Re: Unimat 3 - replacing/making new gibs
I had a twisted bed on my DB200.
It was bolted to a large 2" x 12" board when I bought it. Over time the board had warped and twisted the cast aluminum base and the two round linear rails with it.
I was able to correct it by placing it on a flat metal plate and twisting the frame in the opposite direction. I put spacers roughly equal to the amount of warpage under the two opposing corners that were touching the plate and then slowly clamping the other two corners down onto the plate. Basically over bending it so it would eventually rest in its original position.
Between each attempt I set the two linear rails on 123 blocks and then indicated the four bottom corners.
Did not sand or machine any material off of the bottom in order to maintain the factory dimensions from the bottom to the V grooves the linear rods sat in.
Took my time and eventually got everything pretty straight and parallel.
Finished by bolting the machine down to a flat 1/2" thick aluminum plate. Has stayed flat since.
Jay
Hello:
On Sun, Jul 10, 2022 at 09:59 PM, Keith S. Angus wrote:
Provided the gib is thin enough ...
... not a high precision item. Just get a bit of brass the right thickness and get filing.
Easier said than done given the size of these thinguies.
I'm in the process of making a jig to hold the brass at the right angle to let the Dremel thing do the milling.
I'll post results when done.
With respect to precision:
While trying to fix other things I have come across and which I will ask about in another thread (twisted bed anyone?), I undertook the replacing of the headstock bearings (SKF 6003 ZZ), rather? daunting if you don't have a press.
I also had a look at the some strange carriage movement I had noticed and at the rectangular gibs holding it on to the ways.
I assume that the gibs are there to keep the carriage against the ways (prism and flat) while at the same time keep it running parallel to bed's axis.
I also understand that if this does not happen as it should, the carriage could *lift* (remember the GM Corvair?) and or *wiggle* instead of travelling straight along the ways as the feed moves it forward or backwards.
Now, this is a photo of the carriage gibs in my U3:
While they are? both of the same dimensions (LxWxH), the one on the left does not seem to be the right width.
Both are tightened as far (left for the one on the left, right for the one on the right) as the holes they have allow.
But only the one on the right can be tightened close enough to the metal so as to keep the *wiggle* under check.
I can notice the bottom edge of the carriage (border close to the operator) move more than the opposite border.
In one direction with forward feed and in the other with backward feed, which stands to reason as the border close to the operator is the one that has the gib with the most border separation from the underside of the way.
It is clear that this is not something adecquate and that a new set of gibs is in order.
A bit thicker and a bit longer could be a good thing but the width is clearly very important here.
I assume that the gibs have to touch the underside of the ways, but with what tolerance?
Thanks in advance.
JHM
|
Re: Unimat 3 - replacing/making new gibs
On Thu, Jul 14, 2022 at 07:14 PM, @juliushenrymarx wrote:
I assume that the gibs are there to keep the carriage against the ways (prism and flat) while at the same time keep it running parallel to bed's axis.
No, or at least you are half right. The gaps you have highlighted should not be closed up. I would expect to see a gap of about a millimetre both sides. Moving parallel is ensured by the prism shape. Nothing else should do the job, as there is the possibility of conflict between the different guidance if the machining under the bed does not agree with that above. Even without these two pieces there should be no wiggle. Their only purpose is to stop the carriage lifting off the bed, and this is unlikely since the cutting forces nearly always push the carriage down onto the bed. I'm pretty sure I've used lathes where there has been nothing holding the carriage down, except its own weight - but they were big, and the carriages had plenty of weight!
|
Re: Unimat 3 - replacing/making new gibs
Hello:
toggle quoted message
Show quoted text
On Sun, Jul 10, 2022 at 09:59 PM, Keith S. Angus wrote:
Provided the gib is thin enough ...
... not a high precision item. Just get a bit of brass the right thickness and get filing.
