Arnold's take on Elmer's Grasshopper

[arnoldb]

I'm going back to the work on Monday, and having had little Tiny do a good stint on holding down papers and being a general conversation piece there, it's time for something new. Fred should do as a good stand-in for a while, but what then ?

Well, having built a couple of rocking engines and wobblers, it's time for something different and to try out my new mill; There is nothing like project work to get to know one's machines.

I had a difficult time choosing between Elmer's Grashopper (#37) and Beam (#24), but with the Grasshopper the slightly larger one (and based on a good friend's suggestion - thanks Mate ), it is next up.

First, I spent a good couple of hours calculating and jotting down metric dimensions & threads on the plans, and also checking what material I had available and compensating/improvising as needed, then it was off to the shop.

Building started with the base; I sawed a suitable section off of some 12mm Aluminium plate I bought while in SA, and milled the edges to size. I thought I had taken a photo of the stock when I started, but didn't :-[.

Almost immediately, I was made aware of a painful issue with my mill; there is not enough space between the Z locking lever and the shield safety switch mounting, and my fingers took a couple of painful knocks getting wedged in there while I was concentrating on setting depths and so on, and not looking while operating the lever.:

So I spent a couple of minutes removing the mounting, and bypassing the safety switch in the mill's wiring cabinet. I'm fully aware of the safety implications just in case anybody is wondering. Sometimes H&S gets so obnoxious that it is a safety risk on it's own. I'll use the holes left on the mill to mount a light in a sane fashion; that will compensate a bit

Having milled the base down to size, I did the layout. Permanent marker run across approximate locations and then lightly layed out the dimensions, and punched for the holes. The numbers are the metric drill sizes I need for the surrounding holes:

Milled the mounting slot for the leg. Decided to test out the machine's dials, so found the edge, zeroed the dial and cranked in 3mm from the end. Hmmm, not enough you idiot; you need to add the cutter's size as well... Fortunately a 9mm cutter, so three more full turns and spot on. I'll need an edge finder soon; for now, I used some paper with a known thickness like Tel mentioned in one of his posts - works a treat. Fortunately, I remembered to deduct the cutter's width for the other side of the slot; hit things spot on and literally split the mark-out lines:

The mill's chuck cannot take drills smaller than 3mm, so off to the drill press for the next steps; I took a chance on drilling the the 2mm holes for the leg pivot pin like this; fortunately the drill didn't wander and the bottom hole was spot on. There was only about 6mm of the drill gripped in the chuck to get the needed depth, and end of the spiral is well below the top hole:

Then some tapping followed - all 2.5mm holes were tapped out to M3, and the 3mm holes were countersunk at the bottom of the base. So that completes the base machining-wise:

Hopefully I can get some more parts done tomorrow; this build may take a while to finish.

Regards, Arnold

 

[ariz]

Arnold, some thoughts of any importance

you're already at work on a new engine: what a constancy, I would be as you are in this, but after every build I need some time to restore energy ;D

the safety shield is the first part that goes away in every new mill, I think: it's impossible to use the mill with that shield attached

finally, compliments for the choice on the next engine
but I doubt that it take you too much time to complete it :big:

 

[4156df]

Arnold,
Glad to see you're back at it. I'm looking forward to following along.
Dennis

 

[SBWHART]

A grasshopper is on my list as well Arnold not to sure when I'll get around to it though, so I'll be watching with interest.
It will give your new mill a good test.
A good start

Have fun

Stew

 

[Deanofid]

Hey, it's exciting to get to see you using your new mill, Arnold.
I always like your build threads. Have fun. We'll be in the cheering section.

Dean

 

[arnoldb]

Ariz, thank you - I've had a good break though; nearly a month without much machining !. It might take me a while to complete though; My shop time will be fairly limited in the upcoming months; mostly to weekends.

Thanks Dennis ;D I hope the build process will be worthwhile

Stew, thanks ;D. "A good start" - Double thank you; starting is the hardest choice to make!

Thank you very much Dean ;D ; I hope this thread will be up to expectations... :-[

Today's bit of work - the column.

