Apprentice Project - Toolmaker Clamps

[ShopShoe]

90LX_Notch,

Can you share the "recipe" for the blackening solution with "apple cinder vinegar, hydrogen perioxide and salt"?

I have used the "Used Motor Oil" blackening with good results, but I am intrigued by this other idea.

ShopShoe

[90LX_Notch]

Will do.  I need to track it down.

-Bob

[Joco]

Will do.  I need to track it down.

-Bob

Bob - also very interested in a method not involving lots of heat or specialist chemicals.

[90LX_Notch]

From the Shop Made Tools thread, post number 365, at HSM:

"First "Keelan" did a write up of the process here, but you must join to access this area of the forum: http://owwm.org/viewtopic.php?t=6221...8c6b478ccc3211

If you don't want to join, you can see the results on some of his wrenches here: http://www.practicalmachinist.com/vb...g-home-189001/

As you can see, he is working with old wrenches, so he began by removing the rust by electrolysis. I'm working with new parts, so it is not necessary. But I do wash new or machined metal thoroughly with dish soap and hot water, using an old disposable electric toothbrush. If you are not using the disposable type, just use a family members.

The basic recipe, as he describes it is:

1/3 cup hydrogen peroxide
1 Tbsp vinegar
1 tsp salt

Mix together in a plastic or glass container (ask the boss before you use her stuff, for your own protection) and drop your parts in. Watch the bubbles!  Leave them there a half hour or more. My second try (my big nuts) I replenished the solution halfway through (dumped the old).

Boil some water, enough to cover the parts. Once the parts look nice and rusty, drop them in. In a minute or two, they turn black. "




I have used it a few times.  It is better to hang the part with a wire.   Newly machined parts don't work well.  Also, the part needs to be thoroughly cleaned; any oil will prevent the oxidation.  What you are trying to do is a controlled even rusting of the part.

-Bob

[ShopShoe]

Thank You Bob

ShopShoe

[Joco]

Some really useful info and ideas here gents.  Thanks for that.  I plan to try the black oxide recipe supplied on some test metal before committing it to the clamps.  When I create some larger ones I am definitely going to have a go at the rolled pin approach for trapping handles.  It seems rather elegant.

So, back to my current progress.  Its been a wet day here on Saturday with some other jobs getting some attention.  But I did mange to get some machine time.

Pic #1 & #2:
First off I needed to be able to put a chamfer on the ends of the knob blanks. Up until know I have only sharpened the steel on my Diamond Tool Holder.  Given that style of tooling and the supplied jig rather simple stuff.   Today I embarked on my first free hand grinding of some of my HSS stock.  So with a 10mmx10mm bar of HSS I set about making my very first, from scratch HSS cutting tool.  Now for you old hands this is probably all pretty trivial stuff, for someone who last tackled metal working pre High School some 30+ years ago, its a case of "holy poop, I hope this works".  So taking into account the numerous videos watched and some real life advise and demonstration by a kind soul I set forth.  These pictures show the results.  And I am pleased to say it worked admirably.   Main shape of tool ground on the white wheel and the used a fine oil stone to get a final cutting edge. I remembered reading that its only fractions of a millimetre that accounts for the real cutting edge and that stoning beyond that is pointless, so I did that, saved a heap of time and seemed to get a good result. See Pic #3.

Pic #3:
Blanks with chamfered edges using home ground HSS tool.

Pic #4:
Then it was on to making the knob that is closest to the clamp noses.   This knob will be trapped using a pan head screw.  It was drilled through and tapped to M6x1 thread using a bullet nose tap on the lathe.  Power tapped at 60rpm with lots of cutting fluid and it was a breeze. Using nice/quality HSS taps makes a huge difference to the crappy carbon steel Frost set from Bunnings I got early on.
Then using a parting blade sunk it in 1.5mm to get the groove for the trapping pan head screw.
Then a bare kiss from a countersink on both hole entrances to make a nice clean finish.

Pic #5:
This is the high knob at the back of the clamp.  It will end up with a hole through it for a tommy bar.   This one was blind hole drilled to 11.5mm. Bottom tapped, again under power on the lathe with lots of fluid by with the chuck holding the tap spinning free and using my hand on the chuck to provide resistance and an effective torque break.   Once the tap bottomed out on the hole it the chuck just turned in my hand, giving plenty of time to kill the lathe. Then the lathe was put in reverse and the tap backed out. Nothing under stress, all at slow speeds, no drama and a lovely straight and clean bottom tapped hole.

Pic #6:
Over view of current state of play.  Next is to machine the knobs for a grip profile. Not having a curler yet I am coming up with alternatives to this problem  See pic #7 for plan render of what I am looking to do.

Pic #7:
Render of the grip approach for these knobs.

 

[Joco]

Managed to steal some more shop time this afternoon and got the knobs pretty much done, bar a hole to be drilled.

Pic #1:
The making ... slow and a bit messy.  I started playing with the suds I had.  Now I have to clean it all up.  Really got to get the air powered mister gadget built.  Or figure out a really effective way to clean up suds.
Anyway, basic procedure was a simple form of dividing using a hex block designed for ER32 collets and just turning it around against a reference to ensure it was always in the same relative position in the vice.

