Lamination grinder (hardly a traditional craft)

[gilnockie]

Here is a link to a thread I have created on the Leatherwall which shows the lamination grinder I have recently built:

http://leatherwall.bowsite.com/TF/lw/th ... =3#2291067

[nimrod]

mate followed the link opened ok BUT I now have to be the one that doesnt understand how this works what moves the the grinder or does some thing else slide along sorry if this is a stupid question cheers

[gary p]

hi , you very cleaver man , i will make one for my self ,i have a linisher already . my only concern is that when i have used my linisher on wood before it tends to burn the wood because it spins too fast. thanks fo the idea gaz.

[GrahameA]

Morning Norman

So when is the write-up on the "Home-brew Carbon Lams"?? Or did you do one back down the line??

Why do I see work ahead for me..

[greybeard]

Hi Gary,

I have a similar machine which is mounted vertically. A pivoting side fence allows for different lamination thicknesses as well as tapers.

A 60 grit zirconia belt gives a good gluing surface and the only time I experienced 'burn' was if I tried to remove too much wood in a single pass or the belt was worn out.

Daryl.

Let me know if you would like a photo of the setup and I will email it to you.

[gary p]

hi daryl, i would appreciate a look at your grinder thanks mate, gaz.

[Coach]

Let me know if you would like a photo of the setup and I will email it to you.

Whack it up here for all to see ,, I am sure a lot would like to see it

[greybeard]

Here are the photos.

I did not post them earlier as I did not want to hijack gilnockies' thread.

The setup as shown in the photos is for parallel laminations and I have a master block for tapered laminations which is used in conjuction with the fence.

Daryl.

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[nimrod]

thanks for posting the pics that I can understand cheers

[gilnockie]

Hi Nimrod

The belt sander is an attachment which which is made here in Australia. To attach it to the bench grinder you remove the right hand cover and the right hand grinding wheel.

You attach an adapter plate to the bench grinder and then attach the belt sander to the adapter plate.

Here is the video from You Tube which shows how to attach the belt sander to the bench grinder:

http://au.youtube.com/watch?v=DVujiTB9ftc

You adjust the angle of the belt sander from below horizontal to upright, depending on your needs. You are then able to sand wood or grind metal according to the belt you use.

The bench grinder turns the grinding wheels toward you so that sparks are directed down below the wheel and away from you. You use the sanding belt in the same way.

How do you use it to grind laminates?

I built a ramp which sits below the sanding belt attachment. It is fixed at the far end with a butt hinge. I fitted a winding device to the front of the ramp so that I can adjust the gap between the underside of the belt and the ramp by a few hundredths of a millimetre at a time. I fixed a batten on each side of the ramp so that it would not move sideways. The springs near the winder keep some tension on the ramp so that it does not vibrate up and down.

I set the initial gap between the belt and the ramp so that I can move the sanding belt with the laminate, using a gentle pressure on the laminate. Then I remove the laminate, turn on the bench grinder and move the laminate through the gap.

So to answer your question as to how it works: you adjust the gap between the sanding belt and the ramp so that it is fractionally too narrow. You then pass the laminate through the gap, from the front of the bench grinder, at a steady speed. When this is done, you measure the thickness at several places along the laminate, on both sides and compare the actual thickness with the required thickness.

You do this several times until the laminate is the required thickness, being careful not to remove too much material.

A few hundredths of a millimetre too much or too little will mean that draw weight of the bow will be too light or too heavy by several pounds.

On Saturday I needed a laminate which is 1.85mm thick. I ground it down from 2.2mm to about 1.86mm in about 10 minutes. To do this by hand normally takes me two hours.

[gilnockie]

Hi Grahame

Here are the threads:

First the buildalong: http://leatherwall.bowsite.com/TF/lw/th ... &category=

Second the discussion: http://leatherwall.bowsite.com/TF/lw/th ... &category=

[gilnockie]

Hi Daryl

No problems with posting your photos. It is interesting to see how you have used the same basic components to arrive at a different solution.

I like the way you have built a shroud to catch the dust.

[nimrod]

norman thanks for the reply cheers

[GrahameA]

Thanks Norman.

[greybeard]

Although not perfect the shroud catches about 90% of the dust.

If anyone is contemplating building lamination grinders similar to those shown don't skimp on the hp of the bench grinder. I am running a ¾ hp heavy duty grinder but a 1 hp would be better. Shop around and find a grinder without all the fancy attachments or is a discontinued model to save money.

