Laminated Bow info.

[hunterguy1991]

Ok guys, we've probly had this conversation before but I'd like to get a few more ideas on Laminated bows (long and recurve).

There will be a list of questions and queries hopefully I can have answered.

Firstly I have found a supplier of many different timber species which is relatively close to home by the name of Lazarides timber (check out their site http://www.lazaridestimber.com.au/ ). As far as limb core laminations which is the best timber to use. I know the big companies(Bear, Hoyt etc) use rock maple which Lazarides do carry as an imported timber.

Second, I have been informed by some of the more experienced guys on here that its best to use tapered laminations in the limbs, usually 1 in 1 thou of an inch, however, I have looked over a few different recurve bows (dads old hoyt pro hunter, a mates Bear grizzly) and noticed that neither of these bows use a tapered lamination in the limbs.

The Hoyt has a back and belly lam, both of which are a constant thickness (0.0705") their entire length which come together in the limbs between black glass.
The Bear Grizzly is different in that it only has a single piece forming the limbs between black glass. I don't know the thickness, id be guessing its around 3-4mm but again, there is no taper.

Do the recurve makers on here taper their laminations? These two bows are examples of working bows with no taper so obviously it does work... Would it be worth a try as Im without a lam grinder.

I think this is my last question (for this post at least), for a bow (either recurve or long) of a desired draw weight of around 50 lb, what thickness glass would be used? Is there a chart or general rule as to draw weight vs glass thickness ( I'd like to know them all, 0.003 up to 0.005 so I can use different glass in different desired draw weights.) I have read in other posts that 0.003 glass will yield bows up to 30lb or so.

The info you guys provide is very much appreciated but remember I'm new at this and just trying to get my head around it all so be nice...

Straight shooting,

Colin

[bigbob]

The matter of taper rates on laminations is highly debatable and one that most people will have a differing opinion about the pro's and cons of their particular preference. With recurve limbs being so wide relatively speaking one can get the required performance by tapering the width rather than the depth. HH style long bows tend to use tapers in the lams as they are rather narrow in design. Still, quite a few makers only use some tapers combined with parallels. M y personal preference is all tapers for the smoothness of draw and absence of 'stack', and the only thing to watch out with that preference is if the design becomes whip tillered , ie; if the tips approach 90 Degrees at full draw making an acute string angle at the nock grooves. I think it all comes down to what each bowyer has experimented with and decided was the best for him.

[greybeard]

Colin,

If you are only building one or two bows have you considered purchasing the Bingham kits, it could save you time, money and frustration the first time round.

Daryl.

http://www.binghamprojects.com/firsttimebowyer.pdf

[hunterguy1991]

Gday Bob,

firstly, your always quick to provide thoughts on my posts and for that Im very grateful!!

Secondly, you hinted at there being less a need to taper lams in recurves. Would this mean I could have a decent crack at making one with straight laminations (and hopefully have a success)?

Any more info regarding the timber to use in laminations (my suggestion of Rock maple perhaps) and the glass thickness. I can order some glass from Binghams without any problems and may be able to get the timber supplier to cut the limb laminations at a set thickness when I purchase them.

I have a good stock of Techni-glue and would be making a one piece recurve (should I have a go at it) so there would only be a few lines of glue (glue up shouldn't be a problem) so this leaves me with the form as my last issue.

I do wish to make several bows so I think the air tube is the way to go, however Im unsure as to how to go about making the form for a bow. I have some rough ideas on how its done but are there any build alongs for bow forms on here that could assist me??

Or perhaps someone could give me a run down on here via PM or on this post. Im well aware that this could take up a bit of time but I wont be able to thank you enough for the help.

Colin

[GrahameA]

Morning

IMHO

Some of the best advice you will ever get.

If you are only building one or two bows have you considered purchasing the Bingham kits, it could save you time, money and frustration the first time round.

I do wish to make several bows ...

Even if you want to make a number of bows - starting scratch, assumes you have a design - I would recommend you build a kit from Binghams or from John Clark and if you go with John Clark then spend extra dollars and buy his book on building Longbows.

