Shoptask 1720

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Torch
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Location: Muskoka

Re: Shoptask 1720

Post by Torch »

Nevermind.
Keyair
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Joined: Wed Aug 03, 2016 6:09 pm

Re: Shoptask 1720

Post by Keyair »

I was wrong, so credit to Torch!

Went to my local Industrial Metal Supply and grabbed a bunch of REM's and a piece of brass to make the Gib.
They didn't have anything in 5/16, so I grabbed a 12" x 1" x 3/8th and I will just have to take a shot at milling it down!
spro
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Re: Shoptask 1720

Post by spro »

I would like to edit my previous reply but that option doesn't appear. The motor plates help date the machine but that's it. Good job on that handle. That angle vise will be handy as the last step of the parallelogram.
Keyair
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Joined: Wed Aug 03, 2016 6:09 pm

Re: Shoptask 1720

Post by Keyair »

Thanks for all the help Spro!

I am blown away by what the Swedish guy did... I am not an engineer, but I do love making/fixing stuff...
The way I work is I figure out what I need, and what tools I need to get me there and find what I need within my budget and make them good.

A quick measure of the Milling head column says that the clamping footpring is 4.5" x 4.5"... is that so bad as to make it too flexible?
spro
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Re: Shoptask 1720

Post by spro »

Everything is too flexible if the speed is too low or feed too high. I've read for years that these machines are too flexible in many ways but they were not always Shoptask quality. I don't even own one but Privatech has gone all out on his. I too was blown away by his knowledge and faith in his own work, to forge onward and make it a CNC machine. There are lots of tips and inspiration at his site. This is particularly timely for you now and others who saw it previously.
Getting back to flex; since yours wasn't disassembled, the p.o. may have already measured, scraped, aligned the head column joint/flange really good. Can't know from here but that is usually where most flex occurs. It should be good enough to make that gib using that vise.
TMI but I bought a 2hp mill/drill. It shipped from California in a crate. I had to disassemble it in order to wind around sections into a basement and reassemble. The column flange to base had shims and also a reddish stuff which crumbled away. I had a heck of a time shimming that column/ head to base. Only later did it come to me. When they made the flanges, they didn't know which base it was to fit so there would be gaps even with shims. So they used something like auto body filler/Portland cement as a media on each side of the shim. Dialed it in, let it cure, dial again,tightened again then out the door. If this is done right, with an inflexible filler, the joint is about as right as it gets.
Keyair
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Joined: Wed Aug 03, 2016 6:09 pm

Re: Shoptask 1720

Post by Keyair »

I hear you Spro.
BTW, not TMI at all to share that info, carry on!

So, here is the plan...
Today, I hope to move the machine to the top of the large filing cabinet I have... I have some faced MDF that I will put under it that will have to do for now.
Once it is in place, I will do some quick checks, to see if everything is "Ok enough" to take a shot at milling the Gib replacement.

From there, I think it makes sense to invest some time and $ in checking the machine for accuracy, and stability...
I think it important to state what I have in my shop, so you guys know my level of capability, and if it will work or be accurate enough for now.
Various Micrometers up to 6", some are Chinese, but I also have M & W, Starret and Fowler. Micrometer Depth gauge(M & W I think) Set of inside spring loaded bore gauges, and a Dial Bore Gauge up to 6"(0.0005" Res), Dial indicator mag stand and 2 Dial Indicators, a rotary and a digital heads with 0.001" accuracy. Set of HF parallels.

I have couple of starter questions...
1/ Privatech used a 16mm ground rod and 2x ER15/16 collets to test the spindle alignment... The collets are easier to find, but the rod? Is "Drill Rod" good enough?
2/ I have a lot of questions about how to check and the "Inspection Process" but can someone direct me to a site or article on how to setup and check spindle runout and such stuff? I understand the basics, but as it starts with using the carriage to check along the bar, how do I know the carriage runs true and straight!
3/ The chuck that came with the machine has "Outside Jaws" fitted, and there was a another set of jaws in the box of tooling, that I assumed were the opposite.... Wrong... they dont fit the chuck. Looks like buying a new chuck will be on the cards... is this style of chuck mounting common?
If I need to replace it, maybe this 5" conversion makes sense?
http://littlemachineshop.com/products/p ... &category=
toddalin
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Re: Shoptask 1720

Post by toddalin »

ShopTask went away from the "free standing" head in favor of four columns on one side and a rigid pole on the other (the "bridge mills") connected by the workings, and even with all that, I get some flex.

Mine came with both inside and outside jaw fittings. BION, it makes a difference as to which one you put in which location when you go to tighten your piece, so if you've not yet removed them, mark them as to location. (Found out the hard way. Again, Chinese...)

