How I made 55° gib strips for my Sieg X1

[Russ BParticipant @russb]

aka SX1 SX1L same table on the X2P and X1LP

[Russ BParticipant @russb]

A chap who goes by the Alias Toolgrinding has asked me via PM how I made my 55° gib strips for my X1 back when I owned one. I thought I'd pop the answer down in a thread so its open to all as I don't think I've seen it done like this- I'm using what I've got, which is just a 4mm endmill, and a standard T slot clamp kit + the appropriate size spanner, and piece of wood to protect the machine table – oh and a calculator or a good head for numbers, if you've got a spreadsheet program you can probably use that to work out the numbers.

This is just my way, I don't have any of this sort of industry experience, I'm just using my head, I'm sure there's room for improvement.

I recall many people were cutting a groove in a bit of wood, then glueing the strip in and machining it. I didn't have that option all I had was the mill itself, so I had to make do with that, the results were very very good.

I measured all 3 gibs, they were all the same thickness – the Z looked thinker – but it wasn't it was just a few mm shorter. so I bought some brass flats the appropriate size – slightly thicker than the ones fitted, as I was confident there was room – 1/8" if I recall, but I suspect this could easily change from one machine to the next or even one gib to the other.

I fastened the strip down to the table and aligned it to the X axis with the DTI (it was sat on a piece of old laminate floor board to protect the bed.)

I then took a small 4mm ball nose cutter and calculated the combined Z and Y movements required to machine the 55° angle through the strip and well in to the laminate (minimum 2mm to pass the ball nose) – I calculated about 6 steps.

Zero'd the Z and Y to the edge of the strip facing me, and started a surface pass far enough back to allow the cutter to drift forwards and down, forwards and down, and again and again, by the values I'd already worked out to create the 55° slope. (ie, I move Y, lower Z lock Y and Z, and then feed X the full length of the strip, and go to the next Z,Y positions)

I deburred & flipped the part and repeated – this time zeroing on the rear of the strip and again, back to the calc sheet to then work out how far forwards I need to start the cut in order to get the correct height strip (they were all slightly different on mine, and again, I made them slightly larger than the existing ones to be a better fit.

Once trimmed to length I did a quick test fit and blued the end of my already made ball ended adjusting screws to mark the 4 locations that I needed to spot face the strip – you should really take care here, if you drill to high or low, or have differences between the holes height or gap you could distort the strip – you might find it works to just not bother they will make their own mark in time at a guess.

I then planned on hand filing the steps out, but they were so close I just left it, I don't think the top and bottom edge are doing much anyway

The hardest part was measuring the geometry required, I seem to remember I had to remake the Z strip.

Care must be taken no to overtighten the strips, as you probably won't notice if you do. It will obviously wear much quicker than a steel strip but I found I didn't have to adjust mine in the all the time I had it (a year or 2?)

I hope that makes sense, fire away with the questions if you want –

Toolgrinding, I think I kept them when I sold the machine, if I can find the old strips in the garage (if they've not been recycled!) then I'll let you know, you can have them.

[Peter G. ShawParticipant @peterg-shaw75338]

Recently I made some new gibs for the Warco MiniMill using an idea suggested by Harold Hall. I used steel of an appropriate size, then scraped one side flat: this being the sliding side. To form the angles, I placed the milling machine saddle in the vice and clamped the embryo gib against the relevant dovetail using a rod and engineering clamps. I also made some sacrificial covers for the dovetails and then filed across the saddle until the angles were formed, turning the embryo gig occasionally. Using sacrificial covers meant adding packing under the new gibs to allow for the extra height. Also, I allowed a small gap between the edge of the new gib and the sliding part of the dovetail: the other edge moves with the saddle.