Easier said than done given the size of these thinguies. I'm in the process of making a jig to hold the brass at the right angle to let the Dremel thing do the milling. I'll post results when done. With respect to precision: While trying to fix other things I have come across and which I will ask about in another thread (twisted bed anyone?), I undertook the replacing of the headstock bearings (SKF 6003 ZZ), rather? daunting if you don't have a press. I also had a look at the some strange carriage movement I had noticed and at the rectangular gibs holding it on to the ways. I assume that the gibs are there to keep the carriage against the ways (prism and flat) while at the same time keep it running parallel to bed's axis. I also understand that if this does not happen as it should, the carriage could *lift* (remember the GM Corvair?) and or *wiggle* instead of travelling straight along the ways as the feed moves it forward or backwards. Now, this is a photo of the carriage gibs in my U3:  While they are? both of the same dimensions (LxWxH), the one on the left does not seem to be the right width. Both are tightened as far ( left for the one on the left, right for the one on the right) as the holes they have allow. But only the one on the right can be tightened close enough to the metal so as to keep the *wiggle* under check. I can notice the bottom edge of the carriage (border close to the operator) move more than the opposite border. In one direction with forward feed and in the other with backward feed, which stands to reason as the border close to the operator is the one that has the gib with the most border separation from the underside of the way. It is clear that this is not something adecquate and that a new set of gibs is in order. A bit thicker and a bit longer could be a good thing but the width is clearly very important here. I assume that the gibs have to touch the underside of the ways, but with what tolerance? Thanks in advance. JHM
|
Re: Unimat 3 - replacing/making new gibs
On Sun, Jul 10, 2022 at 08:53 PM, @juliushenrymarx wrote:
I still have to give this post a good read and understand what it all means.
Having looked at the post, the problem it shows, of the strip twisting, has never occurred with anything I have worked on, and I don't see how it could. Provided the gib is thin enough to allow the dovetail to slide freely, and thick enough not to just bend as the screws are done up, and provided there is a little clearance top & bottom, there shouldn't be a problem. Bevelling the edges helps with small strips as it increases the contact area. If you have to file the strip to size, why not bevel the edges while you are at it. The strip just finds its own position and that's it. If you want to locate it with the screws the U3 manual shows a shallow groove filed in line with the screw point, so the strip travel with the top slide rather than staying with the base. You probably wouldn't need that, but it is easy enough to add it later if there is a problem. This really is not a high precision item. Just get a bit of brass the right thickness and get filing.
|
Re: Unimat 3 - replacing/making new gibs
Hello:
toggle quoted message
Show quoted text
On Sun, Jul 10, 2022 at 05:26 AM, Keith S. Angus wrote:
Start with a bit of brass strip the same thickness as the old ...
Yes, that's what I intend to do but I have to get the same/as near thickness as the original or it is honing time for me.
... just a filing job, done by eye.
The gib used in the cross slide is only 50mm long and maybe 5mm x 2mm (have to check). The one on the top slide is even smaller but the gibs on the carriage seem to be rectangular with no special angles. Maybe they will work betetr is they are a bit longer? In any case, I'll try to see if I can come up with a jig to somehow hold the stock steady for filing/grinding.
... can drill or file a recess for one of the screw points, or just file the screws to a sharper point ...
It would seem that the way the screws hold the gib in place can make a difference on whether the gib works properly or not. I still have to give this post a good read and understand what it all means. But first things first, I'll try to get the brass stock and then the size and angles right before I drill anything. Thanks a lot for your input. Best, JHM
|
Re: Unimat 3 - replacing/making new gibs
BTW:
Does anyone know how? to get rid of the extra/unneeded photos?
I deleted the ones that for some reason ended up being either too small or too large but it seems they are still there.
I have noticed I am not the only one that this has happened to.
I ask because they take up space on the server, no sense if they are not needed.
Who takes care of the administrative parts of the forum?
Thanks in advance.
JHM
|
Re: Unimat 3 - replacing/making new gibs
Hello:
toggle quoted message
Show quoted text
On Sun, Jul 10, 2022 at 01:32 AM, Bill in OKC too wrote:
Steel gibs are perfectly fine on cast iron ways.?
Good to know.
I don't know what your U3 is made of.
Hmm ... I'd say it is steel. My U3 has an inscription that reads Fabr. -Nr. 80070243 if that is anything to go by. I have written to the people at Emco asking if they had some idea as to the year of manufacture of my U3. But it would seem that they have some difficulty with the English language and have not been able to get that information from them.
Brass would be fairly good for either ...
Good, because it is probably the easiest material to get for me.
... might be able to fake it long enough ...
I'd rather attempt to do it right from the start. I have learned how temporary things end up being permanent- ish.? 8^/ As I was not getting many Unimat+gibs related hits on the web I opened up the search and came up with a good number of hits. It was rather frustrating as all the videos I found involved the use of some complex tools, specifically very nice, large and powerful milling machines. One of them was a post by the late Merton Baker on [email protected]:
... have replaced deformed/missing gib strips on both a Uni 3 top slide and on a boring head, with brass strips, made narrower than the slots where they go, so as to avoid contact with the stationary cross slide in the first case, and the boring head body in the second. The pockets for the flat point adjusting screws were done with end mill. Actually, a sort of end mill made from a broken tap drill with the point ground flat. Brass is easy to machine.
