Discuss replacing steel cables for fastflight at the Compound Bow within Archery Interchange UK Forums; hello!
I have an older bow (mid 90's) which I've recently replaced string (the wire ...
18-05-11 05:26 PM # ADS
Tread very carefully before trying to change steel to fastflight.
I was going to try it on a 1990 Firecat but the dealer warned me off.
Steel believe it or not is a lot less punishing on limbs and riser than Fastflight.
Limbs that are not designed for Fastflight could fail with terrible results.
The stresses involved in a compound bow are considerable and if components are not up to the job you could be in real trouble.
hm.. what about putting more strands (22/24?)? Or the use of dacron? Don't like dacron though as I heard it keeps creeping... Then again, the steel wire hasn't been replaced since the making of the bow (1995- ish). Plastic wrapping around them looks okay thou.
I guess the chances are bigger that the 16 year old steel wire is going to break than the limbs/riser due to modern materials. Any thoughts?
Note: bow does not have any tear drop.
Compounds have to be "timed" so the cams stay in sync.
Dacron stretches like knicker elastic so your timing would drift out as would your peep.
Compound strings/cables are usually made under load to minimize stretch unlike a recurve string.
As I said earlier these "early" bows were constructed for steel cables.
I think Golden Eagle still make bows so why not e mail them to see if its a viable proposition.
Please take care as an exploding compound can really spoil your day !!
Changing cams can seriously change the draw weight and draw length of the bow.I have changed steel for fastflight before,but I used the same cams.
I have changed cams before, too, but was not happy with the weight or draw length afterwards. Cams that are different shapes can have very different effects when fitted.
It is possible to get the right information from a manufacturer sometimes, especially if you are changing their cams for others of theirs that were designed for your bow.
From your picture it looks like the new cams would never have been designed for your bow; they may be from a different make of bow, so no one would have the charts to work from.
In the past, I would have wanted to do what you want to do. Looking at your situation from where I am now, I think there are too many things that are unlikely to match, to make it worthwhile.You might make several strings and cables before they were the right lengths. You might find after all the work, the weight is far too high or far too low; or the draw length was too long/short.
I would go for changing the steel cables for fastflight ones, using the same cams.Fit the little plastic pulley that you see on the axle on the last photo, inside the limb fork of your bow. Fit the loop of the cable round that pulley before sliding the axle through.The other end of the steel cable has a metal blob on the end I think, That fits into a round cut away in the cam, if I remember correctly.That is difficult to duplicate for a fastflight string.I think my cams had a spare peg for the bow string, so I drilled through the cam from the cable side to the string side and used the spare peg to attach the cable; having made a loop at that end to fit over.I had to round over all the corners that the cable would pass over so nothing could cut the string material.I made the cables a bit longer as the end had further to reach to get to the pegs.
I would get it de-strung and left that way (left in a loft long enough it will explode usually the bow bag stops it going everywhere) - not worth the bother, trip to casualty or worse for the sake of a few quid.
I am sometimes worried at the lack of maintenance on newer bows so I am certainly not happy shooting along side somebody with a bodged bow under high tension.
Why de-string it if its still capable of shooting.. There are no obvious signs that its going to fail any soon. People are shooting with bows much older than 16 years, without any problem. The only thing I'm concerned about are the steel cables, as it is impossible for me to see what has happened insode of the nylon coating after 16 years of use. Maybe hair cracks in the old magnesium-aluminum riser and limbs that might grow as time passes are a hazard too but my daily life consists of actions which are much more likely to injury than shooting this bow (going to school, walking stairs, crossing a road, etc). I agree and respect though that bystanders should not be put at risk by what is in your, and plenty other peoples, eyes doubtful decision making. So feel free to take a few steps aside . (just joking.. I'm not shooting this at busy events, such as FITA's (70lbs is above the 60lbs limit). Field and 3D at most, mainly 3D on a private range though).
I'm very glad someone that has previous knowledge about this has seen my topic, thanks!
I dont want to replace the cams. I like them the way they are. Draw length and weight are both spot on. I was wondering if someone could tell me what type of cams these are, and what cam system is used? They certainly are not soft.. As the cams are made of black plastic, I think metal fatigue is no issue here.
The metal cable is attached on one side to the limb fork by the grey metal pulley. A little plastic pulley is used on the modern bow at the last photo. I was wondering where I am able to purchase these? I have a measuring instrument (caliper) lying somewhere, I can measure the dimension to some accuracy.
I also don't have a spare peg lying around anywhere.. Is it possible to get these somewhere aswel? Perhaps re-use it somehow from the steel wiring?
A bowpress is available only in the weekends (at the archery range), so I'll then try to find out some more.
How's your fixed bow holding out by the way?
The cams look like some I saw on a Barnett bow. they are wide and plastic and round.By soft we don't mean to touch, but soft to draw. The draw slowly feels heavier and then slowly feels lighter.At the end they are spongy so you can pull a bit more and they get slightly heavier again.A gentle sort of draw.Your bow is described as twin cam as the two are mirror images of each other.
Hard cams draw very differently. They are very stiff at the start, they stay stiff for most of the draw and suddenly get light at the end. They then stop and won't pull any further.