When feeding laminations through the grinder it is important to maintain a constant feed rate, if you momentarily slow down you will get low spots.

The grinder is also useful in shaping handle sections.

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Daryl.

[yeoman]

Try as I might,I cannot find a source for a multitool attachment.

Where in oz can I get one, and how much will I be out of pocket?

Dave

[Graeme K]

Try Hare & Forbes on line . GKL

[Steven J]

Dave,

I am now on the hunt also. I'll let you know how I go if I can find a source. I have seen the 50mm wide model in Bunnings (around the $130 mark). I would like to get a wider model if possible as I would like to have a crack at recurves one day and pyramid bows.

I think I might try and develop a system that can flip the unit from horizontal to vertical.

Steve

[longbow steve]

Hi Steve, I used a multitool to begin with, mounted above an old drill press rise and fall table. Worked well but you need to keep the lams moving at a steady speed to avoid low spots in the lam. Steve

[Gringa Bows]

very good ideas Gilnockie and Daryl,how fast would you put the lams through the grinder and how much meat do you take off at a time...........Rod

[gilnockie]

Hi Dave

The Multitool is distributed by JW Ross. Here is a link to their home page: http://www.jwross.com.au/

On the home page you will find a link to retail outlets and also a link to their catalogue. There are other models of the multitool, one of which may suit you needs better than a 50mm belt.

I bought mine to grind lams 35mm wide. That is its only purpose.

Mine cost about $190 as I recall, but you will probably pay less on the mainland.

For anyone who buys one, here is a tip: the sanding belt supplied is much better for grinding lams than an off the shelf equivalent. because the thickness of the belt is constant. An off the shelf belt uses a lap join which varies in thickness.

Finally, the multitool is the only device I could find which bolts straight on to a bench grinder.

[gilnockie]

Hi LB

The slower the speed across the belt, the more material you will remove.

I concentrate on a constant speed, light sanding pressure and frequent measurement of the lam thickness between passes.

The belt travels so quickly, it is easy to remove too much material.

[greybeard]

Hi Rod,

Trial and error.

When I initally set mine up I got a length of 1800x38x19 mm pine and cut laminations and put them through to get the feel of the machine. When you cut laminations from your billets you usually end up with a strip off the edge you can use for a test run.
Generally, if you try to take too much off in a pass you will hear the motor starting to labour.

Daryl.

[Gringa Bows]

this is a couple of drum sanders i'm trying to set up for doing tapers do you guys think they will work.

[greybeard]

Hi Rod,

Is the drum sleeve sander in the first photo of the pneumatic type? If so I haven't used one but there is no harm in trying it.

The drum in the other photo looks like the ones with a wooden core and sleeved with soft rubber approx 4mm thick.
I have tried the 75mm one on a vertically mounted bench grinder [the bottom of the drum being a couple of millimetres below the bench top] and at the higher speed when feeding laminations it caused the soft rubber to distort and bulge on the feed side.

You may also find the drum will not handle coarse grit papers which yield a better gluing surface. Having said that I found it was good for thicknessing buffalo horn. With an adjustable guide about ¾" thick and having a semicircular end allowed the feeding of the curved horn and you could grind both sides.

You need a drum that will not distort under load and maintain an even grind across the lamination.

If you already have the components try them on scrap timber and evaluate the results.

Daryl.

[Gringa Bows]

thanks Daryl,the first one is pneumatic mounted on an 8in. grinder i will give it a go i've just went and found some pine i can experiment with,and the other is what you said, i have played with it and the lams.turned out a bit ripperly may be i fed it to quick,if niether work i will try a multitool

[gilnockie]

Hi LB

Can you post some pics of how you attached the sanding drum to the bench grinder shaft.

Can you also describe the sanding drum and provide some info on who made it and where you bought it.

[Gringa Bows]

gidday Gilnockie,it's an 8in. grinder,the drum sander is 110x150mm it scews on the left side and is left hand thread ,mine has a threadedshaft adapter so its a bit further out from the grinder.

i got mine from a local tool shop it was in a carba-tec catalog.

[looseplucker]

I use a drill press with a drum attachment and a gate which works very well provided you don't try to take too much off at a time - which can not only cause burning but undulations in the wood, which are a pain to remove.

Mind you, I really like the look of Gilly's machine...nifty piece of kit.

[Gringa Bows]

i've just bought a multitool gizmo so i'm going to set it up and see how it goes in the next week or so