The thread proved to be very informative albeit daunting as everything seems to requite a milling setup and careful making of the pockets for the adjusting screws. The only possibility for milling I (sort of) have at the moment is a jig I slapped together with parts of an old Dremel drill stand. I purchased it second hand via the local fleabay site years ago but got very little use because it was not at all practical to do anything with it. Using parts from from it, half the column from a modified B&D drill stand and a mounting flange from a modified bench grinder I came up with this:  The mounting flange - in the absence of a decent tool - gave me hell to turn true as the surface hardened due to rubbing from the HSS tool. Not to mention the effect my poor welding skills (hidden by a mix of expoxy and cast iron filings) had on the piece.  ???????????  Eventually I was able to make the surface in contact with the cross slide reasonably true and I expect that the Dremel's vertical is as perpendicular as possible to the table. I then made a temporary "T" nut which holds the table tight enough although I still have to check the rest of the parameters. This "table" travels the whole length of the U3's Z axis and a total of ~ 46mm. along the Y axis which should do. ie: 26mm backwards and 20mm forward, measured from the the Dremel's rotation axis. The Dremel is a model 328, probably the sturdiest model made and @115W and 25K rpm max. it expect it should do a reasonable job. Once I find the collets and bits to get it done and provided I can keep the Dremel mount device from moving sideways. And find a proper way to hold the brass strip tight at the needed angle. I'd appreciate any ideas as to how to hold the brass strip in place and an angle. I'm guessing maybe glued with ciano to a larger piece will do but the angle is a problem. When I receive the new 200W motor for the U3 I'll have a motor for my grinding table and my milling expectations may eventually improve. But for the time being I'll have to deal with this hand. Thank you for your input. Best, JHM
|
Re: Milling with the DB 200
Mehmood,
Yes, the setting of the vertical quill is a bit fiddle. Some day I will come up with a smoother way to set it, perhaps with a lead screw arrangement.
Dick
|
Re: Milling with the DB 200
That sounds good, it would be nice to know if you have any special method for positioning the quill precisely and easily. ?The lever doesn¡¯t give any sensitivity and holding it in one place precisely while re-tightening the quill bolts, is a rather clumsy activity, at least for me.
Regards?
toggle quoted message
Show quoted text
On 10 Jul 2022, at 12:58, OldToolmaker via groups.io <old_toolmaker@...> wrote:
?I use a 2¡± dial travel indicator for accuracy in measuring the vertical position of the quill travel. I can precisely position the quill at any point within its travel making repeatable cuts possible and actually quite easy.
Dick
|
Re: Milling with the DB 200
I use a 2¡± dial travel indicator for accuracy in measuring the vertical position of the quill travel. I can precisely position the quill at any point within its travel making repeatable cuts possible and actually quite easy.
Dick
|
Re: Milling with the DB 200
beetlebud makes a dial indicator
bracket that attaches to the motor mount to solve this problem.
Michael
--
Michael Porter
Michael Porter Marine Design
|
Re: Milling with the DB 200
I have added a drawing to the files - QUILL-SCALE.PDF
This has two possible scale rings that can be used with the quill feed. One is marked 0 - 30 mm in both directions, the other is marked ¡À15 mm. They can be printed onto thick card and cut out - if the central hole is a snug fit on the handle you can zero them like any other scale ring. I tried this when I had my SL and it works well enough. I intended to print one on acrylic with a laser cutter, but then my SL departed, and I never took it any further. I would have added a springy bit in the middle so it had better grip on the shaft, but taking into account how brittle acrylic is.
Just make sure the print is at 100%, not adjusted for paper size. It's nominally A5 (210 ¡Á 148 mm, 8 1/4" ¡Á 5 13/16"), so small enough to fit on most standard sheets.
A more thoroughly engineered fitting is possible, and I reckon working to abut 0.1 mm should be realistic. Calculating the markings is easy enough - the rack is 1 mod, so the linear pitch is ¦Ð, 3.14159 ... and the gear has 10 teeth, so the full circle represents 31.4159 mm (1.237"). The maximum travel is just under one turn of the shaft, so there is no problem with the scale running over 360¡ã.
