Author Topic: Currin's Travelling Sherline Show  (Read 11174 times)

Offline Hugh Currin

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Currin's Travelling Sherline Show
« on: June 26, 2017, 06:18:02 PM »
Well now, this is gonna be exciting. We've decided to move from Klamath Falls, Oregon to Prescott, Arizona. But for shop work it gets worse. We've decided to sell our Oregon house before buying in Arizona. Probably buy property in AZ, sell our house in OR, then build in AZ. We'll be homeless for at least a year.

No wait, it gets worse for shop work. We'll be living the Snowbird life for that time. Living in our trailer wintering in AZ and summering in the Pacific Northwest (maybe Idaho). Oh man, I'm told if we like the Snowbird life we might even do this for a few years. No shop.

Now I can't imagine having no shop, something must be done. I need a hobby machine shop that I can carry in part of a pickup bed. Doesn't have to be large, just something to play with and build a few engines. Fate would have it that some time ago I purchased a Sherline shop including lathe, mill and lots of tooling. The goal was to convert the lathe to CNC which I have done. But now it looks like a good base for a traveling shop.


I'm an advocate for CNC. Maybe 'cuz I get along with computers, like to watch a CNC do its thing, or that I'm not a very good at machining. Take your pick, but I want this traveling shop to be CNC, particularly the mill.

The Sherline CNC lathe is a good start. I mentioned it in another thread here on MEM. After some consideration I decided to get a milling column for my lathe from Sherline rather than carry a lathe and a mill. This came set up for CNC,  just had to add a stepper motor and wiring.


The column base mounts to the lathe bed just as the spindle does. It's just like the standard milling column and the spindle mounts to the column slide just as it does to the lathe bed. Converting from lathe to mill, or mill to lathe, takes maybe 2 minutes. That is without truing anything, but for many things it's likely OK without. The keys should keep it reasonably straight. Not the whole story. You can't leave the vice on the mill while doing a little lathe work. So you have to re-true the vice, etc.

The lathe set up with the column in the background is shown below.


I'll use my Gecko G540 controller box and a mini-ITX computer for stepper control.


Ignore the O2 tank in the background. Note to self: I must get a smaller keyboard.

I set the system up and have it working. The first thing I found is the lathe cross slide has a travel of a little over 2.5. OK for lathe but a little skinny for milling. I found that Sherline offers an 8 table for just this reason. That increases the milling envelope from 2.5 to 4.5. I added one and it's much more reasonable. The throat of the mill is fairly small also. But not to fear, Sherline makes riser blocks to increase this 1 or 2. My tooling included the 1 block.

I'm thinking of building a box for the lathe/mill. A second box for the controller/computer. A third for tooling. And likely a fourth for materials.

I think the best way to see if this is going to work is to build something with it. So look for a build log with the Traveling Sherline Show, likely a small (small, du) LTD Stirling.

I think I need some tooling to cut off stock. Can't run a 1 bar through the spindle and part it anymore. Thinking of a portable band saw with horizontal attachment. It has larger capacity than a compact cut off saw. It also can be set up as a vertical band saw. Anyone have experience? Other ideas?

Thanks.

Hugh
« Last Edit: July 04, 2017, 10:09:11 PM by Hugh Currin »
Hugh

Online b.lindsey

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Re: Currin's Travelling Sherline Show
« Reply #1 on: June 26, 2017, 06:31:27 PM »
That will do well HUgh!  Does the mill column have its own motor drive or do you simply convert the lathe head to moun to the dovetail of the mill column?

Bill

Online Dan Rowe

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Re: Currin's Travelling Sherline Show
« Reply #2 on: June 26, 2017, 06:55:19 PM »
I have been using a portable band saw for cut off work for years. I would consider a good vise to clamp to the tailgate a better choice with the band saw, and the vise will be handy for other uses. Just my 2 cents.

Dan
ShaylocoDan

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Re: Currin's Travelling Sherline Show
« Reply #3 on: June 26, 2017, 08:09:16 PM »
Hugh, sounds like you're all in for the new adventure, so,  :cheers:. I don't know how you are going to be "snowbirding" , but, I know a couple of guys with motor homes that tow a small shop trailer with them. When Dad and I worked construction, we shared a shop trailer. If we were on a job for longer than 4-6 months, one of us would go get the trailer. To be honest, when you're "full-timing", you'll find it comes in handier than one might think.

