Quick change insert height

[ColinB]

My 13x40 used lathe came with a quick change tool holder. The lowest position I can get any of the carbide inserts is slightly high (maybe 0.020”), before the tool holders are against the top of my compound slide. Is it possible to machine that much off all of the tool holders (hopefully using my lathe since I don’t own a mill) or some other way to lower the inserts?

 

[Jswain]

Sure, remove all the screws and chuck the tool holders up in a 4 jaw and remove whatever is needed off the bottom.

Or you could take some off the bottom of the tool itself. This might be best if it's only a few and future purchases get the next size smaller ie: 1/2" instead of 5/8". This might be preferably because then all future tool holders do not need to be modified

Or could take some off the bottom of the slot if you use the lathe like a mill

 

[Susquatch]

My 13x40 used lathe came with a quick change tool holder. The lowest position I can get any of the carbide inserts is slightly high (maybe 0.020”), before the tool holders are against the top of my compound slide.

Something is wrong. That BXA tool post should work just fine on a 13" swing. BXA usually works fine on 11 & 12 too.

I'd put some time and effort into figuring out why it's too high. Might be something simple.

Failing that, my preference would be machining 30 thou off the bottom of all your tool holders, not making your tools thinner or deepening the slot. Almost all operations on a lathe benefit from more rigidity not less. The marginal difference favors a shorter tool holder, not a taller slot or a thinner tool.

But start by analysing your tool post system. And checking your true swing - sometimes it's not what the specs say it is.

Just my 2 cents.

 

[phaxtris]

I have a few larger tool holders that I had to mill some amount off the bottom to get them low enough, no problems there

 

[John Conroy]

I have a few 250-202XL tool holders that will accept 3/4" tools instead of the normal 250-202 holders that accept 5/8" tools. The tool slot is .0625" closer to the bottom of the holder. They are the same price so if you are going to buy more tool holders in the future you should look for the XL ones.

Accusize lists them as 250-0201T

https://www.amazon.ca/Accusize-Type201XL-Turning-Facing-0250-0201XL/dp/B01IDLURC8/ref=sr_1_2_sspa?crid=15HCQ9AP6YMPG&dib=eyJ2IjoiMSJ9.xalWnVNkvjNoZxSvD6kSCDCtYZtSFjm7NUArmghxnEMvv6NQgKVQE24jwYvvKJHJKayBrLVxFoX8Tila1HNip8fB-sL-32zisgY_abO7X2BtNgWXGfopLvLhK834rSTyc3Qaai7AGILQBnVRYNYmw3pbPzPiSN3YfWd_3BbGTB5D2V4lzKo2J8eBpj0RY_cACWM1VZ8P3y-G8sQk6PVmtWjrqCwuFs9t8kajgMfqJnCSuOpSeofBTNgWkiOQ37zgvlc-0cGG9VE1Zunn7SpjH_GZMkzE5lwqcE0-mXqjLWw.f8obltPtbfj1NOp4-4F77fv99ek-wvPRkj9I3sC6hwk&dib_tag=se&keywords=bxa%2Btool%2Bholder&qid=1708531716&sprefix=Bxa%2B%2Caps%2C230&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

 

[Susquatch]

I have a few 250-202XL tool holders that will accept 3/4" tools instead of the normal 250-202 holders that accept 5/8" tools.

I was going to suggest. This too. I have a half dozen of the 3/4 Tall ones too. I decided not to because using them with a smaller shank tool leaves a very long screw at the top which reduces rigidity.

No doubt that they will work as you describe, but I think milling off the bottom of holder (for those that have a mill) is a more rigid solution. They are great for those of us with a few 3/4 inch tools.

What I really want to know is why regular bxa doesn't work on this particular lathe.

 

[jorogi]

Rather than fiddling with all your tool holders you might look at the post. It might be over height and if you can remove 0.030" or so off the bottom you would only have the one part to deal with.

 

[Larry_C9]

I had to do that with my tool holders. I do have a mill which makes it fairly easy. They are hard so I had to use good carbide tools to cut them down.

 

[Susquatch]

Rather than fiddling with all your tool holders you might look at the post. It might be over height and if you can remove 0.030" or so off the bottom you would only have the one part to deal with.

Lowering the post doesn't help because the limiting factor is the height of the compound. I wouldn't recommend taking anything off of the compound.

 

[YotaBota]

What make/model is the lathe?

The picture seems to show the tool holder is sitting on the compound, is it?

Edit - Ya, missed the compound comment.

I'd still be interested to know what brand it is.

 

[Susquatch]

What make/model is the lathe?

The picture seems to show the tool holder is sitting on the compound, is it?

I think he said that earlier. Can't go any lower than sitting on the compound.

I still think something else is wrong. If it doesn't become clear soon, I think we need some system measurements. No good reason why a BXA shouldn't fit a 13" throw lathe easy peasy.

 

[L98Fiero]

Rather than fiddling with all your tool holders you might look at the post. It might be over height and if you can remove 0.030" or so off the bottom you would only have the one part to deal with.

Taking material off the tool post isn't going to make a difference, the problem is the distance between the lathe centerline and the top of the compound slide.