Thinking about it now, I do still have an SL headstock that needs a rebuild, and I was going to make a new lever for it. Maybe I could do a scale for it at the same time. If so, I'll post whatever I do.
|
Re: Milling with the DB 200
A timely thread for me. I acquired a used milling table for my SL earlier this year. So far I've only used it for drilling but in the past week have been making some extra 'T' nuts so I thought it would be nice to mill the flats on the SL.
For this job I gave up trying to use any 'Z' feed - I just set the 'Z' to the right place once and then locked the quill with the two clamping screws. I then used the side of the cutter, probably stepping over (on the cross slide) by maybe 0.05mm per cut and listening to the noise to decide whether I was asking for too much. For this particular job it had the advantage of repeatability - all of the new nuts were cut to the same 'Z' depth. I had the job mounted on some M6 studding with a normal nut locked tight against it - the flats on the nut in the vice jaws then kept the two cuts parallel.
I'd agree that it would be unwise to ask too much of the DB/SL in milling mode. I always find milling rather stressful - I regard the cutter as actively trying to damage itself, the job, the machine and me. Make sure everything is clamped up tight and then go round and check it all again. Re-check at intervals because the vibration can loosen things too.
I also found that climb milling seemed to reduce the volume of the noise so ended up taking all of my cuts in that direction. This seems to be contrary to the usual advice for small machines but that was my experience.
|
Re: Milling with the DB 200
You can make a scale to go around the feed lever that will give a fair indication of depth, but that doesn't help with repeatable accuracy. You can get digital scales for reading tread depth on tyres that cost very little and could be fitted up for an accurate reading. To control the depth without adding complicated fine feed mechanisms you could add a stop screw, ideally with a nice fine thread, and bring the head down onto it when making a cut. This will be fairly rigid, On the next cut adjust the screw a little and bring the head down to the stop again. A friend used this technique on quite large mills and found it worked well. He would set the stop correct for the final depth and add shims, removing them one by one to control the depth of each cut. It was quicker than fiddling about with dials and readouts, and his main concern was accuracy with speed, since he was on piece work.
|
Re: Unimat 3 - replacing/making new gibs
I have made gibs for a few machines, but not for the Unimats. However, there is nothing too critical about them. Start with a bit of brass strip the same thickness as the old strip, or the thickest you can get that will slide into the gap left when you took the old one out. As you can see on the picture you posted, you need to bevel the edges at 60¡ã to match the dovetail. This is just a filing job, done by eye. The exact dimensions are not critical, provided the strip is an easy fit in the space with all the screws undone. Then just slide it in and do the end screws up until it feels right. The middle screw should be used to lock up the slide when you need to, not for setting the normal feel of the slide. If the strip tends to slide out in use, you can drill or file a recess for one of the screw points, or just file the screws to a sharper point - that will dig in and stop the strip getting away.
|
Re: Unimat 3 - replacing/making new gibs
i done a set of brass stripes and gibs. .yes t would give you more stability Bill in OKC too via <wmrmeyers= [email protected]> schrieb am So., 10. Juli 2022, 06:32:
Steel gibs are perfectly fine on cast iron ways.?
I don't know what your U3 is made of. If it's? cast iron, steel would be good. If it's steel, cast iron would be good. Brass would be fairly good for either iron or steel ways You might be able to fake it long enough to make better gibs in either of the preferred metals with aluminum or plastic gibs the U3 temporarily.? ?Depending on your long term needs you might get by fine with plastic or aluminum while you source better materials even if it takes years. There are harder plastics, too, though some are considered obsolete, like Bakelite that could wore well, or Mikarta.?
Bill in OKC?
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
Hello: I am in need of replacing the gib on my U3's top slide (part 150.190) as it came with a non-OEM of dubious design. The original plastic/fiber molded (?) gibs on the carriage and the cross feed also seem to be in need of replacement. The first one because it is made of steel, not the best material for a gib. The others because of their age but not only that: I am finding there seems to be a lack of rigidity in the cross slide as I practise turning of soft steel. eg: a slow thin surface cut at low speed will cut going in but also coming out. I have looked all over for a source for these parts (unsurprisingly to no avail) but I have not found an article or information on how to go about making a new set either.? I'm sure that the choice of materials, method, geometry, critical dimesions, etc. are of the utmost importance. I did find a couple of photos posted on a German site but only for reference to what had to be done to make the Unimat 3 stay in line, so to speak:
The adjustment bar of the cross slide is made of plastic, not very stable and sensitive.