I needed a piece of 8mm aluminium plate - marked out on some parent stock and ready for the bandsaw:

After a couple of minutes with the saw in vertical mode, done. At one point I deviated quite a bit from the line...:

Then off to the mill to get cleaned up and brought to width with a 9mm cutter:

The plate is clamped with more overhang to the right, as I set up the vise close to the left end of the table for now. A bit of a mistake, as the calibrated dial for the table is on the right hand edge, and operations would be easier closer to that side. I'll move the vise soon; it took me quite a while to get aligned... Experience should make that easier and quicker to do though.

Squaring up the one end of the plate - and a good example of a bad example... :-[ I don't have a suitable spanner for the flats on the chuck, so that wrench was used on the flats to tighten up the collet chuck... The collet closer nut fortunately does have a suitable C-spanner. I'll buy or make a spanner ASAP, or make a spindle lock for the mill; which should eliminate the need for the spanner:

Then the plate was marked out, and I drilled all the holes needed, and switched to a 6mm slot mill to do all the slotting and cut-outs. The eight 6mm holes for the cut-out sections were offset by 0.1mm on both X and Y axis into the "scrap" parts of the cut-outs, so that I could finish the cut-outs off to final size with the end mill only. I've had some bad looking parts in the past because of left-over "hole" indentations in the corners; the offsets worked a treat The first cut in the first slot was the trickiest; then I just set the mill's Y dial to 0 after feeding in to the needed depth, and took the reading off the dial after feeding out to depth; then things were easy; Feed half a turn on Z (1.125mm), feed in on Y to 0, Feed another half turn on Z, feed out to the reading. Repeat a couple of times, and the slots were done Part way into removing the cut-outs:

Having finished the cut-outs, the column was done. Well, NO... I forgot to mark out and make the decorative top :-[. Worst of all, the center point for the curve from Elmer's plans was now missing; it is in one of the cut-out blocks in the recycle bin... Fortunately, this is cosmetic only, and no real accuracy is needed, as long as it looks pleasing to the eye. So I scribed some lines on both sides of the column parallel to the top, and used a piece of round stock close to the same width of the column to mark the rounding; finger-feeling for placement in the center of the column, and even with the top. Just scribed a good line on both sides using this method:

Then it was back the mill to mill away some of the excess - purely by eye and x-y control, and then I just clamped the column in the big vice and filed to the lines.

Finished column:

Mounted on the base:

And a shot from the back; slightly out of focus though. Reason for this photo, is to show that I counterbored the screw mounting holes on the column. Elmer's original plans does not have this, but I felt having the screw heads on the column sitting in flush rather than standing out would be more pleasing to the eye... :

Regards, Arnold

 

[arnoldb]

I had a quiet week in the shop. On Tuesday evening, I had a chance to do something, but spent the time on quick short-term fix-ups on the cheapy milling vise. Some shims on the bottom of the moveable jaw guides to prevent it lifting up 2mm when tightened, and some filing & grease on the screw to make it smoother. More work still needs to be done to the vise... - one for the Tuit list.

Friday evening, I took the off-cut of aluminium that was left from the column, squared it up, and laid out the column fork on it. The plans call for 6mm (1/4") plate for the column fork, and this was 8mm thick - so a slight change to the plans:

Next it was off to the drill press to drill the tap-holes (2.5mm for 3mm threading) and for the fork pins (2mm):

Off to the mill; Cleaned out the inside of the block as per plans:

I milled out the inside part above first while it was easy to clamp the piece. Then I milled two steps on the column-side of the block to get it down to 6mm for the slot in the column; this was needed because I used the 8mm instead of 6mm plate. Next up it was the cut-outs on the sides. For these I clamped the block on it's sides rather than flat as above (little left to clamp on!), and just milled the flat parts away 3mm deep and 3mm short from what it should be. Then I used a 6mm ball nose mill (Thanks Rob!) to put in the curve. This actually worked better than I expected.

oh: Just had a thought... I could just have rotated the block 90 degrees while flat and milled the sides :-[ - Oh well, its done

With the column fork nearly done, I needed a way to slit it according to the plans... I can only do slitting in the lathe currently, and did not look forward to setting it up for that, so I chalked up a Tuit and stopped for Friday evening:

This morning (Saturday), with a late start in the shop, I worked on a round tuit rather than work on the engine itself.