[Stickbow Hunter]

Colin,

I too think it best if you went with Binghams for your first attempt. If you are going to get your glass from them why not get the lams etc from them as well. They have plans for forms and how to DVD's and can supply kits so you will at least get your bow somewhere near the weight you would like. The lams would come already accurately ground and that is something you won't get if you have your lams cut by Lazaridies. Binghams will already have the glass to lam thickness and taper already worked out to suit their bow design - a very big plus.

In relation to having parallel or tapered lams.; this isn't a matter of what a person likes but rather what the bow design dictates so as you end up with a bow with good shooting qualities. For example if I used parallel lams in my longbows which have the limbs reflexed in the unstrung position the limbs wouldn't be able to bend in the manner they are supposed to. On the other extreme if I put too much taper in the lams the tips would bend too much and become whip ended. The Bowyer has to work out by trail and error what limb taper (or none) works best for his bow design.

For my longbows I use .050" (not .0005" as you incorrectly typed your post above ) glass for bows of 50# and above but recurves usually have thinner glass.

All the best with getting it all sorted and please do keep us up to date with your progress.

It might be a good idea to put your location in your profile so we know where you live as one of us might live nearby and be able to meet up and talk bows.

Jeff

[greybeard]

Colin,

My first and second attempts at making recurved bows employed a one piece form, pressure strips and numerous clamps. The limb profile was based on the early 70s’ Black Widow.
These bows were glued up in two stages because of the relatively short pot life of Techniglue. As a side benefit I was able to feather the fadeouts into the back core lamination.

First Recurve On Form.jpg (92.28 KiB) Viewed 5125 times

You will notice that two quite different looking bows came off the one form.

Recurves.jpg (121.72 KiB) Viewed 5125 times

A two piece form for recurve bows using an air hose and heat strips.

Heat Strip Curing.JPG (67.34 KiB) Viewed 5125 times

With regards to tapered verses parallel laminations this will be dictated by the bow design.

Because of the stiffened tips used in the following bows the actual working limb length is relatively short and a tapered core did not appear to offer any noticeable advantages.

I do not know if you have viewed the following posts.

Recurve #3 [parallel core]

http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=11963

Recurve #4 [tapered core]

http://www.ozbow.net/phpBB3/viewtopic.p ... 5&start=16 [ascending order when logged on]

Hope the above is helpful,

Daryl.

[bigbob]

Plenty of food for thought in those links that Daryl has supplied, Colin. i also agree that the binghams kit would be the best way to begin your quest. I happen to have several blue prints for their recurve bows that to date I've done nothing with.

[hunterguy1991]

Cheers for all the info guys, as I said, very much appreciated!!

You have all pushed the idea of building a kit bow first up (definitely a wise idea!! )and I have looked over the Bingham's kits and liked what I looked at, however I'd like to make an analogy first.

Building a kit bow from pre made parts has its pros and cons, Pro's being its would more straight forward and would result in desired specs and a working bow, BUT it would be a little like building Ikea furniture rather than cabinet making from scratch in that everything is already done for me, its just glue it all together and shape it a bit...

I see making Laminations and forms etc as a big learning opportunity that I would miss in a kit bow. Its a bit of a double edge sword...

Now I hope that you all don't get the wrong idea by this. Several quotes come to mind as Im writing this post...

"You have to crawl before you can walk"
"bull at a gate"
"we only learn from our failures"

I will definitely read through Daryl's posts meticulously and get all the info I can from them. Bob, perhaps we can have a chin wag while im up watching the longbow layup and you can help get me more on the right track.

Jeff, I realised id messed up the glass thicknesses the second I pressed submit... lol oh well, you knew what I meant so for a 50lb recurve would 0.040 glass be sufficient? I live near Woodford in Queensland (between Brisbane and the sunshine coast) but I'll definitely update my profile as well.

I will definitely be making more than a couple of bows (there's nearly endless combinations of timbers one can use in risers and limbs) so I think learning how to make forms and lams will definitely be a good idea.

Straight shooting,

Colin

[Alex]

Donald Assenheimer makes recurves using 3 parallel core laminations and 0.040 glass only.
No taper at all.
Great bows.