Each adjusting screw was a 6mm grub screw with a dimple in the end to sit on a 4mm steel ball. To mark the correct location, I first made a hollow grub screw with a 4mm hole down the middle. I then clamped the new gib in place on the saddle, inserted the hollow grub screw until I felt it touch the gib, and then locked it. The saddle was then positioned under the vertical drill, and a 4mm drill inserted in the hollow grub screw until I felt it touch the new gib. I then drilled a 2mm deep hole, which is really just the cone part of the drill. Hence the 4mm ball sits in the cone in the gib, and is held in place by the proper adjusting screw.

I didn't have to measure anything, or calculate anything and the result is far superior to what was done before.

Regards,

Peter G. Shaw

[IanTParticipant @iant]

I've made gib 'pieces' for small tools and fixtures occasionally and used the method described by Martin Cleeves in ME many years ago. I've posted this idea before but in case some haven't seen it, please forgive the repetition.

A length of Hex rod is drilled & tapped on one face to taking clamping bolts. The bar is then screwed to a faceplate with the clamping face at an angle (60 degrees in this case) to the faceplate surface. The gibs to be machined are either clamped or directly bolted to the Hex bar and aligned using a DTI or simple pointer on one end (and swinging the work through 180 degrees).

The work is then simply faced to the required depth. It's actually quite quick and very simple to do. Small slides can be easily made using this method. I'm not sure how critical the 5 degree difference would be in this case – but not much on a thin strip I'd guess. I think I'd probably just adjust the width of the strip slightly. You could also use this method on a mill table of course.

Regards, IanT

PS I don't seem to be able to get the photos in the correct order but I hope the idea is clear enough

Edited By IanT on 28/09/2014 10:16:05

[TrevorKParticipant @trevork]

Russ

Thanks for setting up the thread in reply to my PM, its generated some useful alternative methods to the one I was going to try first so I'll set my woodwork plan aside for now. Peter, Ian, thanks for your input . I'm off to Polly for some brass strip.

[Russ BParticipant @russb]

I've found my strips so if you want something for nothing, let me know and we'll work out how to get them to you.

The Z strip isn't right for reasons I don't remember – it will work but the rear face has a groove down it's full length which takes one of the acute corners off. I think the stock was recycled from something else and I started machining it from the other side, thinking I'd missed it. I can now see the strip is worn mostly on the diagonally opposite acute edge so the notch is allowing it to tilt slightly when tightened.

As its the shortest strip it is an ideal candidate for either 2 of the alternate methods described here.

Thanks to Peter and IanT we've now got a lathe method that will also be suitable for horizontal or vertical mills and a hand tools method. I think that gives people plenty of options if they don't happen to own a large table saw capable of cutting a groove the correct width, depth and angle out of a piece of wood- which I suspect is probably most people!

[IanTParticipant @iant]

I've never examined an X1 closely Russ and I wasn't certain exactly what the 'gib' arrangements were but if Martin's method is useful, then that's good.

It occurs to me that some reading this might not know the difference between gib "strips" and gib "pieces". Older machines often had solid gibs (there was no "strip" as such) that directly bolted to the main assembly. They still needed some form of fine adjustment but once set, solid gibs keep their adjustment very well (they don't flex or move). In some ways gib 'strips' are a backward step but I guess are simpler to (mass) manufacture (less parts?)

However, for anyone making 'custom' slides (especially those with limited resources) solid gibs are easier to build in my view. No need to machine two matching dovetails – requiring dovetail cutters. Gib pieces can simply be screwed to a flat surface, although another plain (fixed) strip is required to take the adjusting screws for the movable piece. Where greater strength is required, the gib pieces can be set in a simple milled channel with the adjusting screws tapped into one edge of that channel. This is the way many lathe and mill slides were built at one time.

Martins method will of course work for 'strips' too but I think I'd sandwich thinner material between two (sacrificial) clamps and avoid any holes in the strip!. Hope this is of interest.