First up was some thinking and a bit of C-o-C (Copyright Bogs )....

Then some precision turning and boring (well, as precise as I can be) in a bit of HRS lying around (No Zee, not Bambi!) with much thought dedicated to under-cuts and flat faces:

Some more parts were turned, bored and threaded from silver steel and CRS, a spanner flat was milled, and I ended up with this motley crew, lying on the C-O-C:

Well, I am not always good at following plans - even if it is my own, and here-and-there I deviated; even changed some measurements on the fly, but the end result is basically what I wanted:

A slitting saw arbour that I can use in both the lathe and the mill. All of the slitting saws (both of them!) I have are the same size, and with the arbour and the mounting bushes, I can use either (or both ganged) at the same time, as well as get more of the same size but different widths up to 4mm. I took great pains to make the shaft as accurately as possible; the turned down section is exactly 12mm and concentricity is at less than 0.005mm using my best DI, so that I can also use it in future for things like gear cutters/hobs or whatever needs mounting. It took me 5 hours to make that lot, mostly because I spent a lot of time trying to work as accurately as I can, and for now, things look good. I hope it is a worthwhile investment in the future as well...

Well, back to the engine. I put the above lot to immediate use in the mill. Another tuit... I need a vise depth stop - for now I just used one of my much abused toolmaker's clamps to do the job:

Slitting went like a dream; instead of the "grrching grrching grrching" I've had from slitting saws up to now, it just went "grrrrrrrrrrrrrr....."

The column fork after some clean-up:

And the build thus far:

Regards, Arnold

 

[RobWilson]

Hi Arnold


:bow: :bow: :bow: :bow: :bow: :bow: Looking great Thm: There will be no stopping you now with your new mill

Regards Rob

 

[Maryak]

Arnold,

Nice going with the new mill. :bow:

Sometimes a quick and dirty fix for jaw lifting on the vise is to put a piece of round bar between the work and the moving jaw. This gives a rolling action to the jaw lift and the workpiece tends to stay where you want/put it.

Best Regards
Bob

 

[zeeprogrammer]

You sir are a motivator of tool making.
I almost wish I didn't have a slitting saw arbor already.
However, just yesterday and even today I was thinking again about those threading die holders you made...still on my list!

 

[Metal Butcher]

Grass hopper? I missed the start of your build Arnold. Your project is coming along real nice, real nice! :bow:

I see that there won't be much left for me when I get back in the fall. Too many tough acts to follow this year!
Ya all give me a break now, ya hear! :big:

Nice project Arnold, I'll be watching with keen interest.

-MB

 

[arnoldb]

Rob, Thanks Mate ;D

Thank you Bob - I'll definitely try your suggestion on the round bar - thank you!

Carl, thank you ;D. I've never regretted making those die holders; they see constant use, though they still need finishing; my knurling wheels eventually arrived.

Thanks MB

Ya all give me a break now, ya hear! :big:

:big: C'mon toss us some bones as well; you've been so prolific there was barely anything left to choose from :big:

Not much progress to report for today... Started on the leg, but it still needs the cut-outs done and surface finishing. That deep 2mm hole through the bottom was the most difficult part; both in terms of chip clearance when the hole got deep, and the "how far did it wander" question that was going through my mind. Came out OK though; less than 0.05mm out of position on the other side. Leg so far:

And on the base:

Regards, Arnold

 

[Metal Butcher]

Arnold. You have a good sense of humor! :bow:

Hey, What do ya mean? When I got here all that was left for me to pick from was Elmer's plans! Nobody, I mean nobody, wanted them! I guess the poor quality photo copied pictures made the projects look unappealing. But,once I built a few, their beauty became apparent.

Now that "Building Elmer's Engines" has become "fashionable" I'm being crowded out by Highly skilled and talented members. You guys are all popping out of the wood work to grab the remaining projects. Sadly, I paved the way, only to be trampled by the charging crowd! Pity me! :big:

I didn't build them all though. The Butcher always leaves a little meat on the bone! ;D

Nice mill work Arnold!

-MB

 

[Deanofid]

It's coming along great, Arnold. You sure are making good use of the new milling machine. I get the impression that you're likin' it!