Daryl : nice recurves , again.

Alex.

[Stickbow Hunter]

Jeff, I realised id messed up the glass thicknesses the second I pressed submit... lol oh well, you knew what I meant

There is an edit button mate.

so for a 50lb recurve would 0.040 glass be sufficient?

I think that would be about right.

In relation to lams; the Bamboo flooring would be a good alternative IMO.

I don't make recurves but if you ever get up this way give a holler and we can catch up for a yarn.

Jeff

[hunterguy1991]

Cheers Jeff,

Will hopefully be up that way for a fishing trip after Christmas so will definitely look you up while Im up that way.

[little arrows]

I think you might find that even the now well known bowyers (not all mind) have started with a Bingham kit just to get the feel of how it all works, and then applied their own changed/touches from there.

You did forget one saying - no point re-inventing the wheel....

Enjoy the learning.

cheers
sue

[hunterguy1991]

What width of glass/Lams do you most commonly use for recurve bows?

I noticed on Binghams there are 2 different widths of the glass of a given thickness? I had first assumed 2" for recurves and the thinner for Longbows, is that correct? Or can recurves be built using the thinner materials also?

[Stickbow Hunter]

They actually have three widths - 1.5", 1.75" & 2". I would go with the 2" as this will give you a little more room for error. Also I would suggest that you use the ULS Bo-Tuff E-Glass and not the UL Bo-Tuff E Glass as the former has a scrim in it.

Jeff

[greybeard]

Building a kit bow from pre made parts has its pros and cons, Pro's being its would more straight forward and would result in desired specs and a working bow, BUT it would be a little like building Ikea furniture rather than cabinet making from scratch in that everything is already done for me, its just glue it all together and shape it a bit...Colin

Colin, you may be misjudging the kit bow, the only pre shaped components are the core laminations, the riser kit comes as individual pieces and the dymonwood and action wood come in slabs so you still have to do the pre shaping.
You don't have to get the riser material from Bingham's.

Riser Kit.jpg (20.44 KiB) Viewed 5093 times

I see making Laminations and forms etc as a big learning opportunity that I would miss in a kit bow. Its a bit of a double edge sword...Colin

You will need to build a lamination grinder as you cannot use the laminations straight off the saw. You will still have to make your forms from the full sized plans or to your own design.

I use 1 3/4" wide glass for my recurves but the glue up must be precise as there is no room for sideways slippage.

Daryl.

[hunterguy1991]

Jeff, I only came across 2 widths in my search on Binghams site, but if you say there's 3 then I guess there is

Whats the difference between the ULS and UL Bo-Tuff E glass? and what do you mean by "scrim"?

Daryl, what would be the minimum tools required to build one of the Kit bows? I assume a bandsaw and sander of some description (spindle or belt probly best) would help immensely, especially in shaping the riser and limbs after glue up?

I had thought of the sideways slippage issue already and noticed on your previous post in a picture of your form that you have small blocks bolted on to the form to hold the laminations in line. There appears to be 6 pairs (one in close to the riser and 2 out wide near the tips on each end of the bow). I had envisioned something very similar to hold the pieces in line.

Id like to base my design (one of at least) off the old Hoyt I wanted to have remade. I can take measurements to get dimensions and plot the limb curves and fades etc without too much trouble.

Colin

[bigbob]

Scrim is the term applied to unidirectional fibres that are incorporated in the production of the glass. UL has the fibres laying in one direction only while ULS has multdirectional laying. Makes a stronger glass and with the wider sections in recurves is a greatly desirable attribute to help counteract twisting forces for one.Re the side bars or washers on the form to prevent slippage that' s a necessity as 'taming' glued lams is a little like trying to clamp an oiled eel to a sheet of glass.Don't ask me how I know! My most important tools I have are without doubt my band saw by a long way, Lam grinder [home made] and then equally a disc or face sander , and a spindle sander.The spindle sander can be substituted for, with a drum sander attachment that attaches to a good pedestal drill. This is adequate but not as good as the spindle sander. Also as Daryl says you can just order the lams and glass from Binghams and source your own timber for the riser.Whether .040 glass is suitable for your proposed bow is relative to the required draw weight. Different draw weights require a certain stack, ie total core material and glass measured at thickest point. there is a rule of thumb ratio that works fairly well IMO when applying the 'recipe'.