Regards,

IanT

[Russ BParticipant @russb]

Sorry Ian, you've lost me a bit

Do you mean like the Gib on a Myford Super 7 top slide vs an ML7 (perhaps just the early ML's?), where on the Super 7 the gib piece actually forms the angle and is fixed to the topslide vs the ML7 where it "floats" on top of the locked adjusting screws – for the benefit of others: On the Super 7 only one side of the top slide casting has a machined dovetail, the other side (the adjusting side) is machined plain at 90° with no angle and has the usual tapped holes in the side for adjusting screws but then has 4 countersunk holes in the top Tee sloted faced for securing and locking the gib once adjusted. The gib which is rather large (much thicker than it is tall) forms the dovetail, its rear face (the one the adjusting screws bear on) is flat – exactly like the one your're machining in your very own 50's Super 7 in your photos

(Same as mine !)

The screws in the top that secure it must be loosened and then just nipped slightly tight so the gib is loose enough to adjust, but not loose enough to float about.

Also on the super 7, the adjusting gib, is actually 2 gibs, each having 4 screws, a pair to lock through the top, and a pair through the side to adjust – essensially they act as one large gib.

The ML7's have angles machined on both sides of the topslide casting and is just slightly wider than the dovetail on the carriage thus the strip is just a thin flat piece almost the exact same setup as the Sieg X1 slides.

The Super 7 method requires a wider topslide casting (or a thinner dovetail on the carriage) to accommodate the wider gib etc – thus the same amount of space could house a wider dovetail if the thin strips were used – but which is stronger……  swings and roundabouts?? – oh, and then there's tapered strips to think about, which personally I prefer, although they do require a more precise fit as well as meaning the opposing sides of the dovetails are not parallel – which must be a pain to machining accurately when mass produced on a budget.

Edited By Russ B on 29/09/2014 14:50:46

Edited By Russ B on 29/09/2014 14:51:41

Edited By Russ B on 29/09/2014 14:54:33

[Russ BParticipant @russb]

Edit, edit edit edit, I'm always editing!

I need to get one of those dog collars that deliverers a shock whenever they bark – reprogrammed to give me a jolt whenever I edit something, that'll teach me…….

This is what happened when society moved from hand written words and drawings to electronic methods – or perhaps, and to be honest, far more likely: I'm just a bit thick.

[Russ BParticipant @russb]

The numbers I had worked out, to create the 55/125 angles were 0.42 Y to 0.6 Z. (I halved the step on the long X axis to make it smoother, as it was a bit long to accurately file flat by hand)

Since these numbers are only of use to someone who's either a beginner or perhaps doesn't come from an engineering/maths background the following advice seems suitable,

If you zero on the front of the strip which is aligned to the X, move your cutter back by the thickness of the strip – this will ensure you don't run out of stock as you cut forwards and lower repeatedly to form the angle .

When calculating the length of the face of the strip required try not to measure from the radius'd corners. You will need to know this length, as when you flip the part, align it, and then zero on the back sharp newly formed (and not yet filed down!) angle you'll need to know how far forwards to move and then add the tool diameter so you finish with the correct size part. – the Z is stubby compared to the X and Y on the X1

So you want hold the strip at 55deg in your calliper and measure the height (rock it slightly while applying light pressure on the calipers to find the flat spot – its a bit of a handful…….)

Then basic right angle trig will tell you the true length of that face, no need to guess where the chinese style unevenly deburred corners once were – the angle of the strip is 55deg, so the angle used for calculating the triangle will be either 35deg or 55deg depending which way you attack it – if when you solve the triangle the measurement you took is the smallest of the 3 sides – you used the wrong one of those 2 angles… so use the other the side your interested in should be the longest of the 3 given, the side you measured being the middle of the 3.

I also measured the size of the slot, which on my machine was much larger, I met half way and made it a bit taller – but still a very loose fit so it doesn't interfere with the mating between saddle and base.

– sufficiently mind numbing for you?

Measure twice, cut once….. and then mess it up anyway like I did – oh yeah, about that DONT use ball ended cutter it's really complicates calculations as you then need to work out offsets to calculate which part of the arc will touch the work piece – just leave it out, use a straight endmill with no visible corner radius.

I said arch instead of arc – ZAP!

Edited By Russ B on 29/09/2014 23:14:59

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