What's new
What's new

Making new draw bar

AlfaGTA

Diamond
Joined
Dec 13, 2002
Location
Benicia California USA
So some time back i offered and sold my late high speed head.
Been some time getting it all together as the shipping is a bit difficult.
This week i had everything ready to start packing in a crate, wanted to fit an extra collet i owned into the spindle for protection....
Surprise! turns out this head was fitted with a male threaded draw bar (5/8-11)This would work for NMTB 40 holders but not the std. Deckel collets.
I was unaware of this as i had never used this head myself, and i had told the buyer that the head would accept std. Deckel #40 collets.....

Solution was to make a new draw bar that would take the 20x2.0 buttress thread of the normal Deckel tooling.
Most here was lathe work so not really "Deckel" but i thought some might enjoy some details on doing this job.

I set up a piece of material in a 5-c collet setup on the lathe. Material is 1" OD. ETD 150. This material has a hardness of 30-35 Rch.
Turned the end and bored it for the minor diameter of the collet thread. Back relieved the bore for thread clearance, then i needed to address the internal 20x2.0 Buttress thread....
I have inserts that would work for this job, bad news is the boring bar that can hold these is way too big to enter the bore on the part...need another plan.
Doug out a small boring bar with a square hole at the end (3/16") and a proper piece of high speed steel.

Set up the bar in a clamp on a little universal tool vise on my surface grinder....Seting it up in the bar helps (i believe) in getting an accurate tool as i won't have to remove it from the bar to set it up to cut the threads......

full


full


Then i needed to align the tool to get the thread form aligned to the axis of the part....
I did this by employing a good genuine Deckel collet, Using a 1" collet i slid it over the stock (was snug) and aligned my cutting tool with the back side of the collet thread.

full


Once set to height and aligned i proceeded to cut the thread using the same collet as a gauge.....

full

full


Threads finished part turned around and the opposite end threaded for the adjusting collar and turned for the hex at the end.
More to follow......
 
Thanks for taking the time to describe this Ross, always a pleasure to follow.

Wondering...why hex at the top of the drawbar and not the good old deckel square?

BR,
Thanos
 
Looks like it came from the Deckel factory. Beautifully done.

What is the dividing head thingy in the vise? Looks light/easy to setup up.
 
Thanks for posting!!! I'm going to copy this when I make a deckel drawbar for the horizontal...as far as the buttress thread goes!

Jeff in long beach
 
Wondering...why hex at the top of the drawbar and not the good old deckel square?

BR,
Thanos
Thanos:
The late manual machines are fitted with a different draw bar.
There is a threaded collar that threads on to the draw bar and sets the end play That collar’s upper face has two hardened dowels sticking out
There is a second part that engages the hex on the end is the draw bar and is face drilled to fit the dowels.
You adjust the end play in the draw bar And set the adjustment by locking the upper collar to the dowels in the lower piece.
The top side of the upper collar has a 10 mm internal hex to fit the std right angle hex key.
The upper collar is retained by a snap ring.
One additional feature is that there is a spring loaded plunger inside the 10mm hex. This is a safety that prevents the hex key remaining in the draw bar.

The factory setup i removed had the late setup, so I copied the top end of the draw bar and used the factory parts.

This setup tales the place of the collar and taper pin to adjust the draw bar end float.
Also provides the safety feature described above.
Cheers Ross
 
What is the dividing head thingy in the vise? Looks light/easy to setup up.
That is a Hardinge 5-c collet index fixture. Nice for quick work.
Has 24 index points. No masking , but the back ring is marked so it’s easy to count spaces.
See these often on E-bay.
Cheers Ross
 
Last edited:
Thanos:
The late manual machines are fitted with a different draw bar
I had the same question and with this, even if difficult to visualize in my mind, I got confirmed that Deckel had always introduced top notch executions even for "mundane" parts.

Looks like you have a special raised clamping lever on your Aloris QTCP, what is that for? The tool post has all four sides usable, these soldo today only have two,,, And what are the small hex heads on it?

The protruding tube shaft on the (5C?) collect chuck is maybe an extension that can be fitted to any chuck? I can surely imagine it's usefulness e.g. when turning tapers.

All I did today was to rough turn a sort of tube to easily pull out the spindle on the vertical head, which is not fully worked out yet.
In the process I managed to finish off the motor or the board on the small lathe, exactly at the time of finishing the last operation. The good news is that since it was horribly pathetical anyway, I had already got a 1100 kW replacement to replace it.
 
Last edited:
That is a Hardinge 5-c collet index fixture. Nice for quick work.
Has 24 index points. No masking , but the back ring is marked so it’s easy to count spaces.
See these often on E-bay.
Cheers Ross
Going to give the wife my Christmas list early this year. A hardinge 5c index fixture will be at the top of the list. Thanks!!
 
The quick change tool post shown in my post is an Aloris "BXA-I
Bit different from your more common BXA post.
Its 4 sided, in that it carries 4 tool holders with their tools.
The handle allows the body to lift off its base (curvet coupling) so that one can rotate the body to present the next tool.
Its a sort of manual turret.
The center bolt and nut secures the entire package to the machine. It is fitted with a base that has a "T" projection that located into the machine "T" slot..

The small hex nuts are the clamps that engage the wedge clamps that secure each tool holder...
I was using this post because its holders were smaller than the ones on my machines usual post, MultiFix 40 position size E post.
The smaller holders were better suited for the small boring bar that i used to make the internal threads.


The 5-c collet setup shown is the OE set for this lathe.....
full


full


Its an extension that fits to the spindle bore taper. Body is larger than the bore to allow the holding of a 5-c collet.
This setup is used to allow a smaller lathe to still grip the full sized collet.
The Lathe is a small 13x30machine with a D1-4 spindle.
Harrison flat bed CNC lathe with a Fanuc 21-i control. Can be run in one of 3 modes. Full G-code, "Guide"(which is a Fanuc quick programming language) and Harrison "Alpha" which is Harrison's graphic programming setup. Nice little machine.

