Brian

I had to use two layers of 18mm ply to hold up my X2 mill without sagging. You might not need that with the lathe being a bit lighter, but it's better to go for overkill rather than have to change it later.

Also, a firm base gives a better finish to whatever your making.

Bert

My Cl300M which is essentially the same lathe is on a bench from 2×2" timber with a 19mm ply top, and it's perfectly solid BUT the bearing rails under the ply are only 6" apart so very close so rear feet are over a bearer, front feet an inch from the bearer. If your bench only supports the ply at the edges it will be much less rigid.

Neil

Slightly OT – are there any plans around for "standard" workbenches – I need one 2.90m long, standard height and depth, with a G0704-alike mill at one end, about 150kg? I would envisage some sort of angle iron/wood construction

I'm sure designing one isn't hard, but ready made/adaptable plans would be an easier start point.

Thanks
Martin

Hello Brian J

Greetings from Melbourne

To make a strong 2 ply top take the bottom sheet and drill holes with a slight clearance for 30mm self countersinking wood screws, they will not show through to the top if you do it carefully. Place them all around the edges about 75mm apart and 50mm in from the edge. Then liberally coat the drilled sheet and the back of the top sheet with a good coat of PVA Glue, coating both sides of a joint is far better if you want a good bond. Then screw the two sheets together and place them on a flat surface to dry. Place some polythene under them to avoid any spilt glue from sticking your top to something else. almost no glue will stick to polythene, certainly not PVA.

The next day you can sand and finish the edges of your top.

To finish the top use one pack polyurethane, I like the solvent not water based type…. The first coat will be sucked in. when that is dry apply two more coats sanding between each. lay them on thick, really thick, with a brush, do not spray or you will get bubbles. Brushed on then carefully laid flat with the brush it will look like a glaze. You can build the coat up to over a mm. The material will not craze or bubble as long as the previous coat was dried, follow the instructions on the tin. You will get a very durable finish. most solvents will not affect polyurethane. Obviously you will need to avoid piercing it down to the wood exposing it.

After the last coat has dried overnight it will be ready for use however It will not be fully hard for about two weeks, at which point it is very hard, not as hard as Laminex or Formica but not far off. 

In a previous life I ran a manufacturing business making furnishings, all our cutting tables and workflow benches around sewing stations were made using this method, in this case we used a single layer of 18mm MDF with rounded hardwood edges not plywood. The tables and benches were still in good condition after over 20 years of continuous use.

No we were not working with steel which is more abrasive so the life will be shorter but it is very easy to refinish when needed, just sand back for a key and paint.

We liked this method because it gives a nice consistent golden timber colour to the surfaces, we used it a lot around the place, it made it a pleasant work environment. we always had a tin on hand.

OK under a lathe it may be a good idea to stain the timber black or grey before you urethane coat it, to make the grunge that will fall on it less noticeable.

Regards
John

Edited By John McNamara on 19/06/2014 14:40:17

Edited By John McNamara on 19/06/2014 14:48:49

Martin – for a bench design copy a kitchen unit BUT only use plywood not chipboard or MDF which has sod all structural strength. This design has many advantages over the traditional 4 legs and braces type since it has the diagonal braces built in as it were and can easily be fitted with drawer runners.

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Because, if they are to act as one piece, there must be NO slippage between the two.

• Two independent sheets will only have a bending stiffness of twice one sheet.
• But one sheet, twice the thickness, would be for times stiffer than one thin sheet.
• The better the bond between the two sheets, the closer it will approximate the second condition.
• … read-up on "Moments of Inertia" if you need to.

Try experimenting with some narrow strips that you can bend in your hands.

MichaelG.

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P.S. Moments of Inertia are not just the ones I spend in the Armchair

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Brian,

Apologies … I should really have referred you to "Section Modulus"

MichaelG.

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Edit:  … Sam,

I think you will find that Bending stiffness is proportional to the square of the thickness, not the cube.

Edited By Michael Gilligan on 20/06/2014 07:44:24

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Make that … " not going to do as much "

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Corrigendum:

Please ignore the quoted posting … ^

Sam is, of course, correct and my 06:18:07 posting needs revising:

MichaelG.

Michael does this not greatly depend on the quality of plywood used, density of layers, so many factors these days to consider.

I must ask by double layer what thickness are you defining 30mm each or over all??

I have a double layered CD ply workbench top which a fellow made (he made the whole bench to house his C6. He moved interstate Tassie, I scored well). This is coated with a number of layers of lacquer it takes a pounding mainly used for wood work. Small indentations have come about over time.

I am considering making a bench to go under the ML7 (ML7 is on a 2x2x1/4 angle frame) roll out and it will be used as a mark out and general bench for lathe work and tools storage.

I am considering Ply a reasonable quality I can get a hold of double layered or 40mm MDF. The problem is of course moisture and keeping it out.

http://www.model-engineer.co.uk/forums/postings.asp?th=97051&p=2#PostTop

Brian John I saw these or similar frames at Masters (https://www.masters.com.au/product/101027085/amazon-upright-900x600mm) and they sure look sturdy and strong.
My son worked for another company who makes similar but were shelving (Delta Shelving) using 1x1x11/8" angle and I have these for storage in the workshop.

Reply To: Yet another one from Yorkshire

Hare & Forbes have a nice range also if the first would take the weight of the ML7 I'd be seriously looking at buying that. https://www.machineryhouse.com.au/Work-Bench