My Attempt at making a A2Z QCTP Holder

[wongster]

Hi,

This is not much of a project log as compared to those I've seen on this department.  But I've wanted to pen down with pics my newbie's attempts at making things with my little machines with my little knowledge.  Hope you folks don't mind.

I've gotten this little boring bar with 4mm shank from an online retailer in UK. A kind gentleman from Ireland bought it for me to help me to reduce shipping cost. But looking at the available tool holders, I found nothing to go with it.  So I thought of making my own tool holder for it.  So the adventure began with me sourcing for a 60 degree dovetail cutter locally.  Got a Dormer with a shank of 12mm, which is 2mm off my biggest ER16 collet. So I asked around in this forum and the kind folks here taught me various methods of holding the cutter between centers to turn it down to size.





With that done and test fitted to my ER16 collet, I started preparing the aluminium stock of 25mm thickness but rough cutting it on my little Proxxon bandsaw.  It took me a while to cut through the slighter larger than 50mm width due to the power of the bandsaw (with bi-metal blade).



Next, I fastened it on my tooling plate I bought from Sherline.  The smoother factory edge was used as a reference edge which I indicated it in so that it is parallel to the X-Axis.  Though the stock is now in line with the x axis, moving the indicator up and down shows that the stock is not parallel to the z-axis.  Thought I just trammed my mill.... I'll do that again in my next session.  But anyhow, the pic after indicating it for x before I stop my work:



I'm using the xbox controller to turn the stepper motors but am not doing up any gcode to run the cut.  I

More pics will be available when I continue my work.  This is to avoid being accused of spending too much time in the shop, neglecting my dearest wife.

Comments and suggestions are welcome to aid in my learning process.  I'm just doing whatever I think its right but hey, I'm a loan officer working for a bank with no engineering background of any kind.

Regards,
Wong

[winklmj]

Good luck on your adventure. And in case you didn't know, mill out the "slot" for the dovetail with a regular end mill and save your dovetail-cutter for just that--the dovetail sides. If you're holding the dovetail cutter with a collet--keep an eye on the cutter that it doesn't pull down into the work. Perhaps your collets hold better than mine did but I had that problem until I switched to a end mill holder (many use collets with no troubles at all). Unless you want to try your hand at precision measuring with dowel pins, you can use the tool post itself for test fits as you slowly widen the dovetail. Finally, if you've got the material--easier to make a few "blanks" while your at it.  Never know when you'll need another holder. Have fun!

[wongster]

Hi Winklmj,

That's a nice holder! Do you have pics taken showing the making of the brass nut? I'm still figuring how I am to approach this.

Yes, I got the idea of having to mill the slot before using the dovetail cutter from the threads in this forum 

I'll keep a look out on the cutter in the collet. Didn't think of that. The reduced shank is slightly less than 10mm. Not by choice but a mistake in counting the handwheel turn.

Thanks for sharing.
Regards,
Wong

[winklmj]

Yeah, ummm, I "made" the nut by running down to the local nut-n-bolt hardware store and buying it For 25 cents it just didn't seem worth the trouble to make one.

[Bernd]

It's quite a nice project. I haven't seen anybody use a Sherline to make a QCTP holders.

Very informative. Thanks for showing how to. Also we'll try to help as much as possible to get a newbie up to speed.

Bernd

[wongster]

You mean, the brass nut can be purchased?! and all the while I thought it was custom made... silly me.  There again, I've not seen such a nut in any hardware stores here.  I'll bring one out from tomorrow onwards.  Will ask around as and when I've appointments at industrial park or hardware stores.

[wongster]

Tonight is frustrating.  Thought I can spend some time at least to bring the stock to size when my wife is out for a church meeting.  The deepest DOC of my endmill is .75", so I thought of flycutting the 25mm stock down to .75" before I clean up the sides.  After mounting the flycutter, I remembered that I had problem with the uneven cut with the flycutter. So out came the flycutter. Replaced it with the DTI and started tramming my mill.  It was leaning to the left by around .1mm and .04mm backwards. Managed to get the z axis to about .03mm towards the left but can't seem to move it much forward (tilting back still) even after removing the shim I placed in the spacer block to tilt it backwards when it was leaning forward.

The measurement was done with a square mounted on the vise with the DTI moving up and down the blade of the square.

Anyone has any suggestion on how to tram this?  I was following the instruction provided by Sherline.  Hope I was doing this correctly all this while.

