Yet another QCTP thread (BXA on AL320G)

[timoxx4]

Its 24mm. Do you think there is enough room inside the QCTP for this to be bored out ? I don't suppose you can take a picture of the bottom of your QCTP so I could see what it looks like ? Or take it apart to see what room might be inside for a 24mm hole ? That would be a great help if you can ?

Cheers.

 

[rodw]

Its 24mm. Do you think there is enough room inside the QCTP for this to be bored out ? I don't suppose you can take a picture of the bottom of your QCTP so I could see what it looks like ? Or take it apart to see what room might be inside for a 24mm hole ? That would be a great help if you can ?

Cheers.

I think you could get away with it. Here is the base and it has a 25mm or so threaded hole.



This screws in from a slotted top on the top side


I think you could shorten the treaded post but I did not dissassemnle anything to check. I have had it apart before and it is tricky to put back together but it is doable.

 

[Journeyman]

Timoxx4 - Found a picture (attachment) of my AXA type 100 which shows what is inside. Basically there is a central tube that holds the QCTP together. The bore in mine is 14mm but the larger BXA type 200 has a bore of 16mm. The tube isn't that thick so I doubt if you could machine it out to 24mm. If you want to take yours apart the end of the tube is a left hand thread.

I had a similar problem on my Warco WM250 (UK) and ended up machining the boss. You can see details on my site - Fitting a QCTP

Good luck
John

 

[rodw]

Timoxx4 - Found a picture (attachment) of my AXA type 100 which shows what is inside. Basically there is a central tube that holds the QCTP together. The bore in mine is 14mm but the larger BXA type 200 has a bore of 16mm. The tube isn't that thick so I doubt if you could machine it out to 24mm. If you want to take yours apart the end of the tube is a left hand thread.

I had a similar problem on my Warco WM250 (UK) and ended up machining the boss. You can see details on my site - Fitting a QCTP

Good luck
John

That is actually quite different to the mechanism in mine. With mine turning the slotted head withdrew the centre shaft from a thread at the bottom So the column is a single part.

 

[timoxx4]

Thanks for the pictures. That helps a lot.

Hmm looks like I might have to cut my boss down I think. If I bored out the bottom hole on the QCTP it would pretty much wipe out that entire threaded portion on the bottom.

Only problem now is I need a tool post in the lathe to machine down the boss but cant because the piece with the boss on it will be in the lathe chuck :wall:

Also if I machine the boss down to 16mm to fit inside the QCTP it would be very thin in the walls as the hole in the boss where the original bolt sticks out of is 14mm. So the cast boss would only have 1mm thick walls left ?

I am not real sure what to do now? I didn't want to remove the boss completely as I think it would add a lot of support to the tool post. And I would also like the option of being able to go back to the original tool post if need bee.

Any ideas ?

 

[timoxx4]

That is actually quite different to the mechanism in mine. With mine turning the slotted head withdrew the centre shaft from a thread at the bottom So the column is a single part.

It should be the same I think. The two pieces might just have been stuck together when they came out but the slotted head piece should turn inside the scroll piece so must be 2 pieces or it wouldent work.

 

[Journeyman]

Timoxx4 said - "Only problem now is I need a tool post in the lathe to machine down the boss but cant because the piece with the boss on it will be in the lathe chuck

"

Yes that's exactly the problem I had and I ended up making a new tool post that fitted directly to the cross-slide. I also ended up with a very thin boss 14mm dia with an M12 thread down the middle but more by luck than judgement the cast iron didn't crack. You are right about the slotted head piece it goes down the centre of the actuating mechanism which rotates around it, as you say it wouldn't work if it was all one bit. The thread or ramp that makes it work is a three start left hand acme thread that pushes the wedges down to clamp the tool holders.

The boss on your lathe doesn't look as high as mine was perhaps you could make a really thick washer about 60mm dia to fit over the boss and fit the QCTP on top of that if the vertical height allows the tool to come down to centre height!