Eric

Offline Hugh Currin

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Re: Currin's Travelling Sherline Show
« Reply #4 on: June 26, 2017, 10:13:44 PM »
Bill: Thanks. The mill set-up uses the same spindle as the lathe. I have an encoder on the spindle for lathe threading. I could try rigid tapping if the Sherline had an auto go backwards switch. Now that's scary.

Dan: One vote for the portable band saw. Thanks. What type of vice are you using with yours? Do you have that horizontal set-up or something similar?

Eric: No such luck with a motor home. We have a 19' Escape trailer currently pulled with an XTerra. The plan is to get a medium duty diesel pickup, a strong tonneau bed cover with a small side by side off-road vehicle on top. So the bed will be available for the Traveling Shop and everything else that doesn't fit into the trailer. We thought about two vehicles with a shop trailer but the logistics got too complicated.

Thanks for looking in.

Hugh
Hugh

Online Dan Rowe

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Re: Currin's Travelling Sherline Show
« Reply #5 on: June 26, 2017, 11:41:06 PM »
Hugh, my bench vise is simply a 4" vise with pipe jaws. I have a box for the saw but it is always on the shelf just below the vise. They are easy to use by hand much quicker than reaching for the hacksaw except for small stuff.

Dan
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Online Kim

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Re: Currin's Travelling Sherline Show
« Reply #6 on: June 26, 2017, 11:50:40 PM »
Wow Hugh!  This is a big change!
And certainly sounds like a great adventure :)

Are you going to store your big equipment till you're done full-timing, and can move it into your new big property with an equally big shop?

Kim


Offline Hugh Currin

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Re: Currin's Travelling Sherline Show
« Reply #7 on: June 27, 2017, 04:30:26 PM »
Dan: Are you using a horizontal table with the portable band saw or hand holding? Looks less expensive to get a dedicated portable horizontal band saw. But haven't seen one that does horizontal and vertical.

Kim: The idea is to downsize the house, which is a trick since we're now in 1100 ft2. Probably just put everything on one floor. I expect the shop to go from 20'x20' to maybe 15'x20', but don't know yet. The big equipment would fit but difficult (or expensive) to move it all that far. It is a little large for what I do so I may sell the big stuff, then get a 8"-10" lathe and Tormach mill (size to be determined) when we land. It's up in the air right now.

Thanks.

Hugh
Hugh

Online Dan Rowe

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Re: Currin's Travelling Sherline Show
« Reply #8 on: June 27, 2017, 04:47:04 PM »
Hugh,
I have the Milwaukee portable band saw but not the deep cut version and I use it by hand. When I added a power service to my shop, I had everything set out and I knew the service pole was too long. I asked the lineman what he had to cut the pole with and said I had a portable band saw. He did not have a better way so he used my saw for the job.

I have thought about one of those rigs to make it work like a chop saw but I went with a larger band saw for that work and the portable saw gets most of the jobs as it is usually quicker.

Dan
ShaylocoDan

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Re: Currin's Travelling Sherline Show
« Reply #9 on: June 27, 2017, 05:26:25 PM »
Hugh, Knaack makes a great selection of "gang box" type tool boxes. You might be able to put a whole sherline shop in one.

http://www.knaack.com/

Cletus

Offline Hugh Currin

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Re: Currin's Travelling Sherline Show
« Reply #10 on: July 09, 2017, 01:24:14 AM »
Hugh, Knaack makes a great selection of "gang box" type tool boxes. You might be able to put a whole sherline shop in one.

Cletus
Cletus:

You're likely right, a whole Sherline Shop would fit into one of their cabinets. But then you have the problem of moving their cabinet around. Thanks for the ideas, I'll have to address the portability in due time, and time flies.

Hugh
Hugh

Offline MJM460

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Re: Currin's Travelling Sherline Show
« Reply #11 on: July 09, 2017, 04:06:08 AM »
Hi Hugh,

It's a great adventure you are starting on, I hope you will start a thread about your travels.

I am sure a band saw is great to have, but for portability, it is hard to beat a good quality frame and a bunch of new, good quality blades.  Not having a band saw, I cut off bits of 25 mm x 50 mm steel without too much trouble, but admittedly I do not go in for big repetition jobs.  A block of wood clamped on keeps me pretty square so I can finish off on the mill without too much waste.

For travelling, space is always precious, weight best left behind so its hard to beat a frame and blades, and throw in a junior saw frame for good measure.  And have a great trip.

MJM460
The more I learn, the more I find that I still have to learn!

Offline Hugh Currin

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Re: Currin's Travelling Sherline Show
« Reply #12 on: July 09, 2017, 04:25:03 AM »
MJM:

Thanks. Several above have suggested a manual hacksaw. I'm the lazy type and hate this thought. I'll have to see how much room we end up with and that will probably dictate a lot.