If you look at the string that you pull, you should be able to follow each end to where they fix to the cam. I had a feeling that the string has a loop on both ends and the loop fits over a post or peg. I had an idea that there might be two of these on each cam so you can loop the string over one or the other to change draw length. Perhaps I am wrong. You may have one peg or post with different slots to allow the string to take different routes into the peg from the outside groove. They also adjust draw length.
The little plastic pulleys you might get from an archery shop, if not I have some or can make them.
The steel cable has the metal loop on one end that fits over the axle. The other end of the cable had a round blob fixed onto it,yes? That blob fits into a hole that allows it to hold the end of the cable into the cam. Like the end of a bike brake cable, yes? If you imagine a loop on the end of the new fastflight bow string; it could be wrapped round the blob, cut from the end of the steel cable, but then it would not fit back into the hole. The blob would need a groove cutting round it for the cable to fit in when wrapped round.Might be easier to make a grooved pulley idea to fit the hole.So long as the string material can't get crushed against any edges.
My conversion worked well enough, but that was 20 years ago. The riser is still in the garage and the limbs. It was my first compound, but I've had a few since then. It was very gentle to shoot and quiet.
I think I need to add that compounds are dangerous and can go wrong when being assembled or disassembled. The limbs are under a lot of tension even before they are drawn. If a string breaks in use, it can be very dangerous for anyone close by.I was lucky when a string broke on one of mine!!! Getting strings crushed or caught on slightly sharp edges is something to be on your guard against. It is always difficult to know what any person is capable of when the only contact is over the net. Many archers will have nothing to do with their compounds. Some will try anything and have no ideas of the consequences. You might be totally at home working with one. It is better for me to try to explain the dangers, as others have done; rather than leave things unsaid just in case you already know.
Thanks for the tips! Really appreciate it. The bow is disassembled at the moment, as I discovered there is a small dent (1/10th of the cable) where the nylon is gone and some steel (I think only 1 or 2 or the 30 broken). What puzzles me the most is that the shop that made the new string for me (not cables) didnt tell me anything about that :/.. Better safe than sorry I guess!
I also managed to know some more about how the string and cables are attached to the cam. Here is some 3d animation I made:
Youtube : Current Status
1. The 'wire' with the loop is the fast flight string (currently attached)
2. Blob is weld/made to the metal cable
3. Big round thing is the cam
This is how I would fix it:
Youtube : Suggested fix?
Wondering how to make this :S I have no workbench or any ironworking equipment...
Also the attachment on the axle is still troublesome..
I like the animation; wish I could do that sort of stuff.
What you want to make is a blob that has a groove on both sides so the fastflight can be attached to each end, yes? You will need two, one for each cam/cable.
2. Blob is weld/made to the metal cable
All I need to make those, is the total length and diameter.Also the distance in from the ends for the two grooves. Have you managed to get some plastic pulley shapes to fit the cable loops to the axles?
The broken line represents the path of the current steel cable as it exits the hole for the blob.
The cut away bits in the lower pic will need to be deeper on that side of the trench to allow a nice radius for the curve put into the loop as it bends on its way out.
If you wrap some string round a pencil to represent a loop wrapped round a blob, and try to fit it into the hole while the bow is disassembled ,you will see where plastic contacts the string and how it needs to be cut away and rounded. A dremel might be useful.
Why de-string it? because unless it has been overhauled by some one who knows what they are doing it is dangerous. I own and shoot a compound bow made in 1986 but it has been completely stripped and serviced with new manufactures parts, it is therefore as the maker designed it.
You on the otherhand are modifying a bow out of makers specs without stripping and checking the condition with materials that will increase the stress on the bow. It's not a case of 'if' but when it breaks.
just point,pull & squeeze the trigger
if it's old enough to have steel cables then I can't imagine why you would want to shoot it. it's a relic, treat it as such.
Fine fine.. It are just minor modifications, and I reckon that it will be safer to shoot with the mods as I don't have to worry about any steel cables that might snap.
I've found someone that can CNC these parts for me: YouTube - ‪twee‬‏. Again, ruling out the failure of the 2 decades old steel cables.
The cams will remain unchanged; no drilling or structural weakening in any part of the bow.
I wonder though how steel compares to modern fibers? Isn't it less forgiving as it has basically no creep or stretch? Its heavy, but still...
Also, quoting on Jerry Tee's argument of the increase of stress induced by modern materials; pro bow shop recommended me fastflight, as there was already fastflight on the bow when I bought it (not new), but I'm pretty sure that this is not the original string. I'm willing to use dacron for both the cables and string, as stated above, wouldn't this be more forgiving for the bow as dacron stretches more than steel? I can make my own strings, so the creep isn't a problem I guess if I change strings every (half a) year (dacron is cheap).
exactly as you described it .
Here are some more detailed pictures of the cam:
Blob half in cam:
Blob in cam (steel cable side):
Blob in cam (other side: for string):
Images of the bow (posted before somewhere else):
I'm a student, so not much money for brand new hoyt shiny bow , wish I could afford..
I wasn't quite right with my sketches. It seems the new string will attach to the new blob further into the centre of the cam than I had shown. That is better .so the string will loop round and be single thickness before exiting the groove onto the profile of the cam.That is better! I hope you are sorted soon and can enjoy your shooting.
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