A small brass strip (see arrow) fixes the problem.
The guide rails of the bed slide are also made of plastic and are too unstable.
Under (low) load, the bed slide twists minimally on the guide prism resulting in an inaccurate turning result.
At least one of these plastic strips should be replaced by an exactly fitting one brass strip to be replaced.
Q: Has any member made a new set of gibs for their Unimat/s? If so, I'd appreciate some input on how to go about it. Thanks in advance. Best, JHM
|
Re: Unimat 3 - replacing/making new gibs
Steel gibs are perfectly fine on cast iron ways.?
I don't know what your U3 is made of. If it's? cast iron, steel would be good. If it's steel, cast iron would be good. Brass would be fairly good for either iron or steel ways You might be able to fake it long enough to make better gibs in either of the preferred metals with aluminum or plastic gibs the U3 temporarily.? ?Depending on your long term needs you might get by fine with plastic or aluminum while you source better materials even if it takes years. There are harder plastics, too, though some are considered obsolete, like Bakelite that could wore well, or Mikarta.?
Bill in OKC?
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
On Saturday, July 9, 2022 at 12:25:01 PM CDT, sawbona@... <sawbona@...> wrote:
Hello: I am in need of replacing the gib on my U3's top slide (part 150.190) as it came with a non-OEM of dubious design. The original plastic/fiber molded (?) gibs on the carriage and the cross feed also seem to be in need of replacement. The first one because it is made of steel, not the best material for a gib. The others because of their age but not only that: I am finding there seems to be a lack of rigidity in the cross slide as I practise turning of soft steel. eg: a slow thin surface cut at low speed will cut going in but also coming out. I have looked all over for a source for these parts (unsurprisingly to no avail) but I have not found an article or information on how to go about making a new set either.? I'm sure that the choice of materials, method, geometry, critical dimesions, etc. are of the utmost importance. I did find a couple of photos posted on a German site but only for reference to what had to be done to make the Unimat 3 stay in line, so to speak: 
The adjustment bar of the cross slide is made of plastic, not very stable and sensitive.
A small brass strip (see arrow) fixes the problem.
The guide rails of the bed slide are also made of plastic and are too unstable.
Under (low) load, the bed slide twists minimally on the guide prism resulting in an inaccurate turning result.
At least one of these plastic strips should be replaced by an exactly fitting one brass strip to be replaced.
Q: Has any member made a new set of gibs for their Unimat/s? If so, I'd appreciate some input on how to go about it. Thanks in advance. Best, JHM
|
Re: Milling with the DB 200
Hello
Slynch:
This is
one weak feature of the Unimat. There is no graduations for
vertical movement. You can move the quill and not loose
location, which you would loose if you moved the milling head.
You could use an indicator to watch how much the quill moves.
Take
small cuts, it isn't a heavy duty machine.
Carl.
On 7/9/2022 9:03 PM, slynch wrote:
toggle quoted message
Show quoted text
I'm fairly new with the DB 200, and I'm trying to figure out how
you mill with it. I can see the X-Y movement with the milling
table attached to the cross-slide, but how do you accurately
control the vertical cut depth ? I don't see any kind of a fine
depth of cut adjustment, or do you re-adjust the milling head on
the vertical shaft every depth change ?
Cheers
|
Re: Milling with the DB 200
Kevin Groenke @ PersonMakeObject
Z-axis in milling set-up is a significant problem. When I do it I use the quill feed on the headstock but accuracy is not inherent. There are some Unis with an aftermarket z-axis feed mechanism out there, but they're pretty rare. Search the group for "UPVLA" for previous discussion of it.? Kevin from PersonMakeObject
I'm fairly new with the DB 200, and I'm trying to figure out how you mill with it. I can see the X-Y movement with the milling table attached to the cross-slide, but how do you accurately control the vertical cut depth ? I don't see any kind of a fine depth of cut adjustment, or do you re-adjust the milling head on the vertical shaft every depth change ?
Cheers
|
I'm fairly new with the DB 200, and I'm trying to figure out how you mill with it. I can see the X-Y movement with the milling table attached to the cross-slide, but how do you accurately control the vertical cut depth ? I don't see any kind of a fine depth of cut adjustment, or do you re-adjust the milling head on the vertical shaft every depth change ?
Cheers
|
OldToolmaker
Bill in OKC too
Carl
.jpg)