How many clamps needed for table top?

[fobos8]

Hi all

When gluing up a table top 1600mm long by 900 wide ( made up from 8x2 oak ). How many clamps should be needed to do a decent job?

Want to make sure I've got everything ready before I start.

Secondly Pony pipes or Bessy K body - which is best?

Best regards, Andrew

 

[big soft moose]

work out how many clamps youve got then add 4

seriously, are you talking about gluing up the frame, or gluing up a veneered / strip surface ? - for the former i'd reckon four sash cramps while for the latter it would litterally be everything youve got - minimum 4 pairs with cauls but more would be better

 

[wizer]

I think K bodies are more versatile and a little lighter than ponies. You want a clamp every 12inches or so, IMO. You can get around it with cauls, etc

 

[fobos8]

I'm talking about clamping 5 pieces of 8x2 planed oak biscuit jointed together.

I've only got two clamps long enough so will have to buy some more.

I reckon you can get more clamping pressure with the ponies and you can just get a long piece of pipe instead of a new clamp.

 

[wizer]

8 inches long? You only need one additional clamp IMO. If you didn't want to do that then there are work arounds.

 

[big soft moose]

I'm talking about clamping 5 pieces of 8x2 planed oak biscuit jointed together.

I've only got two clamps long enough so will have to buy some more.

I reckon you can get more clamping pressure with the ponies and you can just get a long piece of pipe instead of a new clamp.

okay - well i'm no expert but i think you want a cramp at every set of biscuits so assuming they were at 8 inch centres that would be 8 cramps.

 

[TheTiddles]

It's a very open question, if the boards are dead straight and the allignment is perfect maybe two or three will do, if you end up ramming them together to get round slight gaps and add more to allign them vertically you'll need loads. You can do it with two by making big cauls which could be fun from B&Poo pine and you can shove them in the loft or similar for future use as elephant skis

Aidan

 

[Paul Chapman]

8 inches long?

Keep up, Tom - it's 1600mm x 900mm :lol:

You really need quite a lot of cramps, which can get quite expensive. Another option is cramp heads on wooden bars, to keep the cost down.

One thing to remember is that all sash cramps bend a little as you tighten them, so it's best to alternate them - one underneath, one on top and so on. Also, if you shape the cramping blocks, as in this picture, that helps to direct the pressure towards the centre of the workpiece and counteracts the bending of the bars, helping to ensure that the piece remains flat

Hope this helps.

Cheers :wink:

Paul

 

[fobos8]

will definately alternate them.

Its my first job so I can't imagine joints will be bang on. So if I go for one every 12 inches (300mm) that will mean I'll need 6. 3 on each side

How does that sound?

Anyway whilst we're on the subject what is the difference between a clamp and a cramp?

I thought cramp was something you get when you hear a good joke?

 

[Paul Chapman]

12" spacing sounds OK. Some people say "cramp" and some say "clamp" - there may be a technical difference, but for all practical purposes they mean the same thing.

Cheers :wink:

Paul

 

[Dibs-h]

You really need quite a lot of cramps, which can get quite expensive. Another option is cramp heads on wooden bars, to keep the cost down.

Paul

Where do you get them from out of curiosity? (not that I'll be needing any - for a long time :wink

 

[Mattty]

The rutland's record copies are quite good. Not as good as originals but 7/10.

 

[Paul Chapman]

You really need quite a lot of cramps, which can get quite expensive. Another option is cramp heads on wooden bars, to keep the cost down.

Paul

Where do you get them from out of curiosity? (not that I'll be needing any - for a long time :wink

They are Record #130. They are still available but the design has altered a little - they now have longer threads. There are other makes available from Axminster and Rutlands and probably other places.

I've been using them quite successfully since 1970. I've recently got some Record #135 all metal sash cramps, which are much better, but the cramp heads enabled me to have lots of sash cramps at relatively little cost when I didn't have much money.

Cheers :wink:

Paul

 

[OPJ]

Those sash cramp heads are a good investment and you often see them pop up on eBay. A few moths ago, there was even a seller selling two sets of the modern Record ones for a very good price.

I've got a few of the old ones with the shorter thread, which is the only real downside to them. On one of the modern cramp heads I own, as you tighten the cramp, the head pivots or slides; it doesn't provide firm pressure - I think the thread may be bent slightly. :?

My only other word of advice with these would be to oil/wax the wooden bars. Otherwise, you may find they become glued to your table top and you literally have to rip them off!

 

[woodbloke]

One cramp every 300mm or so and alternate them, one under, one over (as in Paul's pic) Also glue up the boards one pair at a time...don't try and pull up the whole 900mm's worth in one hit - Rob

 

[wizer]

A couple of cramp heads got me out of a hole the other day. Very useful to have in your bag of tricks.

 

[Dibs-h]

Those sash cramp heads are a good investment and you often see them pop up on eBay. A few moths ago, there was even a seller selling two sets of the modern Record ones for a very good price.

I've got a few of the old ones with the shorter thread, which is the only real downside to them. On one of the modern cramp heads I own, as you tighten the cramp, the head pivots or slides; it doesn't provide firm pressure - I think the thread may be bent slightly. :?

My only other word of advice with these would be to oil/wax the wooden bars. Otherwise, you may find they become glued to your table top and you literally have to rip them off!

There's a place local to me - who sold me some 4' sash cramps for what seemed like al ridiciously low price some yrs ago when I made a staircase. Recall the price being around £10 each. Chinese copies of the orginal Records - but very sturdy.