Thanks.

Hugh
Hugh

Offline Hugh Currin

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Re: Currin's Travelling Sherline Show
« Reply #13 on: July 09, 2017, 04:25:45 AM »
OK, I'm getting frustrated here. I decided to make some top jaws for the Sherline 3 jaw before continuing with the Stirling build. Started to set that up and realized I needed several more end mill holders for CNC. Not a problem, I'll just make half a dozen blanks or so. I have a CNC Sherline Lathe which will cut threads. Set up the code and run it half a dozen times, no problem.

Well, I've used the Sherline Lathe little, hardly touched a CNC lathe, and it's all new equipment to me. What could go wrong? I've been trying to get good CNC code and resulting part for 3-4 days. I have had trouble hand coding a CNC lathe and setting up the tools for same. The part needs 4 tools. SO, I think I now have a program that is behaving, the computer is set up reasonably, and I've got an idea of setting tool offsets for the lathe. This has taken several days of nearly trial and error. But all those are in hand, sort of.

But I'm finding the QCTP is slipping. This is devastating for a CNC lathe, it needs to know where its tools are. I looked around the Internet and found a few references to slipping QCTP. The consensus was there may be a convex surface on the "cross slide" or the QCTP itself. I checked this on the Sherline and as close as I can tell both the QCTP and Sherline table are flat.

The QCTP is from Little Machine Shop, 0xA, developed with Tormach. I had the same problem with an A2Z QCTP, thus the Little Machine Shop Version. The T-nut from Little Machine Shop is quite narrow. Some Internet sites suggested this may "dome" the T-slot allowing clamping only near the T-nut and bolt. That would allow easier twisting of the QCTP since it's supported mainly near it's center. One solution suggested was increase the length of the T-nut. That would spread the load to the outside of the QCTP thus resisting torque better. SO, I built a new T-nut system as below.


The T-nut on the left is the Sherline compatible version from Little Machine Shop. The right is my longer T-nut system. Also shown below:


The main difference is the longer T-nut to spread the load over the base of the QCTP.

Another suggestion was to place some paper between the QCTP and table. Not run of the mill paper but low clay content paper. I placed some 25% cotton paper (left over from a dissertation, thank god) which seemed OK. This may not be optimum but what I've tried so far.

The last run, with longer T-nut and paper, worked better than prior runs. However, the QCTP twisted about 0.045" at some 2" (1.3deg or so). Not much but 0.030" or 0.040" makes quite a difference in the thread.

The process is, prior to CNC, drill and cut a 3/8" hole 0.055" deep using an end mill. The CNC then bores this out using a boring bar to 0.670" diam. using many passes with 0.005" depth of cut in aluminum (5in/min and about 1200rpm). This is where the QCTP slips. Then groove the bottom of the bore for threading run out. Finally bevel the bore with the threading tool, and thread. Initial threading using 0.0025" depth of cut. The canned cycle reduces the depth of cut as thread depth increases. I think these are conservative cuts in aluminum even for a Sherline, and I'm still getting some "drift" of the QCTP in rotation.

The set up looks like this:


I did, after boring, reset the threading tool to cut the threads. This worked well and the blank fit onto the Sherline spindle well:


The end of the blank showing is a prior trial thread, too small. But the one fit to the Spindle is the right size. So, the CNC threading is working. However, the boring is shifting the QCTP enough to throw everything cockeyed.

Someone suggested applying sticky sandpaper to the bottom of the QCTP. The grit would then work to prevent slippage, similar to the paper. The QCTP body is hardened so drilling for pins isn't a good option. I've thought of building an insert what would mechanically prevent the QCTP from turning. Something like this:


Has anyone else experienced this slipping of a QCTP? Any suggestions? Like I said, this is starting to frustrate me. Such a simple thing but causing no end of problems, now and in the future.

Thank you for any help you can offer.

Hugh
Hugh

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Re: Currin's Travelling Sherline Show
« Reply #14 on: July 09, 2017, 04:39:31 AM »
I had the same thing happen on my a2z qctp on my sherline, wound up making a plate like the insert ypu show in your post. I extended the plate out so it is large enough to run bolts into both t slots to lock it in place.
I set mine up so that the plate screws to the bottom of the qctp in several places, and the center bolt just goes to the plate. The plate has slots around the edge, so I can put 4 bolts into the t slots, and allows me to set the qctp at an angle if needed. No slipping at all.