Cheers Ross
 
Ross,

Thanks for showing the process of making the draw bar.
You are really going above and beyond to make the buyer happy.
I bet the lucky guy can't wait to receive it! :)
 
Thanos:
The late manual machines are fitted with a different draw bar.
There is a threaded collar that threads on to the draw bar and sets the end play That collar’s upper face has two hardened dowels sticking out
There is a second part that engages the hex on the end is the draw bar and is face drilled to fit the dowels.
You adjust the end play in the draw bar And set the adjustment by locking the upper collar to the dowels in the lower piece.
The top side of the upper collar has a 10 mm internal hex to fit the std right angle hex key.
The upper collar is retained by a snap ring.
One additional feature is that there is a spring loaded plunger inside the 10mm hex. This is a safety that prevents the hex key remaining in the draw bar.

The factory setup i removed had the late setup, so I copied the top end of the draw bar and used the factory parts.

This setup tales the place of the collar and taper pin to adjust the draw bar end float.
Also provides the safety feature described above.
Cheers Ross
Hey there Ross,

thanks for this, I new they used an internal 10 mm hex there (like on the horizontal drawbar and the quill handle) but had never given it any thought.
full


BR,
Thanos
 
The 5-c collet setup shown is the OE set for this lathe.....
Its an extension that fits to the spindle bore taper. Body is larger than the bore to allow the holding of a 5-c collet.
That's interesting, thanks for explaining. I suppose that's all proprietary, not a Morse taper? How the extension is held to the spindle and how the collet is, perhaps it has a quick release lever on the back of the headstock.?

I didn't fitted yet a collet chuck to my curent lathe but I will have to, and to the next one also. And if possible at all, even a D1 adapter,
 
Just for the record the adapter taper is #5 Morse.
Part was made by Royal along with the lever collet closer...
Unfortunately Royal no longer makes manual collet closers....

full


full


full


Cheers Ross
 
Thanks again for the explanation Ross.
This thread is all about drawbars, isn't?
I think that is a simple and clever system that removes the need for a chunky chuck and backplate which may add error and complexity. I had always wondered why lathes spindle tapers are never used for work holding beside turning between centers, now I know someone knew better.
Clearly the demand for semi-automatic machines has disappeared, so isn't made anymore, would be wonderful to see someone re-making. Go figure, there is people around making (never produced) ancient patent contraptions of no purpose.
 
Hey there Ross,

thanks for this, I new they used an internal 10 mm hex there (like on the horizontal drawbar and the quill handle) but had never given it any thought.
full


BR,
Thanos
Here is a photo of the drawbar setup from my Precision Boring Head....very similar to above, and also a photo a my little drawbar project which entailed creating a longer drawbar suitable for DIN 69871. Cudos to Ross for his efforts on his drawbar.
20230428_183552.jpg20230428_183527.jpg
 
Nice work Ross -- thanks for documenting it.

I seem to recall you had some ANSI carbide cutters for sawtooth threads that differed from the metric ones by one or two degrees in their angles. Is that right? Could you have used those cutters here?

I have a question, do you ever blue or blacken steel parts like this drawbar? These oxides don't change the dimensions significantly and do add some corrosion protection or at least make the corrosion less evident.

I've been making some parts for my circular grinder and it would be nice to be able to blue them properly. I'm not very happy with the cold blues I have tried, and have been reading about using salt solutions at temperatures > 130C to blue or blacken parts. Any experience with those?
 
Last edited:
Only have expirence with the cold blue/black or commercial black oxide.
Not sure I want to be messing with hot salts in the shop , might provoke rust on sensitive machine surfaces.
Interested in what you come up with.

Funny story about machine rusting.
Here in Northern California I have almost zero trouble with bare metal surfaces collecting rust.
Some years back I was rebuilding parts of a steam locomotive.
Job included doing a re-Babbitt job on the main cylinder cross head Required casting about 65# of high tin Babbitt.
First step was to tin the shoes where the babbitt was to be cast.
Entailed scrubbing the heated part with acid.
Did the job after work, and when I came back in the morning every bare metal surface within a 100’ radius was orange.

Cheers Ross
 
Entailed scrubbing the heated part with acid.
Did the job after work, and when I came back in the morning every bare metal surface within a 100’ radius was orange.
Hydrochloric acid. Releases chlorine gas. This catalyzes a reaction, meaning that the chlorine converts an iron atom to iron oxide (rust!) then frees itself and moves on to the NEXT iron atom, and so on, ad infinitum. To be precise:

Pure chlorine won't corrode steel or iron. For example pure chlorine gas or liquid is often stored in steel pressure tanks, no problem.

BUT as soon as you have some water (H20) around, here's what happens. The chlorine gas (Cl2) combines with the water to make hydrochloric acid (HCl) and hypochlorus acid (HClO)

H2O + Cl2 --> HCl + HClO

The hypochlorus acid now gives up its oxygen to the iron to make ferrous oxide (FeO) which you will recognise as the starting point of red rust (Fe2O3+water molecules). This liberates energy and leaves behind MORE hydrochloric acid:

HClO + Fe --> FeO + HCl

Some of the ferrous oxide will also combine with the hydrochloric acid to make more water, so the process generates more of what it needs to continue and becomes self-perpetuating:

FeO + 2HCl ----> FeCl2 + H2O

In short, chlorine gas plus water vapor present in normal air will dissolve the iron right out of your tools and convert it to rust. That's how the acid produced a huge circle of rust.
 








 
Back
Top