 

[phaxtris]

@Susquatch He just has a tall compound, look at how thick it is in that picture

My lathe has a tall compound as well, 5/8 holders sit just a smidge high, everything is fine with a 4 way post, but not with a bxa, I just took it off the bottom of the holders (the insert holders), the xl quick change holders are an option if you haven't already bought the normal ones

 

[L98Fiero]

I think he said that earlier. Can't go any lower than sitting on the compound.

I still think something else is wrong. If it doesn't become clear soon, I think we need some system measurements. No good reason why a BXA shouldn't fit a 13" throw lathe easy peasy.

It depends on your lathe, on my 14" lathe, there was only about 1/8" between the top of the compound and the Accusize 250-202. I still like that Accusize holder though because it's longer and supports the tool closer to the work.

 

[Dabbler]

Boy there is a lot to unpack here.

1) My 12" lathe needs to have an AXA tool holder. that is because the height of the carriage and compound is too high. On some lathes BXA is a little too large, causing fitment problems...

2) For the sake of laughs, try to turn you compound parallel to the Z axis ( the ways). Set up your BXA accordingly. there *might* be enough clearance for your tool holder to go below the end of your compound.

3) The normal use of a turning tool is perpendicular to the ways; Do you have any holders that fit that geometry?

4) I have removed material from the groove the tool sits in to make my height, and I have also removed material from the bottom of the BXA holder, The former is more stable and works fine. This is the way they make the XL holders. The latter works better for some tools.

5) Since you only have a lathe, you can mount your tool in a 4J or 3J chuck, indicate it in, and remove .020 from the bottom of the tool. Taking only .020 - or better yet .040 (to give extra wiggle room) doesn't compromise the rigidity or strength of the tool. This is an interrupted cut, so your cuts have to be very shallow - and, of course, requires multiple tools to accomplish.

 

[DPittman]

I had to do that with my tool holders. I do have a mill which makes it fairly easy. They are hard so I had to use good carbide tools to cut them down.

Yes I found the same and ended up doing some tool holders with a good upright belt sander.

 

[jorogi]

Something is wrong. That BXA tool post should work just fine on a 13" swing. BXA usually works fine on 11 & 12 too.

I really do think that lowering the "effective height" of the QCTP block will work. The height of the cutting edge is predicated on the thickness of the bit, the thickness of the lower half of the bit holder, depth of the lower half of the tool holder, the height of the tool post etc down to bed of the lathe. The cross slide does look thick and non original. If you make any of these components less tall then your tool height is lower. If you reduce the height of the qcth block then you only have the one adjustment to make rather than all you tool holders. If you took it out of the cross slide it would have the same effect but be a slightly bigger job but if it is the cross slide being too tall in the first place it would possibly be the more appropriate way of fixing the issue.

 

[Susquatch]

My 13x40 used lathe came with a quick change tool holder. The lowest position I can get any of the carbide inserts is slightly high (maybe 0.020”), before the tool holders are against the top of my compound slide. Is it possible to machine that much off all of the tool holders (hopefully using my lathe since I don’t own a mill) or some other way to lower the inserts?

If all this recent info is true about the height of your compound, then the best solution (in my humble opinion) is to take 25 thou off the bottom of all your tool holders. Other approaches work too, but this is the most rigid solution.

Deepening the groove works, but leaves the screws long which marginally reduces rigidity by the ratio of their length change to their compressive strength as well as weakening their resistance to lateral flexing.

Taking material off the tools works but leaves the tool shaft less rigid by the ratio of the material strength of the tool.

Taking it off the bottom of the tool holder actually improves rigidity if the tool holder sits on the compound. Otherwise is reduces it slightly but not by as much as other approaches.

Lastly its the easiest thing to do without a mill.

 

[Dabbler]

The tool holder can be held in a 4J chuck and the bottom turned off the 25-30 thou. A fine approach.

I prefer to take off the metal from the tools instead, as this leaves all the QCTP gear as from the factory.

 

[ColinB]

It's about a 25 year old "Made in China" "13x40GEAR HEAD". There is no other branding on the lathe or manual. It is very close to the Enco 110-1351, Busy Bee and Grizzly G4002/3 (but 24/36" ways). The cross-slide and compound appear identical.

There are some items I would like to purchase, but I'm hoping not to need to replace items that came with the lathe.

I measured the axis to ways distance as 6 5/8". There is only 1 3/16" from the axis, to the top of the compound slide. I don't see any practical ways to reduce the height of the compound. There are lubrication points in the way of shaving the top.

The quick change tool holders appear to be able to hold up to a 3/4" tool. My removable tools are 5/8". 1/2" tools or shaving a bit off of the bottom of the tool holder slots wouldn't solve the issue for my parting, knurling or boring bar tool holders.

As I mentioned and I think a few respondents didn't notice on first read, the tool holders are bottoming on the cross-slide. Taking anything of the post won't help me.

Dabbler's points;
2) Yes, I could cut a bit off the end of the "T" nut and hang the tool holders below the compound, but that would only work in certain situations.
3) Yes, but I run into the same problem. I happened to be turning a taper, for the photo.

I think removing a bit from the bottom of each tool holder (+ knurler, parting and boring) is my best bet. I'll use my 4 jaw and take shallow cuts with carbide tooling, since it's an interrupted cut in hard material.