John

 

[rodw]

I think timoxx4 was right and I was wrong. Mine is the same.

The other alternative is to look at the reccommended tool post for this lathe.
http://www.machineryhouse.com.au/L295

It is a very good bit of gear and I think from memory it already has a recess cut into the base. Shame about the price!

I think if you made a spacer so the tool post sat above the boss it would be too high for most tooling.

I've got 1 or 2 16mm tools and they just fit in at centre height, mostly I use 12mm.

 

[timoxx4]

Wow, yeah $500+ is a bit out of my range for a tool post. Looks like it would fit straight on though. Tool holders are a bit pricy also for it.

Yeah I try to use all 12mm tooling with my lathe also. It would be interesting to see if they might sell just the cross slide part for this machine and I could have one to machine all I like and not worry about ?

 

[rodw]

They will sell parts as a mate bought a spindle so he could build a CNC lathe.

The otber alternative would be to make your own crossslide. I've thought about that a couple of times. I'd probably use Cast Iron which you can get from George Weston. They cut to size.

 

[timoxx4]

The otber alternative would be to make your own crossslide. I've thought about that a couple of times. I'd probably use Cast Iron which you can get from George Weston. They cut to size.

Yeah well that could be a possibility. One like John's only bolted with T-nuts to the carousel maybe ?

 

[ronboult]

Hi Rod
Saw your post on adapting a BXA to your new lathe and it gave me confidence to tackle mine. Just bought a Sieg Runmaster 330x 1000 lathe and it had a old style toolpost with a insert post. No T slot in the compound like American machinery.



It had a european post similar to yours. The shaft was 16mm but the Boss at the bottom was 25mm and had to go. Decided to make a new post from scratch.



When I removed the compound it was obvious that the post was a press fit with a roll pin to stop rotation



I pressed it out and machined a new one. Luckily I still have my old Sieg SC4. Started with a 40x140mm piece of 12L14 and my little lathe was required to remove most of it. Single pointed the 16mm thread. The 25mm boss is now shorter and does not protrude above the top of the compound allowing the QCTP to sit down on top of the compound.



New Phase II BXA in place


Cheers
Ron

 

[rodw]

Ron, looks great. It amazing how much interest this post about a really simple modification I did ages ago has inspired others to have a go.

 

[timoxx4]

Still yet to do mine. Just waiting on the lathe parts from Hare & Forbes so I can machine the boss down on the compound slide. 12 weeks for the new parts to arrive so I have a bit of a wait.

Damn you Ron you had it easy. lol I wish my boss was like that.

 

[ronboult]

Hi timoxx4

Sorry if your situation is more difficult than mine. If it was my lathe I would remove the compound to see how the actual post is attached under the compound. Then just mount the compound on the mill and mill off the centre boss. I assume the larger boss is flat on top since that is what the original Toolpost mounted on. I wouldn't worry too much over making an irreversible change to your compound because once you mount your QCTP you will never want to go back. After the small boss is gone making a new 16mm post is a breeze
Cheers and goodluck
Ron

 

[canadianhorsepower]

Hi timoxx4

Then just mount the compound on the mill and mill off the centre boss. I assume the larger boss is flat on top since that is what the original T

thats what I had to do on mine
much more rigid also

 

[joco-nz]

Following in Rod's footsteps on my own AL320G.

Started with a big ass bolt, way larger than it needed to be but it did provide some turning experience that for a newbie was/is much needed.



Bolt fits nicely with very little slop.


Length is about bang on and once the washer is on the top it will be perfect.


Next step will be mounting and then we are away. :thumbup:

 

[Quickxb]

Another Al 320G QCTP convert here, thanks to Rod. Only thing that sH^t$ me is that the tool post can only take 1 holder at a time. Sort of defeats the purpose just a tad, referring to the one mentioned in the thread obviously. Anyway thanks Rod it was an exercise worth doing, I can still change tools much faster and have more versatility with what type and size tools I use.