Shop gleanings

[mklotz]

I'm in the process of building Bill Harris' steam roller. Jeff02 is also building it - you can follow his progress here...

http://www.homemodelenginemachinist.com/index.php?topic=8716.msg93353;topicseen#new

Given the length of the project, my laziness and not wishing to compete with Jeff, I'm not going to do a build thread.

However, I promised Zee that if anything worth reporting happened, I would be sure to pass it along. That's the object of this thread. Some of this will be boring to our more experienced members but I sympathize with many of our members who claim the visual prodding induced by seeing how someone else does something, even the ordinary stuff, can be very helpful. I'll try to stick to things that at least have some chance of satisfying that objective.

On with it...

Today's job was to square and bring to size a 1/8" plate that is the base for the engine and boiler. I seldom mill directly on the table but the size (5-5/8 x 7-3/8) of the part demanded that so I set it up as shown below.

Years ago I made an alignment block for jobs like this. You can see its red top near the top of the picture. It has three holes spaced the same as the table T-slots so it can be bolted down in a variety of postures. Its reference surface has a small undercut so errant swarf can't interfere with alignments. Using a DTI, I aligned it with the Y-axis to serve as my master reference.

Note that clamp studs are not used to secure it. If you do this, use low profile bolts as I did lest the studs interfere with the spindle. It's a lesson I learned from experience.

The three holes are important too. Two bolts are plenty to secure the reference bar but, as you can see from the photo, the third hole allows one to mount a clamp right in the middle of the reference bar - exactly where you are most likely to need a clamp - trust me. The next photo shows the clamping arrangement in more detail...

Referring to the first photo again, the workpiece is butted against a parallel butted against the reference bar. This pushes the edge to be milled away from the reference so I can cut all the way to the edge. The edge to be cut is aligned with one of the T-slots so that the milling cutter will have clearance below the workpiece.

The other end of the workpiece is secured with two of my smaller clamps. Whenever possible, I prefer to use my smaller clamps to maximize the vertical clearance for the spindle. I've standadized on 1/4-20 for all my small clamps so I made up a collection of 1/4-20 T-nuts that fit the mill T-slots. One of the smaller clamps would probably be adequate but I'm a belt-and-braces type of guy.

Now, I just know someone is going to ask what that silvery thing hanging into the photo frame from above. It's a midget tripod head that I picked up in a camera store.

I replaced the nut that secured the bottom of the mill depth gauge with a union nut and screwed the tripod head into that. This means it maintains a fixed relation to the spindle (and tool) as the spindle is moved up and down.

It's aluminum so I fitted it with a steel plate so that I can attach various magnetic stuff to it - like this multi-LED light...

picked up for a couple of bucks at, where else, Harbor Freight.

Regardless of where the spindle is, the light is always shining on the tool in use and, when I need light elsewhere it's easy to pull it off and use it as a hand-held "flashlight".

I'll add to this thread as I do more things that I think might be quasi-inspirational but, in the meantime, feel free to add any ideas you have that might give others useful ideas.

 

[bearcar1]

Well done Marv. It is exactly those types of setups that get taken for granted most of the time and leaves the newbies hanging in the breeze wondering "How do I..." BTW, I really like that usage of the swivel mount. I have one in the drawer and have always wanted to find place to use it. Cool beans! 8)

BC1
Jim

 

[zeeprogrammer]

Nice Marv.
I like the idea of this thread.

 

[Hamstn]

Thanks Marv. It's the post like this that make this site top notch.

Could you show a close up of the undercut as you put it. I assume the corner or edge where it meets the the table has a bevel?

 

[Philjoe5]

Do I have this right? - All four sides of the plate can be milled square by placing each milled edge against the reference alignment block thus requiring indicating only one time? Wow, what a great idea.

I'm with the other guys - keep posting these tips.

Cheers,
Phil

 

[mklotz]

Hamstn,

The undercut is actually a notch made with an endmill. A bevel would work just as well, I'm sure. The idea is to make a place for the trapped swarf to go instead of having it obstruct the contact of the workpiece with the reference bar. If you look at the inside corner of a quality machinist's square you'll see that the it has a cutout so that any burrs on the corner of the part won't affect the measurement. It's the same principle.

Phil,

Yes, you've got it. A single reference plane is often more flexible than the traditional two orthogonal surfaces. I've used that silly reference block in many, many setups over the years.

Zee,

I thought it might appeal to you. I hope others will contribute to the thread. Showing setups for nebulous tasks forces the reader to think about what he could do with such a setup, how he could do it better, and how the idea could be expanded. With setup being 90% of most jobs, such stimulation is a good thing.

 

[Deanofid]

Good on you for a thread like this, Marv. A few of us were talking about this very thing a few days ago on Jim's "Geneva" project thread. How much to put in our threads? Well, put it all in, I say. The old heads can skip the boring bits, and it will give the new fellows a chance to become old heads someday.

I like this kind of stuff 'cause it often reminds me of something I know, but have forgotten, or that I want something like a spindle lamp!

Keep it up.

Dean

 

[Troutsqueezer]

Ditto to all the above replies to this thread. Thm: I love this stuff.

-Trout

 

[tel]

Good one Marv - any time I do a job like this it ewnds up a right old cobble-up, I'll take the trouble to make one of those ref. bars.

