Rocker Style vs. QCTP

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Danuzzo

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My lathe, a Select 816B, came with rocker style tool post and holders (see this thread for lathe details: Select 816 B Lathe Acquired

Have various holders, including a boring bar. So far, I have only used the left hand, right hand, and cut-off holders. To me, they seem plenty rigid. I did do some cut-offs of 1" diameter mild steel yesterday, and when used at a low speed (backgear), no issues of chatter. I was wondering if I were to try a QCTP, would it have anymore rigidity; rigidity that I don't know I am missing at this point? Ignorance may be bliss :) .

I know many loathe the lantern rocker style tool posts; I don't mind them. Yes, center may be more difficult to find and it is more time consuming to set up; but, I have more time than money to spend. So, is there a significance in rigidity between the rocker style and the QCTP. Of course, I may not want too much rigidity, as I don't want to damage my compound or related parts if I get a significant catch.

Now, if a QCTP is in order, the sizes that will fit my lathe are either the OXA or the AXA, with the OXA I am looking at being significantly less expensive on a particular site. If I understand correctly, the OXA is close to 1.75" square, while the AXA is around 2.5". The compound t slot on my lathe is such that the OXA will not be near the edge of the compound, while the AXA will be right at the edge. The base of the compound where the base of the QCTP would mate is slightly over .90" to centerline. Here is a photo of the tool post and compound area.

Opinions welcome.
 

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kuhncw

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The AXA size QTCP should be a good fit for your lathe and I feel you would really enjoy using one. Changing tools is quick of course, but you can also remove the tool in order to get it out of the way for inspection or to take a measurement. When you put the tool back, it goes right in to position.

Chuck
 

BaronJ

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Hi Danuzzo,

If you fancy a project why not make your own tool post !

This is a picture of mine, its a "Norman Patent" one as used by Rolls Royce in their development workshops. I have some drawings for it as well, but you might have to adjust the size to suit your lathe.

25-09-2018-006.JPG
25-09-2018-007.JPG

I use this on my Myford lathe and also have one as a rear parting blade tool post. The holders are interchangeable so I can use either. In the first picture the silver cap head screw on the top is the height adjustment and in the bottom picture the cap head screw on the side is the locking screw. It only takes about 1/2 a turn from locked to free.

I have a complete build log on this.
 

goldstar31

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I can understand the use if the Norman tool post but but arguably neither have the rigisity which comes from removing the usually little used top slide.

I've been 'playing about' with a QCTP on my present Myford and wonder whether it has 'any cons'.
Some of the best of the British(?) model engineers have their versions -- of not having the top slide.
Jack Radford- a New Zealamder produced a tool post- probably beyod the skills of the average worker- amd descrribed it in his fantastic 'Improvements and Accessories for your lathe'. Tom D Walshaw wring as Tubal Cain pruced what can be rightly described as his Gibraltar tool post. I have the casting unmachined but- ye Gods, it's heavy lump!. I never really got into what the Late John Stevenson MBE- LPL did but but he threw the top slide away. Geo Thomas did his rathet 4 way tool post but 'went off the rear end of the Myford saddle with the rear parting tool post-- and then someone almost as inventive, removed one lade and added an inverted 'normal' lathe tool which gave FIVE lathe tools and ONE rear parting tool. With a Myford ML10, I got a solid lump wit a single slot for a lathe tool.

BUT- if you haven't fallen asleep, ther is pr was Martin Cleeve. He hadn't a milling machine and simply cut up 3 bits of mild steel plate and wrote it all up in Model Engineer- describing how there was also 4 positions for lathe tools-- but, but he also took 3 bits of plate which he bolted together with homemade bolts and stuck it on the rear end( ouch) of his much modified ML7.

Ah but he went one sep further- and made a swing tool for boring and then improved it by adding a cam instead of a plain but of round-- and made it into 'a retracting tool post'

I never quite got to that bit but I have his boring swing tool- made from fabricated bits.

Yer pays yer money and yer makes yer choice!
 

Richard Hed

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My lathe, a Select 816B, came with rocker style tool post and holders (see this thread for lathe details: Select 816 B Lathe Acquired

Have various holders, including a boring bar. So far, I have only used the left hand, right hand, and cut-off holders. To me, they seem plenty rigid. I did do some cut-offs of 1" diameter mild steel yesterday, and when used at a low speed (backgear), no issues of chatter. I was wondering if I were to try a QCTP, would it have anymore rigidity; rigidity that I don't know I am missing at this point? Ignorance may be bliss :) .

I know many loathe the lantern rocker style tool posts; I don't mind them. Yes, center may be more difficult to find and it is more time consuming to set up; but, I have more time than money to spend. So, is there a significance in rigidity between the rocker style and the QCTP. Of course, I may not want too much rigidity, as I don't want to damage my compound or related parts if I get a significant catch.

Now, if a QCTP is in order, the sizes that will fit my lathe are either the OXA or the AXA, with the OXA I am looking at being significantly less expensive on a particular site. If I understand correctly, the OXA is close to 1.75" square, while the AXA is around 2.5". The compound t slot on my lathe is such that the OXA will not be near the edge of the compound, while the AXA will be right at the edge. The base of the compound where the base of the QCTP would mate is slightly over .90" to centerline. Here is a photo of the tool post and compound area.

Opinions welcome.
Can you give us a better shot of the compound. Your photo is of the tail stock mostly.
 

Richard Hed

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Hi Danuzzo,

If you fancy a project why not make your own tool post !

This is a picture of mine, its a "Norman Patent" one as used by Rolls Royce in their development workshops. I have some drawings for it as well, but you might have to adjust the size to suit your lathe.