Regards,
Wong

[winklmj]

Ask for "knurled nuts".

[NickG]

I always like watching these QCTP projects, one day I'll pluck up the courage to make one myself!

Good luck.

Nick

[madjackghengis]

Hi Wong, while I have never worked on one of the Sherline mills, I can't see any reason for not tramming it as I do my bridgeport clone.  I have a plate of aluminum which is parallel front to back within the limits of my measuring equipment, and I lay it on the table of my mill, after wiping it off with my palm, to make sure there are no new dings or tiny bumps hiding, then I center the spindle over the plate approximately, and I use a Starrett "last word" indicator with a post in the collet with a hole parallel to the table, and a piece of 3/16ths rod through the hole, held in place with an allen screw, and with the indicator at the end, circumscribing a circle of about four inches or so.  I tram my head to within half a thousandth in all directions, generally pretty straight forward, and that is about the limit of my machine, given it has to have clearance to move the table, and trying to get past half a thousandth and have a free moving table is about impossible.  Your "table" should be flat and perpendicular to your column, and perpendicular to your "Y" axis, getting the column trammed side to side should be fairly easy with the hardware holding it to the base, and if you are within .04mm front to rear, you should be able to either shim it up to spec, or inspect it and find out why it is not square to the table, and use hand tools to fit it up square.  Do not trust squares you buy, but only those you've personally checked, and ensured are right on.  You can flip your square around in the vise and tram vertical, and see if it shows the same out of true, but in the opposite direction, in which case your square is right, and while shims are a time honored tradition, avoiding them, and getting the machine parts mated right is an even older tradition, and certainly of greater honor.  A great deal of accurate work can be done with a simple file and a scraper. I hope I've helped a bit mad jack

[wongster]

Thank you Mad Jack.  I just posted a new thread on the tramming and z-axis vibration problem.  If its not within protocol, please feel free to move it here or remove it.

I think my problem with the mill is not being able to get the z axis perpendicular to the table.  The instruction outlined in Sherline's book talk about loosening the 4 cap screws holding the z axis to tilt it left or right.  But when I started tightening down the screws, each will move the indicated in one direction or another.  I tried offsetting the column to the side I think will result in it being "adjusted" back when tightening but it seems that I'm chasing my own tail... Maybe I'll get the accessory that allows the column to turn at specific angles to allow easier adjustments.  As to the tilting of the column backwards, I'll try to use shim.  Not confident enough to file it off as I may not be able to recover from mistakes.

Once I can get this done, I'll be able to sweep the indicator you mentioned.

When I was lowering the spindle with the xbox controller, I can hear and feel the vibration.  It seems to come from the z axis lead screw.  Lifting it up has no such issue.  Any idea what would be the problem?  What other test I can do to pin point the culprit?

Regards,
Wong

[madjackghengis]

Hi Wong, I've got a question, do the cap screws holding the Z axis have flat washers on them?  If they don't, put some on, and try to get grade eight washers, as they are hardened.  Have you ever used Prussian Blue?  If not, it is easily found in a crafts store, as oil paint for art, and it is real useful for matching up parts.  Wipe a finger tip of blue on one surface in question on the Z axis, patting the blue with a finger tip to get a very thin and even coat just about the depth of your fingerprint in thickness, and put the other up against it in proper position, and then wiggle the two just a little bit, trying to stay on exactly the same plane you touched off in, then look to see where the blue transfered.  This will give you a good idea of exactly where all the power of the machine is transfered through, and allow you to remove high spots until you have good say 75% blue transfer, which will equate to probably 90% when the cap screws are tightened up.  The screws are merely to hold the column to the base, all the actual power should be transfered through friction between the column and the base, spreading the force evenly over a wide surface, rather than just in circles around the cap screws.  The washers keep the screws from moving things by acting as "wheels" and pushing the column to the side or otherwise.  The screws will slide on the hardened washers and find their own home spot without moving the column.  Sometimes a simple piece of paper put between the two mating surfaces will make a big difference, particularly with aluminum on aluminum contact, you might try a square of paper with holes punched for the cap screw holes.  Something like notebook paper, maybe three thousandths thick or so.  It will squish and fill any low spots, and allow for any high spots less than its thickness as well as adding friction to the "joint", and dampening to vibration.  Don't ever forget, the first machines were made with nothing but hand tools, and the knowledge of how to generate an accurate straight edge from nothing.  I hope this helps out a bit and gets you further down the road. mad jack

[wongster]

Hi Mad Jack,

There isn't any washer.  The 4 screws seats in the counterbore holes in the column bed.  The holes fit the capscrews' head with very little gap.  I'll check if I can get the mentioned washers of almost the size of the holes and trim them from there, if its possible, with a file.