The slitting saw arbor came off very nice, too. Good job.

Dean

 

[Brian Rupnow]

Arnold---You are doing some mighty fine work there. Looks like it will become a very interesting engine. And thanks for stopping by my thread to see my Webster build coming together.--For me, it seems kind of nice to be working totally from someone elses plans for a change.

 

[tel]

Nice start Arnold - keep 'er comin' mate!

 

[arnoldb]

:big: - Thanks MB. What charging crowd ??? - You've set the example; now expect to be imitated ;D I actually want to build more of Elmer's engines; not having the mill up to now meant it would have been a lot more work time consuming to build many of his projects; I love my little Tiny and Fancy; even though I've had to bastardize them a bit to be metric. Same goes for the grasshopper... - so I'm working at a disadvantage :big:

Dean, thank you ;D. I'm not just likin' it - I'm LOVING it! - I'm just glad my hair is thinning; makes it easier to get the chips out ;D

Brian, thank you - you've published some great plans; there are definitely some Tuits for me

Thank you Tel ;D - I will!

Well, my Monday at work was not too blue, so a couple of hours in the shop went down well...
Marked out the leg for the cut-outs:

Then puzzled over how to clamp it in the mill to do the work - Maybe I should have made the cut-outs first and then the outside.
I settled on some brown stuff clamped in the vise as there was no real precision needed, and then toolmakers' clamps to clamp the leg with the sides against the vise jaw to get the inside cuts parallel to the outside:

Then set to work with a 6mm slot mill:

And done with the cut-outs:

Some filing to get rid of rough edges and a scrub-down with scotch-brite later - pretty much done; once again I deviated from the plans in the cosmetic department; I made the cut-outs in the leg more consistent with those in the column:

And an assembly photo:

Regards, Arnold

 

[CrewCab]

As ever, great work Arnold, always a pleasure to follow your builds ........... 8)

Take care

CC

 

[zeeprogrammer]

Scale! Something for scale! ;D
Just don't make the same mistake I did...you end up dressing them up (or down).

Nice looking stuff Arnold. Having the mill is great isn't it!

 

[arnoldb]

Thank you CC ;D - I really appreciate your input

Carl, thanks ;D - Hmmm... I was working on a leg... It was given a dressing down... Now it's bare... - hang on; wrong leg and dressing down was with tools and abrasives. Now why does bare metal seem wrong right now ??? ;D.

Scale! Something for scale! ;D

Your wish is my command - I'll try to remember! Only problem is, I can't find those W+W's for sale here in Windhoek!

Some more done; the beam - marked out:

Off to the drill press once again to drill the holes:

A side-note for anyone thinking of getting, or who have one of these cheap cross-vises: While I find it a real plus to use on the drill press, it is pretty inaccurate; from the two end-holes in the beam fed along the Y axis by ~115mm, it is out by nearly 0.75mm on the X axis - indicating that the fixed jaw is pretty far off from parallel with the Y axis, so you need to check each hole position carefully.

To the mill to get rid of excess material; I just put the beam in the vise by eye and checked shallow cuts against the scribed lines. Some fine adjusting was done by tapping the piece up or down on bits extending to get to the line; not very scientific, and most likely not good engineering practice, but it worked.... :

Next up was rounding over the ends. I could have spent a lot of time setting up to mill the rounds; It just seemed simpler to turn up (well, not even turn up - just drill holes in some correctly sized round bar) some filing buttons and do the job with a file. Buttons made with a bit of brazing rod as pin:

Rough filing the curve in the big vise:

When the curves were very near to size,I just removed the lot from the vise, and allowing the filing buttons to run freely on the impromptu shaft, used a smaller fine file to file down to size by keeping everything in my hands.

The result:

And the assembly; Carl asked for a scale, so I added a scale :

The build weighs in at just below one pound one ounce. I don't understand that though...; I was born in metric (my little tag says I weighed 3.75kg when I was born back in '72). Hang on; calculator... ~2.2 lb in one kg, so that lot weighs about 500g. A nice steak weighs that ;D - I can relate to that!
oh: I got it wrong!; what's the caliper doing in there ??? And that scale is older than I am - can't be accurate any more ;D

Regards, Arnold