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View Full Version : Shortening a K90?


corners
08-28-2009, 06:24 PM
The K90 has a hard plastic piece at the end of the pallet, under the buttcap. The plastic piece seems to serve as the base or platform for the buttcap, and doubles as a buttweight.

If you've ever removed the grip on a K90 you may have noticed that you can also see four black plastic tabs peeking through the pallet foam just above the buttcap. I think these tabs are part of this plastic piece. The plastic piece appears to be a 'sub-buttcap' that is attached to the raw graphite handle. Then Wilson lays the foam of the pallet over everything.

In the past, manufacturers have stuck lead weights between the two graphite shafts that make up the handle - a butt weight. I think Wilson decided they may as well make a butt weight that has some structural purpose - this plastic piece. Maybe this has something to do with the braided construction of the K90 - the braided graphite/kevlar fabric might not be that robust at its 'end'.

So, I'm wondering if anyone has cut a K90, or other Wilson racquet that also has this hard plastic 'sub-buttcap'.

Anyone?

Any practical info on this (weird and foolish) subject would be appreciated. Opinions are also welcome, but please refrain from comments such as: "It's stupid to cut a K90; what, are you a midget?", etc.

corners
11-19-2009, 01:20 PM
OK, for crazies:

I cut 1/2" off an Asian K90. The plastic butt assembly sawed pretty easily. Cutting off 1/2" amounted to about 2/3 of the plastic assembly.

I'm still concerned about the robustness of the end of the handle sans plastic assembly, as I assume it was there primarily to strengthen the end of the pallet, and secondarily to function as a butt weight. But I think and hope what's left of the assembly will still function to strengthen the junction of pallet and butt cap.

Interestingly, exactly .1 mm beyond the 1/2" point there is a metal bar that spans the inside of the handle cavity from bevel 3 to bevel 7. The bar passes through the graphite and foam of the handle and the ends are flush with the pallet surface on those bevels. I don't know if this is reinforcement, butt weighting, or what, but it was conveniently located just beyond where I cut the handle.

New butt cap installed nicely after I sanded down the pallet 1 grip size, using the new smaller butt cap to guide the dimensions. BTW, I'd avoided reducing the grip size for a long time, fearing a screw up, but using a sanding block, 100 grit paper, bench clamp and a vernier caliper I found it rather easy to reduce the grip.

I've hit a little bit with the frame, but haven't leaded it back up to where it came from (removing 1/2" reduced swingweight by ~ 20 units). I'm a bit concerned about the strength of the end of the handle due to mauling the plastic assembly, but time will tell if this mod is a success or a disaster. Anyway it's an experiment, so we'll see.

travlerajm
11-20-2009, 04:13 PM
OK, for crazies:

I cut 1/2" off an Asian K90. The plastic butt assembly sawed pretty easily. Cutting off 1/2" amounted to about 2/3 of the plastic assembly.

I'm still concerned about the robustness of the end of the handle sans plastic assembly, as I assume it was there primarily to strengthen the end of the pallet, and secondarily to function as a butt weight. But I think and hope what's left of the assembly will still function to strengthen the junction of pallet and butt cap.

Interestingly, exactly .1 mm beyond the 1/2" point there is a metal bar that spans the inside of the handle cavity from bevel 3 to bevel 7. The bar passes through the graphite and foam of the handle and the ends are flush with the pallet surface on those bevels. I don't know if this is reinforcement, butt weighting, or what, but it was conveniently located just beyond where I cut the handle.

New butt cap installed nicely after I sanded down the pallet 1 grip size, using the new smaller butt cap to guide the dimensions. BTW, I'd avoided reducing the grip size for a long time, fearing a screw up, but using a sanding block, 100 grit paper, bench clamp and a vernier caliper I found it rather easy to reduce the grip.

I've hit a little bit with the frame, but haven't leaded it back up to where it came from (removing 1/2" reduced swingweight by ~ 20 units). I'm a bit concerned about the strength of the end of the handle due to mauling the plastic assembly, but time will tell if this mod is a success or a disaster. Anyway it's an experiment, so we'll see.