[Stickbow Hunter]

Jeff, I only came across 2 widths in my search on Binghams site, but if you say there's 3 then I guess there is

Read the info in this link on Bingham's site and it clearly offers three widths of glass. http://www.binghamprojects.com/proddetail.php?prod=ULS

hats the difference between the ULS and UL Bo-Tuff E glass? and what do you mean by "scrim"?

Info on the different glass in this link on Bingham's site http://www.binghamprojects.com/products.php?cat=9

Jeff

[greybeard]

A bandsaw is necessary to efficiently shape the riser blank. You will also need some sort of sanding device to remove the saw marks from the blank and to feather the fadeouts.

Recurve Handle Shaped Blank.jpg (57.4 KiB) Viewed 5066 times

All faces need to be at 90˚to each other. The fadeouts can be given a final touch up by hand if required.

The bandsaw will also be useful to cut the bow form to shape.

The complexity of the riser shape will dictate what sanding implements are needed.

Riser 2.JPG (31.69 KiB) Viewed 5066 times

Drum/spindle sanders can be an advantage however sandpaper taped to an off cut of broom handle can be efficient.
The rubber wheel end of my lamination grinder is excellent for concave curves and I like my Black & Decker power file to remove excess wood quickly.

As you work on the bow you will soon become aware of what tools will make the job easier. Above all don’t buy cheap sandpaper, apart from clogging up it dulls very quickly.

Daryl.

[hunterguy1991]

Well, it looks like a Bandsaw is going on the Christmas list for Santa... there are some available at Carbatec for $410, running a 1/2 hp motor.

http://www.carbatec.com.au/carba-tec-10-bandsaw_c19215

Would something like this do the job?

I have a small hand held belt sander at the moment that Ive used for rough wood removal but prefer a decent set of files for finer work. Is it ok to use files on the glass or should I stick to sanders? I imagine they would be a bit hard on the glass.

Daryl, I love the profile of that bow in your last post!! and the timber is beautiful. Very elegant!!

Thanks for the explanation of "scrim" Bob, makes sense now. And very much enjoyed your description of trying to tame the glued glass and lams

More to think about.

Straight shooting.
Colin

[bigbob]

Regards the bandsaw, Carbotec is a reputable company and generally stock good to high quality equipment. The one thing to dwell a little on is to try and buy the best equipment that your budget allows. The bandsaw you mention will cut out risers and such but will be limited in both capacity and 'finesse'. I have a relatively cheap 14'' riser Taiwanese 'knockoff' of a reputable brand and have invested in Quality guide rollers and a good fence, both items of which are highly desirable.It certainly does the job, but if the good fairy ever blessed me with an over abundance of the folding stuff, then I would race out and buy a 17'' industrial quality band saw.This allows ease of reducing log sections and the like. We don't always use ready cut wood for our bows and can be the greatest scroungers around.

[greybeard]

Colin, I agree with Bigbob in the fact that the 10” saw will lack in its cutting capacity.

It may handle the cross cutting and a little ripping but when it comes to ripping down 50 mm thick planks of rock maple for laminations you will be sadly disappointed.

The biggest blade the machine can run is 6.35mm x 6 t p i, which I believe is grossly inadequate for ripping down large planks.

The blades for smaller machines are usually made from a lighter gauge steel and can have a tendency to follow the grain when rip cutting.

Also they don’t make mention of the blade speed. If the blade speed is too slow the cut can choke with saw dust which will mean feeding the timber in at a snails pace.

The wheels on the 10” machine are cast alloy and do not build up the momentum in the same manner that the cast iron wheels do on bigger machines. In essence with cast iron wheels it is like having two flywheels on the machine.

I did own a 10” look a like to compliment my 12” and 14” saws and I was not happy with its performance.

Once you have a band saw you will be amazed at how much use it will get in general wood working projects.

If you can stretch your budget the BAS 350B is a much better choice in my opinion, I was lucky that when I was looking at upgrading my bandsaw Carbatec had them on special for a little over $500.00.

