Rocker Style vs. QCTP

[jack620]

Regarding the cost of tool holders- I bought a genuine Aloris QCTP but all my holders are Chinese. They are quite cheap and work just fine. There are no moving parts in the holders for them to screw up!

The beauty of the Aloris style QCTP is that it is QUICK. A common workflow for me when making multiple identical parts:
Turn and face, change to parting tool and make a partial cut, change to chamfer tool and chamfer edges of face and parting cut, change back to parting tool and part off. Extend stock and repeat. That operation would be hell with a standard TP if you had to make more than a couple of parts.

BTW- the Aloris comes with a T-nut.

 

[BaronJ]

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.

Hi Danuzzo,

Note that the tool block was actually a piece of 1" inch thick rolled steel plate that I picked up in the scrap yard I cut it up into three suitable sized pieces. The column, 35 mm diameter in the drawing was a chunk of 40 mm bar, again picked up as scrap. It was originally about 10 inches long. After cutting I got two suitable pieces for the tool post itself. I put a center in each end and turned the outside down between centers, mainly to get rid of the rust and scars on the surface, and to get a smooth uniform surface. After which I drilled a hole right through so that it was a nice fit on the Myford top slide bolt.

The additional step that you will have is to make a proper "T" nut ideally the full width/length of your "T" slot, then make a bolt long enough to be able to get the bottom of the lathe tool above center height.

I've noted the comments about lack of rigidity using the top slide, as of yet I've not had any issues in that respect, but I do feel that it is important to remain within the footprint of the top slide.

Another point of note is that the tool block does not use a clamping slit as you will see from the many other copies of the Norman tool holder. Using a slit is a very bad Idea ! Stick to the split cotter and you won't have any issues with clamping or wobble.

I don't know what the dimension of your lathe top slide are, but I can scale my drawings to suit.

HTH.

 

[BaronJ]

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.

Hi Richard,

I'm a cheapskate I raid my local scrap yard ! However it helps that I've known the family owners for many many years and they do put stuff on one side for me.

There are some metal suppliers around the area but they tend not to be cheap, especially if you want something in particular.

There are also several engineering companies that I have done work for over the years that sometimes help me out.

 

[Richard Hed]

Hi Richard,

I'm a cheapskate I raid my local scrap yard ! However it helps that I've known the family owners for many many years and they do put stuff on one side for me.

There are some metal suppliers around the area but they tend not to be cheap, especially if you want something in particular.

There are also several engineering companies that I have done work for over the years that sometimes help me out.

I've got you beat on "cheap". my skates are made from wood stolen from the forests of Tsar Nicholas before he was executed. I've never used them for fear of wearing them out! Yes, it always helps to know the owner. ONe scrap yard near here was even cheaper than myself, became a millionaire from pinching pennies and then died. Now I don't know the owners at all but it still has good prices for metal.

 

[goldstar31]

I've got you beat on "cheap". my skates are made from wood stolen from the forests of Tsar Nicholas before he was executed. I've never used them for fear of wearing them out! Yes, it always helps to know the owner. ONe scrap yard near here was even cheaper than myself, became a millionaire from pinching pennies and then died. Now I don't know the owners at all but it still has good prices for metal.

What happened to his Holzapffel Ornamental Turing Lathe? Oh, yes he had one with the family crest moulded into the stand

How's that for unusual history?

Norman

 

[awake]

A little late to this conversation ... but I'll jump in anyway.

Not from personal experience: I have read some experienced machinists who say that there are times a rocker tool post can "get into" the cut in ways that a QCTP cannot. An additional consideration is that the rocker tool post may be able to center the cutting forces over the compound, where a QCTP typically has the cutter forces off-center.

From personal experience: I started out with a "4-way" tool holder. I found it an utter pain to get tool height shimmed just right. So, I made a QCTP patterned after a "piston-type Aloris" (B-size, which nicely fits my 12-1/2" swing lathe). Not a beginner's project, probably, but I was not much more than a beginner when I made it, and 10+ years later it continues to work very well for me. All of my tool holders are home-made.

Also from personal experience: When I picked up a 7x14 minilathe, I quickly decided I had to make a mini-QCTP for it. I patterned it after the B-size one I had made many years before, but scaled way down. It is tiny by comparison - but works exceedingly well.

 

[Danuzzo]

Okay. I finally obtained a 2" x 2" x 2.5" piece of mild steel. A machinist that I know just gave it to me.

