Withdraw-able turning tool adapter for Aloris type toolpost.

[wesg]

From an old '92 catalog I have:

Depending on toolpost size, between $600 and $900 for the external model. $650-$1k for the internal.

 

[precision tools]

Metal Lathe Accessories has a casting kit for a quick retracting toolpost for threading. It is a dedicated toolpost, but might provide food for thought. As with all of Andy Loftquist's kits, it is well thought out with well drawn, easy to follow plans and excellent castings.

http://www.statecollegecentral.com/metallathe/MLA16D.html

 

[ztarum]

I have both of the multifix holders, which I got for a good price on ebay years ago. They are nice for small threading in reasonable material, but are not very stiff. If you get too aggressive deflection is a problem. I think a sliding dovetail design is the way to go.

 

[Limy Sami]

At say $1000 plus apiece, those multifix holders have got to do A LOT of threads.

 

[L Vanice]

At say $1000 plus apiece, those multifix holders have got to do A LOT of threads.

They cost less when I got mine around 1980, and they were worth every penny.

Larry

 

[Charles Dolan]

I have just finished the tool holder, it worked out very much as I thought but I moved the lever to the right to keep the hand away from the chuck.

Charles.

 

[dsergison]

very nice..

does it have a gib on the bottom of the dovetail?

 

[Charles Dolan]

Yes it does, a stip of 3/16" cupro nickel. It is on the bottom because I didn't want the screws to intefere with clearing the chips. (Or perhaps I forgot which side to mill the allowance on!).

Charles

 

[The real Leigh]

Aloris #8 or #88 threading tool

Buy the #CA-8 or #CA-88 threading tool.

Mount the cutter in the upper position (as designed), run the lathe backwards and thread toward the tailstock. No need to worry about withdrawing the tool.

Works great.

- Leigh

 

[Charles Dolan]

Leigh,
How do you get it back to the begining of the cut without with drawing the tool from the helix?
CD.

 

[The real Leigh]

How do you get it back to the begining of the cut without with drawing the tool from the helix?

Hi Charles,

Just back out the compound, move the tool back to the beginning (toward the headstock) and feed in as desired to the starting point.

I always start the thread (at the shoulder) with a small undercut, so the tool has a resting point before it starts threading.

My compound is set square to the work, not at 29+ degrees.

The threading dial works as usual for synchronizing the cuts.

One major advantage of the #8 (or #88) tool is a provision for canting the cutter at an angle to match the helix angle of the thread, so no more dragging the tool heal on the thread, or having to severely undercut the tool for clearance, or grinding different tools for different threads.

- Leigh

 

[awake]

Charles, if yours is an original design, any chance that you will be publishing the plans?

 

[Charles Dolan]

Awake,

I posted the same photos in the Graziano forum and there has been some interest there. I very rarely make full plans for my projects which usually just grow out of need and available materials. This is in fact a very simple device but it does require some precise fitting of the slide and the eccentric. Give me a few days and perhaps I will produce a drawing.

Charles.

 

[Charles Dolan]

Here are a couple of shots of the innards which I think should make a drawing unnecessary.

Charles

 

[rodjava]

Charles,
Is it resonable to think that the bit is retracted when the handle is in vertical position? When you pull down, the bit is extended?

I'm building the tool in my mind before the actual build.


Nice work!

Rod
San Francisco

 

[richard newman]

Very cool gizmo, look like it could save lots of time. And one less thing to have to pay attention to at a critical moment.

But what I'd really like to see is some kind of stop/throw-out that wouldautomatically retract the tool at the end of the thread, eliminating the need to have a clearance groove there. I've read that experienced operators can do this manually, but it seems potentially disastrous, so I haven't tried it.

 

[Charles Dolan]

Rod and Richard,

the tool is retracted when pulled down and back, to do otherwise seems counter intuitive to me. You can fabricate a self acting screwing machine if you want but it is a very long row to hoe. For my mind just eliminating the concentration needed to return the cross feed index to the zero acurately each time more than halves the time per pass. depending on how fast you run your lathe it is perfectly possible to end a thread in a small drilled hole every time.

Charles.

 

[dp]

Evan Williams' cross slide threading stop takes care of re-zeroing the cross slide problem:

http://metalshopborealis.ca/tstop/tstop.htm

 

[dp]

Rod and Richard,

the tool is retracted when pulled down and back, to do otherwise seems counter intuitive to me.

Charles.

Does the cam action lock overcenter to prevent pushback?

dp

 

[Charles Dolan]

D.P.

The threading stop you show will take care of the problem partly. It is still necessary to break the half nuts or stop the lathe and reverse it. My lathe has forward neutral and reverse instantaneous clutches and with the withdrawing tool this makes for the fastest threading procedure.

When the rolling block is rotated forward as far as the handle is allowed by the flank of the slot, the eccentric pin and connecting rod is placed to be a few degrees over center and therefore a few thousands below the center line of the block where because of the great moment of leverage now in play it firmly resists the slide moving backwards under cutting force.

Charles