From the Carbatec catalogue; "The best choice when you only need a small bandsaw. Perfect for cutting small pen blanks or for model making."

Daryl.

[Goatchaser]

you can never have too many tools , hope my missus didn't hear that.

[hunterguy1991]

Gday guys,

Daryl, thanks for your honest opinion. I had looked at that particular bandsaw you suggest but they are currently nearly $800 to purchase. I may be able to stretch the budget that far if an engineering job I applied for pulls through.

Im inexperienced with what to look for with regards to machines for wood working as I've had little opportunity to use them. Normally id be stuck with hand tools and have to make do.

Will continue looking around and do some more research on it all.

[greybeard]

Is it ok to use files on the glass or should I stick to sanders? I imagine they would be a bit hard on the glass.

I use a Nicholson Magicut flat file when I want to define an edge or if I want to facet the tip overlays. With files and sanding sticks I always file from the glass to the core to avoid lifting slivers of glass.

Daryl, I love the profile of that bow in your last post!! and the timber is beautiful. Very elegant!!

The riser was cut from a black wattle stump that was in the firewood heap down at the club.

If you have to work within a budget it may be worth checking out the following.

http://www.machineryhouse.com.au/W4202

It is the same size/specifications as my 12" bandsaw.

With the correct blade and speed I could process 50 mm hardwood planks without too much trouble. The secret was to adjust your pushing speed to suit the particular timber and have a sharp blade.

Although their specification sheet mentions bearings in the upper blade guide the one in the illustration appears to have non bearing adjustable guides. Blades with 3 teeth per inch [t p i] seem to suit ripping cuts.

Although this may not be the ideal solution it may be an option.

As a side issue are there any wood working/cabinet makers/shop fitters in your area that could rip down the planks for you for a moderate fee and you could look at directing funds to a lamination grinder.

If you have access to a table saw this will do the job, you just lose more timber because of the thicker blade.

Daryl.

[hunterguy1991]

Thanks for the heads up on that saw Daryl!!

Will definitely keep it in mind. I will suss out whether it does in fact have the bearing blade guides or not and go from there.

I could potentially even push up to this next model as its about between the one you suggested and the next model up from carbatec as far as price goes.
http://www.machineryhouse.com.au/W855

I'm using Nicholson files as well. I tend to file from the edge in towards the middle of the riser just out of habit from woodworking classes in high school so if I'm careful I should be fine with glass as you say.

As for getting timber ripped down, I cant say I know of any places close to home, but I have asked the guys at Lazarides (where I'd be getting most of my timbers, especially limb timbers) if they can rip it down. They mention on their site that they can dress timber for projects from house building to hobby projects, hopefully they can do thin laminations for me.

Colin

[greybeard]

I could potentially even push up to this next model as its about between the one you suggested and the next model up from carbatec as far as price goes.
http://www.machineryhouse.com.au/W855

Colin, it is still basically a 12" saw and if you check the specifications it offers very little for the extra money. The 14" Carbatec is only an extra $21.00

Bandsaw Comparison.jpg (65.84 KiB) Viewed 4981 times

Daryl.

[greybeard]

Colin, when you are ready to grind your own laminations this is the grinder/belt combination some bowyers use. I have mine mounted vertically through the bench.

Abbott & Ashby 8 inch Grinder And Multitool.jpg (115 KiB) Viewed 4966 times

http://www.machineryhouse.com.au/L085

There are alternatives depending on what type of drum/belt tools you already have in the workshop.

Daryl.

[hunterguy1991]

Thanks heaps for that link Daryl!! I really do appreciate the time you have put in commenting on my work and making suggestions for tools to use.

That might be able to be a birthday present early next year and the last piece of the puzzle to get me started.

You say that you have you grinder/linisher mounter vertically through your bench. To grind a taper I imagine you would have it mounted on the thin edge against something square and then pass it perpendicular to the belt to grind the timber off? Or is this incorrect? Can you explain the process of grinding a taper as I've been wondering about the method for a while now.

I also have some questions about the way to construct different types of forms for bows.