Withdraw-able turning tool adapter for Aloris type toolpost.

[Charles Dolan]

The only thing I really like about Hardinge lathes is the withdraw-able compound which with the reversing clutch makes screwcutting really quick and easy. I am doing a lot of threading on my Graziano at the moment and have decided to adapt the Aloris CA toolpost to allow a similar system to the Hardinge to be used.

I include a sketch which I hope explains my proposal quite clearly and I would appreciate it if any of you can see why this will not work or have any other comments to make about it before I start to cut steel.

Charles

 

[matt_isserstedt]

Sounds great...and a very nice sketch I might add...except you need a tightly-fitted but free-moving sliding way (a conundrum while building any machine!), and have to pay close attention to clearances on the cam so you re-index precisely.

 

[Charles Dolan]

Thanks Matt,

I think that I can fit up the slide adequately but I was a bit concerned about the slide moving under cutting myself. However with an excentric and bush to do the moving they take a lot of acting pressure before slipping I think, and if worst happens it will only move the bit out of cut and not cause any damage.

Charles

 

[Limy Sami]

I suggest you look at the George Thomas design, published in Model Engineer, it looks very similar to your sketch and is proven.
His fits in an ordinary block post but I can't think of any reason the body can't be made to fit the Aloris type.

 

[jim rozen]

Haunt ebay for a bit, investigate hardinge turret
lathe tooling. They made small lever-operated
dovetail tooling which would be a very good starting
point for this project.

Jim

 

[Charles Dolan]

Thanks Jim,

I will give it a go but as usual time is of the esence.

Is anyone having dificulty with the image?

CD.

 

[Limy Sami]

Found this

http://www.hemingwaykits.com/acatalog/Retracting_Tool_Holder.html

 

[L Vanice]

I use the Swiss Multifix internal (AFI) and external (AFE) threading tools on my Clausing 5914 lathe. They are shown in the SPI catalogs. Both are retracting holders to fit the 40 position QC tool posts. The external holder uses a Komet tool bit that just gets sharpened on the top surface. The standard one is a 60 degree vee tool. I ground one of them to make it a 10 TPI square thread cutter to make replacement Hardinge feed screws. The holder is adjustable for the thread helix angle. The internal holder takes round shank tools, and SPI used to sell threading tools with constant form 60 degree ends similar to Bokum boring bars. That is another design that just gets sharpened on the top surface, leaving the angle untouched. The holder has adjustable stroke, so you can match the retraction travel to the internal cutter dimensions and the bore size.

http://www.penntoolco.com/catalog/products/products.cfm?categoryID=1557

Larry

 

[Metalismo]

Looks like a great project that will pay back in time saved. I love that lever on the little tool room lathes! If you make your eccentric so it rotates past center just a bit then the forces of cutting can't move it out. Now why didn't I think of that!?

 

[Keith Krome]

I also cannot view the sketch. What format is the sketch?

 

[dsergison]

your a good sketch artist.

but i dont understand the need?

your in-feeding with the compound if i understand correctly.

so why dont you withdraw with the cross slide? I set my cross slide to 0 just to clear the part. and i wind the compound in a few .001 for each cutting pass. i back the cross slide out some to clear the threads and return it to 0 for each start.

why do you need a retractible tool to do this?

 

[Metalismo]

your a good sketch artist.

but i dont understand the need?

your in-feeding with the compound if i understand correctly.

so why dont you withdraw with the cross slide? I set my cross slide to 0 just to clear the part. and i wind the compound in a few .001 for each cutting pass. i back the cross slide out some to clear the threads and return it to 0 for each start.

why do you need a retractible tool to do this?

Find a toolroom lathe (Hardinge or asian copy) and single point alot of the same threads on it. Then you'll see the need. Monkeying around with the cross slide everytime takes time and in the novices hand invites diasters.

 

[dsergison]

novices monkeying around invites disaster.

im sure a lever is faster. production. i can see it would be handy. good enough reason.

but backing in-out 1 full turn to a 0 I have set has never caused me trouble.

 

[matt_isserstedt]

Monarch has a little setup where you set a hard-stop zero on the cross slide dial by turning a little lever.

So as you crank the cross-slide inwards it will stop at dial = zero on a hard internal stop.

When chasing, back out to wherever comfortable, reverse the carriage, and crank in until you touch the stop. Very quick, and a nicely thought-out feature IMHO. It takes about 1/2 minute of fiddling with it to get it set right...but saves 5x that when chasing parts.

 

[rodjava]

I had the same thing in mind and was planning to build a "Retractable tool holder for screwcutting" by Geo Thomas.

Howard/aka Stealth Pilot from another forum was generous enough to send me scaned pics for building the project from the book titled, The model engineers workshop manual by Geo
H. Thomas.

Here is a link to one already built by gadgetbuilder: http://www.gadgetbuilder.com/ToolHolders.html

I can email you the files if you need them. I can't take the credit for it. Thank Stealth Pilot.

Rod
San Francisco

 

[Errol]

Rod:

I would also be interested in looking at the files. Although I need anoter project like a bass needs a bicycle.

 

[Charles Dolan]

Thank you again Sami.
Larry, the web page you link is under maintenance but I would certainly be gratefull if you could let me know of a dealer who would sell items you speak of.
Dsergison I am perfectly familiar with the use of the cross slide to withdraw the tool but when using the Hardinge retractable I cut threads literaly 5 time faster. As matt points out it is not so much the withdrawing that speeds things up but rather re-zeroing without thinking. A positive stop for the cross slide was something else I was thinking about.
Rodjava thanks for the offer of the scans but it is time I bought the Model Engineering book myself.

Again I am obliged to everybody for their comments.

Charles

 

[L Vanice]

...Larry, the web page you link is under maintenance but I would certainly be gratefull if you could let me know of a dealer who would sell items you speak of....

http://www.penntoolco.com/catalog/products/products.cfm?categoryID=1557

Larry

 

[Spin Doctor]

The other thing that makes the Hardinge so fast on cutting threads is not having to disengage and re-engage the half nut every time. Granted on long threads you do loose time running the leadscrew in reverse but a lot of the time you can kick it into high range.

 

[J-Head]

Nice drawing Charles.

I have been thinking about making one of these myself. The home brew on in the above link looks good but I would like to see the drawings because I can't quite tell how the eccentric works.

Does anyone know how much the SPI ones are, I see they don't have the price listed. The home brew one actually looks better with the dovetail slide fo better support.