front conventional holder has a smaller
internal cutter in]

The holding bolt next right has a nut on top to lock the 360 degree move
with the sliding Tee Nut I cut with shoulders to fit the Hercus.
The large handle operates the cam lock for all the removeable holders,there is one in 6the holder as well.
This set is the one I bought from my mate who has the Australian Franchise for the Taig Lathes and imports a couple of smallish lathes and mills,he is one of natures gentlemen,a good guy.He only brought in some of the tool holders might have some left,they are precision ground from China.

In front is the original tool post holder minus the half moon piece I am always misplacing.It pulls the thing tight using the top bolt pushing down on the tool pushing down on the half moon,held in by the sliding part in the Tee Slot.

Next on the right is a 4 turret and yes the bolt is welded in the bottom of the slide with cutting tools held by screws. Hope this makes sense.

Regards Peter

Hercus 4 way on right is not welded on the post either at the bottom,some form of locknut holds the shaft on. Peter just noticed while putting the bits away.

Hi Pete and John

Pete, thanks for the photos. A picture's worth a thousand words. I can see now that it will be a fairly simple task to adapt my quick change tool post to the Hercus. I still believe it would be an advantage to lock the tee nut into the compound slide. This would mean that when the locking handle is released, the quick change tool post can be rotated without losing it's centre line position. Does this make sense?

John, thanks for your input, all is taken onboard.

Regards,

Ken

Many times I have been glad of the fact this way you can slide the unit in the slot to get closer or further away from the object in the chuck,so no I prefer the flexibility to normally centre the unit but have the ability to move it forward or back,it works for me. Peter PS I try to do the lightest of cuts when not in the centre of the slot so I understand what you are saying be careful of the leverage.

to lock tool post on to compound slide why not try making one piece out of 1 1/4 square bright bar,machine to tool post bore id,drill and tap end to suit clamp bolt.