Pic #2:
However the result was pretty pleasing.  A little bit of work with some emery cloth/paper and it will be so shiny it will frost your eyeballs.   

[bruedney]

Very nice James.

I have been meaning to make a set of these for ages. Now you have given me the  I will have to make some too.

See you sometime soon

Bruce (From Singapore)

[DTR]

Nice progress! I don't know why but it took me years to realise I needed a chamfering tool. Once I made it, it became my second most used lathe tool. I should have ground one years ago.

That's a nice alternative to knurling too!

[zeeprogrammer]

Nice knobs.
I'd left mine in their hexagonal shape...but I like these.

[mklotz]

If you grind your chamfering tool so that there is a 90 degree "point" on the left side similar to the one on the front of the tool, you can chamfer  both the inner edge of a hole as well as the outer edge without having to reorient the tool. 

Visualize a square carbide tool insert mounted with one of its vertices pointing forward and one to the left and you'll have an idea of what I'm talking about except I grind it in HSS.

Knurling is fine for adjustments that one uses infrequently or that require little force (e.g., micrometer barrel, divider setting nut) but can be uncomfortable on the hands for anything that requires some force.  Fluting is far more forgiving on stuff that must be handled often or have significant force applied.

Once the flutes have been cut, dull their edges (where they meet the circumference) for an even more pleasant feel.  A flat scraper shaped like a garden hoe works well for this job.

[Joco]

Thanks Marv, good idea.  I think that will be a second chamfering tool i will make.  This one allows quick chamfers on either side of a disk or left and right shoulder profiles.   Your design will have a right angle triangle shape pointing up the lathe axis towareds the head.  Which means, if i have visualised things correctly you will always approach the work from the right.  Having your description plus what i have and I should have pretty much every chamfer situation covered without having to muck  about with toolpost orientation.  NIce!
On the construction front I would presume there needs to be some form of clearance to allow the near side or the tool to cutting triangle to access and edge while the shaft of the tool misses the work. I think I would need to start with a 12-18mm bar to get enough clearance and still have sufficient meat left. Hmm, do you have pic of your tool?

Now I just need to start breeding QCTP toolholders.  At $29 to $35 dollars a pop not aure if I keep buying or start to make my own.  I guess 1215 or 1018 steel would both do the job and it will come down to what flat bar thickness i can source that will deliver on the needed size.

[mklotz]

While getting set up to produce holders in steel, you might want to practice by making a few from aluminum.  Easier to work and the end product is useful for non-stressful tasks like a dedicated DI holder for centering stock in the 4jaw or holding a bearing for tweaking stock into running true when held in the jaw tips.

Once you have a collection of tool holders don't be tempted to mount them on the splashboard behind the lathe so that you must reach across the lathe to retrieve them.  The safety implications of this arrangement should be obvious to the most casual observer.

[Joco]

Well the clamp is built.  I'll not bore everyone with the construction of the second clamp that needs to go with this.  It will no doubt be quicker, smoother and with less "oh crap" moments.

I have included a little gallery of pics of the final unit.   I have not yet embarked on a blueing or black oxide process.  I'll trial those on some test metal before doing anything on the clamp(s).

So a little commentary ...

Pic #1 & #2:
Front and back pics.  Back knob is loctited on with the permanent stuff which needs to be heated to 200c plus before it will release. So if I decide to black oxide things it won't be hard to remove for that process to be applied.  You should also notice that I have drilled the back knob for a tommy bar.  Since 4mm allen keys seem to breed like rabbits in my garage the hole is sized for such a bar (4.5mm diameter). A little detail, but important astetically is that the hole enters and exits at the circular part of two opposing flutes. I have to setup a handle for my countersinks so I can use them as a deburring tool for these holes.  At the moment they are a little "raw" on the edge, which I will fix.  You can also see the pan head screw holding down the forward nut.  I'll do a close up of that in a later pic.

Pic #3 & #4:
Just a front view with the jaws parted so you can better see the shape of the jaws at the front of the clamp.  Also a close-up to show the top jaw profile. You could do this profile top and bottom and for the "traditional" clamps where the knobs and threaded rod are on opposite sides that is what you would do.  For this style clamp keeping the bottom jaw square just facilitates being able to use the clamp in an upright position and being able to then use a t-slot table clamping system to hold the toolmakers clamp down at any point along the bottom jaw with no voids to worry about.

Pic #5:
Close up of the back knob with the tommy bar hole aligned to the end of a flute.

Pic #6:
Showing the use of the 4mm Allen Key as a tommy bar on the back knob.

Pic #7:
A little gratuitous perhaps but a closeup of the pan head screw holding the forward knob captive. This is a self-tapping 6g x 9mm 304 stainless screw with a thread diameter of about 3.4mm.  The hole drilled is 1/8" (3.175mm) to a depth of about 7.5mm, the screw is shortened on the grinder and carefully worked into the hole to avoid stripping off the head.  Yes I probably should have used an M3 or M4 pan head screw however I only had gunk metal M3 and M4 taper taps which I would rather not used on something like this.  I still have the option of going down the M4 path if I need to but this screw method seems to have worked ok.

[10KPete]

Very nice clamps!!  And I do love the knobs. I think the next thing I make that needs knobs I'll make 'em like that.

Pete