Appreciate you help.

Regards,
Wong

[madjackghengis]

Hi Wong, most of what I've done in life has been troubleshooting the problem so it can be fixed, and much of this work done on old electronics, from the forties, in the service, or old machines from similar eras, with no source for replacement parts, so your dilema is one I am well familiar with.  A lot of people think the real holding power with machinery is in the bolts or other fasteners themselves, while the truth is, they are just there to put enough pressure on the adjacent surfaces so the friction times the area is sufficient to keep things from moving.  It is for this reason flat surfaces with as full contact as possible are essential, and things like shimming a side or corner to get something straight makes it easier for it to move later.  If you can't get washers in the countersinks, and if you have room, you can use extra thick washers, and long bolts, so the washers are over the outside of the counterbores.  The most important aspect of this is having both the base block and the column flat, square to the table, and with as full contact on the surface area as possible.  A piece of paper that can absorb half a thousandth of distortion is a far more substantial bearing surface than a shim taking up the clearance, but leaving a minute gap elsewhere.  Notebook paper is about three thousandths pretty consistently, cigarette papers are consistent one thousandth, and brown paper bags tend to be about five thousandths, but will take a lot of lateral pressure without giving, and also grip very well to metal.  Were it mine, I'd scrape the surfaces flat and square, but I've got some experience at this, and I have a surface plate and lots of special tools for rebuilding full sized machines.  If you've got a flat tool makers plate or some other accurate flat, you can read up on the art of scraping for fit, and don't be shy, it's not that hard, just takes a bit of practice, and you can get the machine exactly square and perpendicular.  Wish I could just come over and visit, to take a look, but it's a long drive I think.  Anything I can do to help, just ask. mad jack

[wongster]

Hi Mad Jack,

The Sherline distributor here commented jokingly that he "confirmed that I am only good at $$$$ matters...". Not very accurate but relative to my attempt in wiring up the Gecko G540 VFD output to the Sherline Speed Control.  After going through the text 10 over times, I final have visual in my head. And the circuit diagram is a simple one....    We became friends after a while.  Nice chap he is.

The paper solution sounds good and logical.  I'll try with a piece of A4 printing paper, which I've quite a lot, in between the column block and the column bed to see if I need a washer.  With the washer and bolt protruding, I'll not be able to move the spindle closer to the table.



I wish that you folks are just a drive away....

Regards,
Wong

[madjackghengis]

Hi Wong, in looking at your column, I can see where you are at, and given what little I know about Sherline machines, I gave a lathe to my sister a few years ago, I think your best bet it to take the block which connects the column to the base, and beg, borrow or steal a way to check it on a surface plate, and ensure it is absolutely as square as you have to tools to make it, as it is the heart of getting the column exactly right.  If you don't have access to a known accurate square, you can take one of your own and make it exact by the use of a straight edge on a piece of paper on a good flat table or board, draw a line with the straight edge clamped in place and the beam of the square against the straight edge, and then flipping the square to the other side and drawing a line from the exact same starting point with the sharpest pencil you can achieve, and with magnifying aid, determine if the two lines are indeed one, or if they splay out at the end.  This can also be done on a piece of metal with a known straight edge and doing the same thing with a needle as a scribe, for a fine line, and if it is out of square, stoning the beam appropriately until you can discern no deviation in the line.
    In flipping the square, you double any error in it, making it easier to see.  If I remember right, that block is held to the base very much the same as it holds the vertical column, so you need the inside of your square to be the part you concentrate on in order to gauge the squareness of that block, unless you have a surface plate and can use it to ensure the faces of the block are flat, and if they are, using the outside of the square to determine the block's squareness on the surface plate its self.  Ultimately, the accuracy of your work now will determine how you do with everything worked on that machine, and will make you either laugh or cry, yet it is the easiest fix there is as you have full access.  If you have access to a true and flat surface, even an adjustable miter gauge such as used to lay out angled lines on stock, can be used as a square, by setting it to the block in hand, and then putting the block on the surface, and comparing the gauge face to face with the block, once again, doubling any error.  I hope this helps get you where you need to be. mad jack

[wongster]

Hi Mad Jack,

That I can do.  I bought 3 squares of Japanese origin; Asahi.  They at least agree with themselves that they're square... both inside and outside.