I hear you when it comes to making things work using whatever is available at an economical cost. Just don't expect the machine to to be a "precision instrument" when finished.
spro
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Re: Shoptask 1720

Post by spro »

So true yet there is a starting point to bring it closer. There is info all through this site about "traming" or "dialing in" elements to make the machine parallel. So much and it starts with the bed. Bed alignment, spindle to bed usually begins with a functioning tailstock. So even in less than perfect trim, the thick gib can be made to allow further checks. The gib locks the opposite dovetail so linearity can be checked. Clean, lube what moves, reduce chatter where it can be and make that parallelogram. The stock is thicker and can be measured to see how accurate the milled surface becomes and how it is when tightened up. In that same plane, the recesses could be spotted for distance apart but that is too dicey now. By side or end milling that brass may be a test in the angle vise. It will show you what shakes, rattles and hopefully doesn't roll. Slow feeds and minimum backlash in the cross feed and lock of the everything else are required. .02$
Don't know about your chuck/spindle. Flange over taper, 80mm? Tons smarter guys than me around here about the above and later.
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Harold_V
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Re: Shoptask 1720

Post by Harold_V »

Keyair wrote: but the rod? Is "Drill Rod" good enough?
Depends. Drill rod has the capability to not be straight, or round. The longer a piece is that gets run through a centerless (which is how precision pieces are sized), the better the chance it won't be round. Armed with that thought, a guy might be wise to procure a drill (or reamer) blank, both of which are hardened and ground. They offer the best possible chance of being round and straight, and are hardened, unlike drill rod, as a bonus.
It's important for you to understand that the gripped rod must be true. Otherwise the errors included in the rod setup will confuse the information you seek to determine. The rod must run dead true in the spindle, at both ends. Only then can you rely on any readings you determine from running an indicator on the rod.
When conducting your inspections, it's a good idea to place the indicator at either 12:00 or 6:00 when attempting to determine vertical error. Likewise, place the indicator at either 3:00 or 9:00 when attempting to determine horizontal error. Any deviation from those positions offers the chance of confusion due to error in both positions.
how do I know the carriage runs true and straight!
You don't. The process you described is performed to assure that the spindle centerline parallels the ways. So long as it does, the machine (in theory) will produce a straight cut.
With this in mind, understand that there are a lot of variables that will still yield a less than straight cut. How far a piece projects from the chuck is instrumental in how straight (and round) the cut will be. If a chuck is used and the jaws are sprung, it's common for the piece to oscillate between the jaws, yielding not only a tapered cut, but a three sided cut as well. It may even measure as if it's round, but a dial indicator placed on the cut will display that it has nodes.

As has already been mentioned, don't expect this machine to be very precise. That's a big call for a lot of lathes---as they are not really precision machines, keeping in mind that's a relative term.

A bit of advice. If you see yourself moving towards better machines, don't get too deeply invested in this one. Use it as a learning curve, learning the things that will permit you to do more complex projects. You'll quickly come to understand when you've outgrown the capability of this one. If you invest too much, you'll likely never recover the investment, but you can almost always get your money back if you use good judgment. The money you'd lose would have gone towards, for lack of better description, bigger and better.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.
Keyair
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Joined: Wed Aug 03, 2016 6:09 pm

Re: Shoptask 1720

Post by Keyair »

Thanks for the input Guys.
I didn't get to putting the machine in position today, as my truck refused to start, and I spent the day fiddling with that.
Turned out to be the carb, so swapped on a spare.
Got it started, so tomorrow, I hope.

I understand the comments about accuracy(I was a QC Inspector for 5 years on Press Tooling models).
My needs are not super accurate, I just need something to make some parts for myself and projects.

I have TIG and MIG welders, sheet metal shear, slip roll and light and HD sheet metal brakes, media blasting, and powder coating equipment.
My Mig and TIG work is improving... slowly!

I just need to turn or mill some widget sometimes! :P
spro
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Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Shoptask 1720

Post by spro »

When you made that 3 hour trip, it turned out right with all the tooling as bennies. You can handle the inspections and stuff, so we don't need to tell you everything you know but it helps the next person. I learned by reading and pictures but a certain element is unlike what is normal with larger machines. The miter gear drive through the column to the head is a serious element. It should be up to the job. Can't say. The distant mentor in Sweden had his all apart and if these sets are available, price these sets. Excessive Gear lash may be evident and one part may do it in (like bad news) Cain't say from here but maybe this was done before, repaired before. The new end mills' set and vise indicate that milling was on the menu but wasn't used for a reason. You may have to face that reason, yet have friends to help through it. You will still have the gib in the machine for lathe use.
Keyair
Posts: 90
Joined: Wed Aug 03, 2016 6:09 pm

Re: Shoptask 1720

Post by Keyair »

Busy day....
Had to move 3 vehicles to get to this point!

Rolled the machine on its cart, into prep position..
Image

Then got her strapped and lifted up...
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Done!
To actually get her onto the cabinet was fun...
Because the legs of the engine hoist hit the cabinet before the unit was on the surface, I had to set it on a slow droop and push as it dropped to slide it on... Fun fun fun!
Image

The filing cabinet is an older unit, so pretty stiff, but I think I will either change it out or beef it up in the future.
The height from floor is pretty high, but I am 6' 4" so its feeling comfortable for now.
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