View attachment 118328View attachment 118329
I use this on my Myford lathe and also have one as a rear parting blade tool post. The holders are interchangeable so I can use either. In the first picture the silver cap head screw on the top is the height adjustment and in the bottom picture the cap head screw on the side is the locking screw. It only takes about 1/2 a turn from locked to free.

I have a complete build log on this.
This doesn't look like a quick change. But I am interested in the drawings. If they can help me out, I can build it.
 

danallen

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I am a fan of quick change tool posts. I have an A size on my 9" South Bend. It can get in the way when turning small parts with a live center. The obvious benefits are having multiple tools preset on center and being able to reposition or remove the tool post without losing tool center.
 

BaronJ

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This doesn't look like a quick change. But I am interested in the drawings. If they can help me out, I can build it.
Hi Richard,

It isn't in the conventional sense and I don't have to keep buying expensive tool holders.

I got rid of the Dickson QCTP that I had, far too expensive to keep buying tool holders for it ! So I made the "Norman Patent" one and wish that I'd made it years ago. It is just as convenient as a conventional QCTP and in a lot of ways much better.

Yes there is a technique to getting the best out of it, but it would be very hard to find better value for money ! Lets be honest, I'm a hobbyist not a production machinist nor a tool snob.
 

Richard Hed

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Here you go.
Ah yes, the fabulous rocker. I had a 1918 SB which had one. Glad to not have to use it. My suggestion: get a QCTH if you can get a cheap Chinese one which you will have to build a "T" bolt to hold it on your compound. you could also try Baron's tool holder. I thimk I am going to try that after looking at his drawings. I thimk any tool holder is better than a rocker. Just my opinion. I see many peeps using them on utub doing fine work.
 

BaronJ

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Hi Guys,

This is my drawing ! If you use this check the dimensions carefully, its a while since I made one and I don't remember if I altered the split cotter size from 12 mm to 14 mm. It sticks in my mind that the original bolt through the split cotter was M5 and I changed it to M6 so that all the cap head screws used the same size Allen key.

Norman-001.jpeg


Danuzzo,

If you measure up the "T" slot I can do a drawing of it for you.
 

Richard Hed

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Hi Danuzzo,

A Norman Patent tool post would go on there perfectly ! You would have to make a proper "T" nut base though, but the rest is quite straightforward.
I like what I see in your photos of your own build of a tool holder. However, I am not sure whether or not I would like to try them. Could you send me the drawings? I use quick change tools but am always on the look out for something better.
 

Richard Hed

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Hi Guys,

This is my drawing ! If you use this check the dimensions carefully, its a while since I made one and I don't remember if I altered the split cotter size from 12 mm to 14 mm. It sticks in my mind that the original bolt through the split cotter was M5 and I changed it to M6 so that all the cap head screws used the same size Allen key.

View attachment 118345

Danuzzo,

If you measure up the "T" slot I can do a drawing of it for you.
Whoa, PSYCHIC!
 

goldstar31

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Hmmm! Clears throat and confesses:)

I've just taken off that awful QCTP and substituted an original Myford 4 tool - too post.:mad::mad:

Well, it's like this, your honour- I lost a lot of small lathe tools a couple of years or so ago in two storms and each time that I'm making another bit for for this 'displacement therapy Worden tool and cutter grinder, I get a longing for my lost tools to do the jobs.:D

Such is life.
Apart from a few nuts and bolts, grub screws and that rusty heap of metal that survived the storms, the cost is NOTHING for the tooling.
 

Danuzzo

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Thank's, Baron. Looks like something I would like to make. That is very generous of you to offer to make a drawing for me; but, it is not necessary at this time.

I have made a tool post, but not quick change, for a 6" Craftsman I once had. I wanted to make another, larger, for the current lathe; however, I stumbled into issues locating the 2" square steel material. I checked online, and the price of shipping was more than the steel. I will keep looking, and I will check with a machinist next week to see if he has a small chunk to sell. If I can get the materials at a reasonable price, I will make one.
 

Richard Hed

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Thank's, Baron. Looks like something I would like to make. That is very generous of you to offer to make a drawing for me; but, it is not necessary at this time.

I have made a tool post, but not quick change, for a 6" Craftsman I once had. I wanted to make another, larger, for the current lathe; however, I stumbled into issues locating the 2" square steel material. I checked online, and the price of shipping was more than the steel. I will keep looking, and I will check with a machinist next week to see if he has a small chunk to sell. If I can get the materials at a reasonable price, I will make one.
Whereever do you live? I live in a small town and there are at least 3 metal yards within 5 miles of where I live. I can get most any metal for very cheap. Of course if you are looking for very special metal, then buy on line.
 

Danuzzo

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We have 1 metal supplier in the area. Aluminum round stock is easily available there by the foot at very reasonable prices. Problem is, for the steel 2" stock, I had to buy a minimum around 10' (can't recall exact length) length. We do have a scrap yard where I have made some nice finds; however, I have not found any scrap 2" square steel, and, I have been looking for a while now.
 

Richard Hed

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We have 1 metal supplier in the area. Aluminum round stock is easily available there by the foot at very reasonable prices. Problem is, for the steel 2" stock, I had to buy a minimum around 10' (can't recall exact length) length. We do have a scrap yard where I have made some nice finds; however, I have not found any scrap 2" square steel, and, I have been looking for a while now.
I found some really nice round stock : it's the arm in a hydraulic system. You might be able to find a 3" round and cut it down or a 4" piece. I bought over kill as the 3" piece was about 4' long--but I have already cut off about 18" for projects. My biggest problem is that my 4" 3jaw is too small for "inside" jaw use so I switch out to "outside" jaws which gives me the room but only a small bit to chuck up on. Last resort: 4 jaw.

The stock is very high quality stuff and also easy to machine. Not sure when or where the stuff comes from.
 

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