I'll report my findings next week.  Busy for the next few days.  Wife will be in Macau for holiday next week.  Should have some extra time for some work. 

Regards,
Wong

[andyf]

Ah, Macao - hope Mrs Wong isn't a gambler!

I remember going there 30 years ago, on the jetfoil from Hong Kong. Lots of smiling faces on the way out, lots of sad faces coming back. The only other things I remember are a prawn, and the Protestant graveyard. The inscriptions on the tombstones give a good idea of the perils of sailing in the 1700s.

Andy

[wongster]

Haha... Andy, she isn't a gambler.  She doesn't know how to gamble.  She and her girlfriends were planning for their annual Bangkok shopping trip when a 2nd bomb exploded.  I told her to consider changing her destination.  Macau will be for its hotels while they do their shopping at Zhuhai, which is right next to Macau.

Regards,
Wong

[johnny123]

hello
What tpi are you using in that bandsaw? I picked up an old three wheeled 1940's lathe and thinking of converting it for aluminium and brass cutting. Bands measuring 65 1/2'' are not available to me in my town, so I might have to get some made with the right tpi.

[wongster]

Hi Johnny,

I got this from Proxxon site:

Bandsaw blade of bimetal for MBS 240/E
Carrier belt of alloyed tempering steel, sawing teeth of wear-resistant high-speed steel. Varying teeth 10 - 14 TPI. Ideal for cutting all standard steel qualities, non-ferrous metals and stainless steel.

NO 28 172     1,065 x 6.0 x 0.6mm

Regards,
Wong

[wongster]

After the painful process of tramming my mill, I get back to fly cutting the top of the aluminium block.  Everything went well and I'm able to be at around 0.02mm over the 150mm stock.  Now I'm ready to start work on the toolholder.

I spread a layer of blue acrylic paint over the surface so as to mark the slot to be milled.  As this is my first attempt in milling the slot and the dovetail, I play it safe by cutting off a small chunk of stock sufficient to make 2 holders.  The layout lines were scribed on using my newly acquired digital height gauge. This is a Taiwanese made that is within my budget.  It cost me SGD260.  The Mitutoyo gauge which I initiall wanted is priced at around SGD900.  I trust Mitutoyo more as my vernier caliper and micrometer always return to zero when the jaws are closed.  Not true for this Taiwanese gauge. It always go back to either 0.1mm or -0.1mm.

I use a centre finder to locate the bottom left corner and "dial" in from there using Mach3 MDI (I do not have handwheels on my mill. I've been using XBox360 controller to move the axes).  The bottom of the slot was milled first to full depth and I moved from there till I reached the opposite edge.

The dovetail was done next.  This is much easier than I thought.  Now that the dovetail is done, I'll do the cleaning up and drilling / tapping of the set screw holes and the slot for holding the tool in the next session.

Some pics below on my progress:

After cleaning up the sides.



Milling the slot starting from bottom



Slot done



Cutting the dovetail



Dovetail done



Another angle



Test fitting



Comparing with the original



Rough cutting to almost actual size



Another test fit



The gap looks big. Hope it wouldn't affect the performance of the holder.

That's all for now.  I'll do the cleaning up and mark the hole for set screws and do the slot for holding tool in my next session.

Regards,
Wong

[andyf]

  Looks pretty good, Wong. I don't think the gap will cause you any problems at all; it's the pressure on the dovetails which holds it in place. On one I made, the dovetail came out so wide after a miscalculation that I had to to stick a 1mm shim on one side to make it work; it still works today, 6 months later.

Andy

[winklmj]

Looks good! When I made mine, I took the tool post off the lathe and did my test fits while the part was still on the mill. That way I could sneak up on a good fit.

[wongster]

Thanks for the encouragement.

I measured the gap of both the original and the one I made.  Strange enough, the gaps are both the same though mine looks wider. Could it be the colour playing tricks?

How would you folks approach the milling of the slot?  I went all the way down to the final depth and from there side mill all the way to the next line at the opposite end with the z axis locked.  This is to prevent the backlash on the lead screws from "screwing" up my work.  Would you folks mill to the full width of the slot on each pass while moving z down?

Regards,
Wong

ps: I've started a blog to document my progress of this hobby.  Its at wongstersproduction.blogspot.com.  Comments and pointers are welcome.