 

[ariz]

thanks for sharing Marv, this thread is very useful for us newbies or near-newbies, for everyone I think
I'll follow for sure

 

[Lew Hartswick]

With the addition of a few more holes in the ref. bar and the use of a protractor head
on a machinists square it can be used to align a flat piece to cut various angles too.
...lew...

 

[mklotz]

The frame crossbars on the steam roller need holes drilled and tapped in both ends. At 1" wide and 6.5" long, they seemed a bit "spindly" to hold in the rather shallow vise jaws. What's really needed is a largish angle plate but I don't have one of those.

My compromise was to press one of my large V-blocks into service in a somewhat unconventional setup. The V-block is square so it will hold the part truly vertical and it's tall enough to offer somewhat better support than the vise. As a bonus, it has two hefty clamps "built-in" to lock down the part.

Here's what the final setup looked like...

and a closeup of the V-block...

By clamping the V-block against my (already aligned) reference bar, the part is automatically aligned to the Y-axis so it's just a bit of work with the edge finder to locate the hole positions and drill and tap.

The lesson to take away from this is to learn to look at your tools in terms of their basic function rather than in terms of their typical use. A V-block is typically used to hold round stock horizontally but, basically, it's just a precision block of steel equipped with clamps and, as such, can be used in any number of arguably unconventional ways to fixture a workpiece. The same remark applies to all your tools; therein lies ingenuity.

 

[arnoldb]

Marv, thank you for showing these handy tips - I'm sponging them up as fast as I can.

I have a question on the last one though; if you don't mind.

From both the photos, it appears that you have the clamp positioned lower on the step-block end than on the V-block end - unless your camera is cheating my eyes. If it's a camera cheat, please ignore the question coming up...

Would it not be better to have the clamp slightly higher on the step-block end than on the V-block end, so that it clamps toward the middle surface of the V-block - instead of on the edge of it? For drilling and tapping your setup should be OK as there should be no lateral forces, but if one tried to put an end mill to it, things would surely slip out as the V-block is just clamped on edge, especially as it's only supported on one side ?

Kind regards, Arnold

 

[mklotz]

I think it's a camera artifact, Arnold, but, regardless, you're absolutely correct. The aft end of the clamp should always be a bit higher than the prow.

I didn't mention it in my original post but this lash-up would be *totally unsuitable* for milling. The workpiece is sticking out of the clamps way too far to handle the side loading of milling.

It works for this task because, when drilling, all the forces are vertical, the end of the workpiece is supported by the table and the clamp merely keeps the part vertical.

 

[kvom]

I don't have a large angle plate or v-block; my "solution" to clamping the 6" vertical piece would be to use two 1-2-3 blocks clamped in my vise with the 3" sides vertical, and a separate clamp at the top of the blocks. It's all good if it gets the job done.

 

[shred]

I don't have a large angle plate or v-block; my "solution" to clamping the 6" vertical piece would be to use two 1-2-3 blocks clamped in my vise with the 3" sides vertical, and a separate clamp at the top of the blocks. It's all good if it gets the job done.

Also remember that 1-2-3 blocks with tapped holes can be bolted together and things then bolted to the resulting bit... could make a 1-2-6 block that way.

 

[mklotz]

The steam roller calls for two arched C-section frame members that hold the driver's seat over the steerable roller. When finished, they look like this...

The plans booklet shows a partially dimensioned sketch for these parts. There was no need to fully dimension since, at the time the plans were published, a foundry was supplying castings for these parts. That foundry is history so it was necessary for me to fabricate the castings. There are many ways to do that but I chose to carve them from the solid.

Each arch has two different radii and the centers of the arcs are not the same because the arch is wider at the bottom than at the top. This meant using geometry to find the centers and radii and then scaling the latter according to scales derived from other parts shown on the print - a fine little applied math exercise. The sections at each end of the curved part are straight so that means that cutting them involves both rotating and translating the RT. These manipulations aren't particularly difficult but they do require a lot of careful dimensional bookkeeping.

The work starts with drilling two 1/8" holes at the centers of the arcs...

These holes will fit over the 1/8" pin fixed at the center of the RT. It's just visible at the top of the picture. With the RT set to zero, the plate is affixed to the RT...

and the edge aligned to be parallel to the X-axis (no photo of that procedure). This alignment is required so that the straight portions of the cut are not canted wrt the curved portions.

Starting the cut along the inside of the larger radius...

The larger radius cut completed...

After the inside cut is completed, the outer radius is machined. This frees the outer waste stock and leaves behind the vertical "wall" that forms the outer portion of the C-section...

The part has been remounted on the RT using the second 1/8" hole as the center and the inside of the second radius is being cut...

The inside cut completed...

After some rearrangement of the clamps to provide clearance, the part is freed from the parent stock by cutting along the inner edge of the part. This leaves behind the inner wall of the C-section.

The curved edges of the part are cleaned up using the drum sander jig I built for my Dremel...

Finally, the two arches installed on the steam roller frame...

 

[ozzie46]

Outstanding Marv. Thm:

Ron

 

[kustomkb]

Very nice work Marv!

I like your drum sanding set-up too.

 

[SAM in LA]

Marv,

Thanks for the education.

SAM