New Gib For Me Elliott 00 Juniormil

Hi all, I am new to the forum so please excuse any cock up's.

I purchased an Elliott Juniormil in the latter part of 2015 (Which incidentally was a complete wreck) but now almost finished. I say almost because when I bought the machine it came without the Gib that corrects the bed (or Y axis if you prefer).

As there is no gib that came with it I can't measure the old one. does anyone have the dimensions for this mill. the mill bed is on the bench at the moment and makes it an opportune moment to tackle this job. Thanks.

I would appreciate any help or advice

Edited By Ian Allgood on 26/06/2016 08:22:03

It will be as long as the sliding part? Longer would be pointless and likely to foul something; shorter would decrease its effectiveness - think here if it was so short that the adjusters did not act upon it!

Thickness should be the maximum that can be accommodated - no point in making it thin and flexible.

The angles and width will be that of the current dovetail with a little clearance. Just pay particlar attention to clearance in the topcorner to avoid pressure on anything but the flat surface. Depressions for the adjusters to positively locate and allow adjustment might need some consideration re size shape and depth.

I would be looking at the long travel gib to provide clues. There is a distinct likelihood that the two gibs are similar.

There is an Elliott group on Yahoo Groups but as above the form is kind of obvious. You could make it out of brass rather than cast iron as the cost is still low in comparison to the value of the mill, or steel if the x-axis is steel then probably that's what the original was.

Hi Ian Allgood

An interesting problem.
Edward F. Connelly's book, Machine tool reconditioning deals with making taper gibs however he suggests using the old one as a pattern, that in this case is not available.

The question is how to make a pattern, I wonder if this would work?

First clean the dovetail and the opposing dovetail on the main casting where the Gib bears.
Then with a small hand plane shape a piece of fine grained wood by introducing it into the hole and planing off the marks left on it by the casting bit by bit pushing and planing until it is fully within the hole. Once the fit is almost there you may need to switch to sandpaper on a hard block.

The piece of wood should be a (lot) longer than needed this will allow finer and finer adjustments to be made to the fit tapers are very deceiving. If insufficient marking is made by the cast iron, bluing could be applied to the taper to mark the wood when it is inserted.

The table should be located and ideally clamped to the opposite side of the gib dovetail.

The wooden template should enable a copy to be made in cast iron or brass, it will not be perfect but using the same scraping process as used with the wood (In this case using a scraper not a plane) the over long piece of metal could be brought into perfect bearing.

If the machine was a wreck the dovetails may be worn I would not cut the taper Gib piece to length until the travel of the table was checked for accurate sliding. All the 3 dovetails that slide may need scraping back to spec. Preliminary inspection should be made with a straight edge.

Regards
John

Edited By John McNamara on 26/06/2016 15:18:49

Try this if it helps - it's the long one but it might help you

Mark

Hi All, Thank you for replying, all interesting ideas. John, Your idea sounds very good to me I may even try it. Maybe a piece of hardwood would do best. I see only one floor in your plan, me and wood are not friends it doesn't like me and I don't like it so we stay apart but if that's what it takes then I'll have a go.

Mark, thanks for the drawing I have downloaded it and I'll take a closer look later. I got my homemade hoist out and took the bed off and turned it over and in a spurt of inspiration, using a couple of bits of silver steel I had, I managed to get the taper angle by measuring the back and front of the dovetails I then drew it in TurboCAD and measured the angle. Whilst writing this I just had a thought if I put marks drawing into TurboCAD I can merge the two and check the angles.

Ian

Ian,

If you look at my drawing it should have all the dimensions you need to draw a copy and compare with your measurements. If it helps I can email you a dxf file that will open with the actual geometry but you need to send me a message with your email in for attachments to work (they don't allow them on here).

What I should have made a point of was that the angle is 1 degree relative to perpendicular planes for the dovetails. In other words, if they cut the dovetail with a dovetail cutter the "straight" side is just that but the cutter then travels on a taper of 1 degree for the gib side. It took me ages to realise this as I was expecting a 1 in 40 taper or some other standard machine bed taper but I kept getting the odd angle as I was measuring across the tapered faces - you have to measure them at 45 degrees (in the case of the Elliot) to get 1 degree.......

To measure the angle you really want to use rollers and a 2 axis system - perhaps slips between the rollers and perhaps a depth micrometer or vernier for the displacement down the way?

Anyway, making a new one should be easy if you set up your blank against two pegs and cut it with a dovetail cutter. Then insert some shim the correct thickness between one to give 1 degree and cut the other face.

Mark