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Quick Change Tool Post Size For 12" Lathe

Armourer

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#1
Well I finally got some money saved up for a quick change tool post, but before I order I thought I better get your guys second opinion on it. I was sold on a BXA wedge post, but doing a little research found that it may be too large for my lathe. Is that true? Would I be better with a AXA Wedge style? Thanks for the help.
BTW I will be getting it off eBay, is it ok to post links to the ones I am looking at for your opinions?
 

Bob Korves

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#4
The swing of the lathe has nothing to do with what size tool post your lathe takes, even though some sellers seem to think so. The thing that matters is the height from the top of the compound rest to the spindle center. You can use a center in the tailstock to measure the distance. Shars and Dorian show the actual dimensions so you can see which one will fit your needs best. It takes some thinking and figuring, but don't get a tool post that fits marginally on YOUR lathe.
 

tq60

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#5
12 inch is a tricky spot as different brands have different styles of carriages resulting in a wider array of heights.

You want the biggest one that will fit and still allow the tool to adjust properly.

If your lathe is a known model the manufacturer of tool post can suggest proper one.

Otherwise get your carriage close to the Chuck and measure from to of Carriage to center of chuck.

Take a photo and write the dimension down then contact a dealer to see what they suggest and we suggest first set something like the import aloris copies then ebay for add ons.



Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 

Groundhog

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#7
I just got my 12x36 lathe a few months ago. I added a BXA wedge tool post and works just fine. However, I can't help but wonder if I would have been happier with the AXA (it would have fit as well) because of less interference issues as well as tool costs.
In the end I've decided that the added rigidity of the BXA offsets any benefits of the smaller tool post, at least for me.
 

12bolts

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#8
If only the AXA fits, then thats what you're stuck with. But if you have room for a BXA then get that. You can't put bigger tooling in a smaller post

Cheers Phil
 

firestopper

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#9
I would also consider the added rigidness of the BXA vs AXA. I have a 14"x40" and run CXA with no issues and love the rigidness the heaver tooling provides.
Post any links of the tooling your considering.
 

ndnchf

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#10
I have a Phase II AXA on my 12" Atlas and it works great. It is much more rigid than the old lantern post. I'm very pleased with it.

Steve%20Atlas_zps9p21pgtw.jpg
 

pdentrem

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#11
I purchased a AXA for my Atlas 10" and when I sold it and bought a 1340, I simply moved it over. On my lathe a BXA would be border line. The height of the top slide is going to call out which toolpost you can use as others have stated.
Pierre
 

Tozguy

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#12
Bob nailed it in post no. 4

My 12x36 gap bed lathe is 1.22'' from top of compound to axis of spindle. BXA size is best for me.
 

ndnchf

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#13
I just measured my 12 Atlas, 101.7403, it's 1.22" also. The AXA is what I use.
 

Bob Korves

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#14
Another issue is what size tools you normally used in your holders. A BXA might hold 5/8" tools, or even 3/4" tools with an oversize holder, but what if you typically use 1/4" tools? What about your boring bar setups and cutoff setups? There is more to this than what it initially seems to be, and what works for one person might not work at all for another. There is also some overlap, as noted, so it is worth looking at how all your anticipated tooling setups will work on YOUR lathe with YOUR tooling doing YOUR kind of work. Saying a 12" lathe takes a BXA, or an AXA, and no others, and leaving it at that, is like wearing blinders on purpose...
 

electrosteam

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#15
There are a couple of other issues that could influence you.
Just consider them before you make your choice.

Some topslides have holes drilled in them to enable pin location of the toolpost at 0 and 90 degrees.
On my Harrison M250 (Clausing something), the BXA does not fully cover the holes used by the original Dicksons toolpost.
Every time the BXA is rotated, these holes are uncovered, then covered, with the inevitable result of swarf/lubricant being dragged under the toolpost with subsequent scarring and looseness.
This is a real problem not anticipated and I will have to deal with it in some way.

Then there is tool reach.
Most of these toolposts expect tools to be inserts carried on a holder that is then mounted into the toolpost adapter.
But, if you try to use HSS tools directly in the toolpost adapter, the cutting edge may not reach out far enough tp prevent the topslide itself coming into contact with the job or chuck, or the topslide contacting the tailstock on small diameter jobs.

John
 

Buffalo20

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#16
When I bought my QCTP tool post from Dorian, they told me there is no additional rigidity gained by going to a BXA vs AXA QCTP, they said the weak point is the lathe compound and carriage, both will flex long before any of the tool post will. The real benefit is the ability to use larger tools, without modifying the tool blocks. I have open many AXA blocks out to hold 5/8" and 3/4" shanked tools, probably buying the larger larger size, might have been the easier way to go. Not better, but easier.
 

Armourer

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#17
Oh boy you guys brought up a bunch of stuff I hadn't considered! Thanks, will make me go back to the drawing board. As far as tooling the biggest bits I have are 1/2" and don't own anything smaller then 3/8". The top of the cross slide to the centre of the headstock on the lathe is 1.250"
This is the one I am thinking about getting http://www.ebay.ca/itm/281990113312?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
It says it suitable for a lathe swing of 10-15" with a measurement from the cross slide to spindle centre from .7-2.2 so it should work ok? Or possible to large? Thanks again
 

Mikesal

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#18
This has been interesting reading. I have a Enco 13x40 lathe & didn't have a good feel on which size of new tool post to buy for it....wound up with the bxa 200 size.....seems a little big, but we'll see after I get the foot machined to fit my T slot (which is huge by comparison to the original post foot that came with the lathe). I just received the post set a couple days ago & will be working on it this week.
Mike S
 

Tozguy

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#19
Oh boy you guys brought up a bunch of stuff I hadn't considered! Thanks, will make me go back to the drawing board. As far as tooling the biggest bits I have are 1/2" and don't own anything smaller then 3/8". The top of the cross slide to the centre of the headstock on the lathe is 1.250"
This is the one I am thinking about getting http://www.ebay.ca/itm/281990113312?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
It says it suitable for a lathe swing of 10-15" with a measurement from the cross slide to spindle centre from .7-2.2 so it should work ok? Or possible to large? Thanks again
Armourer, why would it be too large?
 
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12bolts

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#20
The actual size of the post means that you cant get the tool down below centre. So depending on the physical height of your cross slide and compound a BXA may or may not be suitable. As Bob said earlier, its not the swing of your lathe, its what you can pass over your saddle.

Cheers Phil
 

TakeDeadAim

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#21
I agree with Bob regarding the height of the toolholder in relation to the centerline of the lathe as measured off the top of the cross slide/compound where the holder mounts. I have a 13x36 lathe and use a BXA/200 size holder. One thing to consider is the use of a larger tool holder will allow you to use larger tool holders. The 200 size allows the use of 5/8" square tool holders. I find a wider variety of both tool holders and inserts available for the larger sizes and in fact have bought some 3/4" holders and milled the shanks to allow me to get the insert I wanted.

Shars tool does have drawings of the tool holders on their site and I do have some of their holders which seem to work quite well.
 

Tozguy

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#22
Why would it be too large?
The question was for Armourer, who knows the critical dimension on his lathe to be 1.25'' and the dimensions of the tool holder he is considering. Just wondering why he still thinks it might be too large.
 

pdentrem

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#23
IMG_1193.JPG
Just out of interest I took this picture showing my AXA on my Jet BDB1340 clone.
Pierre