Lathe Compound

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asallwey
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Location: N. Virginia

Re: Lathe Compound

Post by asallwey »

Other than for taper turning or during single pointing threads there's good logical arguments for removing the top slide completely and using a solid spacer block to mount the qctp to it.
I have a solid toolpost that came with my machine and I do use it. I also got the QC holder from them at the same time, just didn't use it much the first few years. But it had a bend which made turning the handle challenging. I've always wanted to attack it (replacement screw unavailable), and this Winter the idea moved to the front of my brain, so I'm doing something about it. I figured some folks here would have good suggestions, and it's a good place to begin my project. So I'm acting on the suggestions and moving forward. I appreciate your help.

Alex
pete
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Re: Lathe Compound

Post by pete »

That G. Thomas book should help then. There were few parts he didn't redesign and build for his Super 7 lathes top slide that are probably considered pretty good to start with. He even added an opposite handed feed screw and used a couple of gears to off set the operating handle for more clearance between the cross slide hand wheel and tail stock when the top slide was swung to different positions. Then added a lever retraction much like Hardinge uses while single pointing threads. http://www.hemingwaykits.com/acatalog/G ... rd_S7.html Make sure you read his thoughts about pinning the gib in place and adding a simple slide lock.
asallwey
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Location: N. Virginia

Re: Lathe Compound

Post by asallwey »

I think I'll hold off on the compound until I get the book and do some reading.

Thanks again.
asallwey
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Location: N. Virginia

Re: Lathe Compound

Post by asallwey »

Pete,

The book arrived yesterday. There sure is a lot of interesting material beyond my initial area. This will take a little study to see if I can make use of any ideas. Of course, seeing something that would help is not the same as implementing, or machining, the parts. But I'll see what I can do. I appreciate the lead, this is the first book in quite a while, on machining, that I've read. What I like about reading is that my mind automatically brings in the tooling I have when I look at how a part is described. On Youtube, the good guys always have the right tool, sharpened to the nth degree, all play and/or misalignment taken out, the sequence of work perfect, and 9.9 of 10 times, the finished product is great. My equipment, big and small, almost always leads me on small tangents: to sharpen this, align that, etc, etc. etc.

Thanks again,

Alex
pete
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Re: Lathe Compound

Post by pete »

Glad your enjoying that already Alex. As I've said here in the past, that's the very best book I own and it's taught me more than just about everything else I have combined. Yes the majority of the designs are fairly specific to the Myford lathes. But if you've got the skills and tooling to make the more complex items, you have enough to redesign and modify to fit what you happen to own. I've had my copy probably for over 20 yrs now and still refer to it. As good as YT can be sometimes, it still can't fully cover any subject in the detail that a good reference book can. While I do own and use them most times, in my opinion G.H.T. also has some real valid points about his preference for the almost now standard OEM 4 position tool post over any qctp no matter how good it might be.

That GHT book also had a great deal to do with my final choice for the last lathe I purchased and what I wasn't willing to do without. His other book Workshop Techniques is also pretty good and there is a lot of very good methods to learn from. But it's all specific to I think 4 different lathe accessories and tools. One of them would be a very versatile high speed instrument type drill press, that can do staking of watch/clock parts, tapping, maintain alignment during number stamping etc. Hemingway Kit's in the U.K. sell that book and the castings. http://www.hemingwaykits.com/acatalog/U ... _Tool.html There is sort of a companion book written by another author (J.A. Radford) for a few items Thomas mentions and made his own design changes to in your book, but doesn't detail with any drawings for logical reasons.
https://www.teepublishing.co.uk/books/l ... our-lathe/ That ball turning attachment being one of them. It's also pretty good, but still not up to what you just bought.
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liveaboard
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Re: Lathe Compound

Post by liveaboard »

I use my compound quite a bit; the graduated dial is very useful for finding depth of a bore or length of a shoulder. Of course it will never be quite in line, so final cuts are made with a moving carriage.
I also find it handy for threading, which is a fairly common job for me.
Sometimes I remove it, but mostly it stays in it's place.
bjt3141
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Joined: Tue May 18, 2021 9:31 pm

Re: Lathe Compound

Post by bjt3141 »

From an enthusiastic newbie:

The idea of a rigid, solid QCTP riser to replace the compound on a 9x20 is logical and appealing, but leaves me with a question that might be obvious to others.

All the plans I have seen fix the QCTP squared against the ways and the chuck. This is perfect for turning and facing operations, but what does one do about facing into a shoulder with a HSS tool, when you need to set the compound at an angle?

As I type this, it occurs to me that most of the articles and videos I have seen feature carbide insert tooling, and maybe there is an angled holder that gets into the shoulder?

See? A newbie for sure.
curtis cutter
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Re: Lathe Compound

Post by curtis cutter »

bjt3141 wrote: Wed May 19, 2021 9:07 am From an enthusiastic newbie:

The idea of a rigid, solid QCTP riser to replace the compound on a 9x20 is logical and appealing, but leaves me with a question that might be obvious to others.

All the plans I have seen fix the QCTP squared against the ways and the chuck. This is perfect for turning and facing operations, but what does one do about facing into a shoulder with a HSS tool, when you need to set the compound at an angle?

As I type this, it occurs to me that most of the articles and videos I have seen feature carbide insert tooling, and maybe there is an angled holder that gets into the shoulder?

See? A newbie for sure.
I move my QCTP all around as I need it. I can always square it up again if necessary.

As for the insert tooling, there are a number of people here who will advise you to learn to grind your own tooling to perform a task. It is a highly valuable educational experience. You are not locked into what a manufacturer makes for you to use.
Gregg
Just let go of it, it will eventually unplug itself.
Russ Hanscom
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Location: Farmington, NM

Re: Lathe Compound

Post by Russ Hanscom »

Nothing says that the QCTP has to be squared with anything. Yes, most convenient for most operations to have it squared to the ways, but it only takes seconds to change it to a more convenient setting for a particular task.
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NP317
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Re: Lathe Compound

Post by NP317 »

Curtis Cutter said:
"I move my QCTP all around as I need it. I can always square it up again if necessary."

I do the same. Whatever position works best for a cut is what I do.
I often mount tools at an angle in the QCTP as needed, and I have no fear of changing the post angle.
RussN
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Harold_V
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Post by Harold_V »

In my opinion, the only reason for a quick change being installed square with the spindle is for use of a parting tool, one that is made specifically for that purpose and does not allow random setting of the blade (which MUST be set square with the cut). Aside from that, there is no reason why a QC can't be placed at random angles.

That said, I do not use a QC. As I specialized in small work when I was running my machines for profit, I, by far, preferred a square block. I use an O.K. Rubber Welders block, which has detents @ 15°increments, plus individual finer detents that permit 3° spacing. I can index my block faster than a QC can be changed, which is ultra critical when taking small cuts with multiple tools repeatedly. YMMV. :wink:

H
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