I may just make one that is very basic and in no form or fashion a quick change.

Baron, looked at the pictures of your toolpost, again, and am having trouble visualizing how the height adjustment works. Would you mind explaining that aspect to me? I really don't need quick change capabilities; but, would like height adjustment instead of using shims.

 

[RonW]

Danuzzo, I see that you are in the USA. There is a company called Metal Supermarkets who have outlets in Canada and the US. Look them up on their website. They have about 80 outlets the last time I looked. I buy all my stock from them cut to size plus a bit for machining. If they don't have stock they'll bring it in for you. Prices are reasonable and no piece is TOO small.
RonW

 

[RonW]

Having just added a size "0" QCTP from Machfit via Banggood in China to my 1949 vintage Myford ML 7 I must say that the results are outstanding. Only thing I had to make was a new securing bolt. I had the four way tool post and somewhere I have an index able four way as well. While they worked for me for years I find the investment of a couple hundred dollars in the post and holders has been well worth it. My only disappointment to date has been the parting tool using carbide inserts. Anything deeper that 1/8" seems to end in a shattered insert. I haven't tried the "blade" version yet. Hopefully now some of my UFOs will get done.
RonW

 

[goldstar31]

Anything deeper that 1/8" seems to end in a shattered insert. I haven't tried the "blade" version yet.
RonW

Do you mean a cut of 1/8th or and a cut finally to 1/8th? ( and then BANG- Bad)

Incidentally, as far as this parting off old chestnut, there are TWO sizes of boring table and BOTH can accept a a GHT inverted rear parting tool- despite the having to 'over hang' a bit.
Oddly, I've just bought a new et of castings/kit to go on my Sieg as the original one is firmly fixed to my Super7B PXF.

 

[BaronJ]

Okay. I finally obtained a 2" x 2" x 2.5" piece of mild steel. A machinist that I know just gave it to me.

I may just make one that is very basic and in no form or fashion a quick change.

Baron, looked at the pictures of your toolpost, again, and am having trouble visualizing how the height adjustment works. Would you mind explaining that aspect to me? I really don't need quick change capabilities; but, would like height adjustment instead of using shims.

Hi Danuzzo,

The height adjustment is the silver colored cap screw that runs vertically through the tool block and presses on the surface below. This allows the tool block to be raised or lowered as needed.

This is also why I mentioned that the tool slot in the block needs to be machined so that the top of the tool slot can be set at center height. The height adjusting screw should be able to raise the tool block enough to accommodate the smallest section tool that you will use. In my case 6 mm. So on mine the range of adjustment for height is 7 mm.

This is a picture of the adjusting screw used in both tool holders, front and rear ones.

 

[Danuzzo]

Thank's, BaronJ. The part I am not fully understanding is whether the base of the tool post rests on the top of the compound, or is it only the adjusting screw that does?

 

[Richard Hed]

Thank's, BaronJ. The part I am not fully understanding is whether the base of the tool post rests on the top of the compound, or is it only the adjusting screw that does?

Yes, now that this has been pointed out, does the height adjusting bolt mar the compound? Probably minor. Anyway, a lathe is to be used not sat in a corner and admired with a bottle of beer, a joint and some porn

 

[BaronJ]

Yes, now that this has been pointed out, does the height adjusting bolt mar the compound? Probably minor. Anyway, a lathe is to be used not sat in a corner and admired with a bottle of beer, a joint and some porn

Now come on Guys, doesn't the pictures of the toolpost and the adjusting screw make it obvious !

This is a picture of the tool post being tried on the existing bolt. The three cap head screws and the ratchet were removed before fitting.

I could have left them but in the interests of getting maximum flat surface area I removed them. The alternative would have been to recess the base of the post.

The part from the top of the red "T" down was simply machined away so that the post is the same diameter all the way along.

This picture shows the tool block sat on the post. At this point the split collet clamp has not been fitted, if you look carefully you can just make out the post through the hole.

The height adjusting screw is sat on the top of the surface below, while I was making a measurement to see how long the brass tip needed to be to get the height range that I wanted with the cap screw backed off a full turn.

The tool block corners were rounded off using a carbide wood router cutter in the mill.

The rear tool post that you can make out at the back is a parting blade holder that has since being replaced by another 35 mm diameter post for a second tool holder.