I look forward to hearing how this goes. My 26.5" diablo gives me more control than any frame I've ever used - I imagine the K90 is similar.

I find that I can manage a higher static weight on these shortened frames while still maintaining maneuverability. The key is adjusting the balance just right, and not being satisfied until you have the right balance.

I usually add mass at the 2 and 10 positions until I get to my preferred SW. Then I add mass a little at a time near the top of the handle to make the tip come around faster until it feels right.

corners
11-20-2009, 05:16 PM
I look forward to hearing how this goes. My 26.5" diablo gives me more control than any frame I've ever used - I imagine the K90 is similar.

I find that I can manage a higher static weight on these shortened frames while still maintaining maneuverability. The key is adjusting the balance just right, and not being satisfied until you have the right balance.

I usually add mass at the 2 and 10 positions until I get to my preferred SW. Then I add mass a little at a time near the top of the handle to make the tip come around faster until it feels right.

Hey, thanks for the tip. Do you leave as is, add at 10 and 2 to get your preferred swingweight and then go from there at 7"? Or do you make an effort first to buttweight to get near the original balance point of the frame, then dob at 7"?

BTW, it occured to me that I could reinforce the butt, where the plastic assembly was, by pouring thin (1/8") layers of epoxy an inch deep inside the handle, one at a time, per quadrant.

Also, since all the silicone blacked-out Staffs started being played, it occured to me that I could also pour a silicone piece to replace the butt weight, serving as further reinforcement. The half inch chunk of assembly I removed weighed about 16 grams, so I thought I'd replace that weight first - may as well do it with silicone. Any thoughts on that idea (from a structural or weight-distribution POVs)?

quest01
11-20-2009, 06:03 PM
I cut a few APDC's in the past and had no problems. They were both extended length racquets so I just used a tape measure to measure a .5 inch less and marked it with a pen. Afterwards I took my chainsaw out and cut half inch off the handle.

corners
11-20-2009, 06:30 PM
I cut a few APDC's in the past and had no problems. They were both extended length racquets so I just used a tape measure to measure a .5 inch less and marked it with a pen. Afterwards I took my chainsaw out and cut half inch off the handle.

Chainsaw?!

Steve Huff
11-20-2009, 08:18 PM
There's really nothing wrong with a 26.5" racket. Many of the old Fischer and Snauwaert "control" frames were actually shorter than 27". Like you, they found that a heavy racket was more stable and by shortening it, they could keep the swingweight low enough to maintain manueverability.

travlerajm
11-20-2009, 08:54 PM
Hey, thanks for the tip. Do you leave as is, add at 10 and 2 to get your preferred swingweight and then go from there at 7"? Or do you make an effort first to buttweight to get near the original balance point of the frame, then dob at 7"?

BTW, it occured to me that I could reinforce the butt, where the plastic assembly was, by pouring thin (1/8") layers of epoxy an inch deep inside the handle, one at a time, per quadrant.

Also, since all the silicone blacked-out Staffs started being played, it occured to me that I could also pour a silicone piece to replace the butt weight, serving as further reinforcement. The half inch chunk of assembly I removed weighed about 16 grams, so I thought I'd replace that weight first - may as well do it with silicone. Any thoughts on that idea (from a structural or weight-distribution POVs)?

Adding weight at 6 or 7 inches from the butt is the most efficient way to speed of the angular velocity on your groundstrokes. Adding additional weight in the butt will result in a frame that is higher static weight, but it will feel more maneuverable at net.

quest01
11-21-2009, 02:06 PM
Chainsaw?!

Thats correct I used a chainsaw to cut a .5 inch off the handle to make it a standard length racquet. I only had two options, use a saw or a chainsaw and I chose the chainsaw because it would be faster. I just whipped out my chainsaw and cut the section off quickly and painlessly.

jazzyfunkybluesy
11-21-2009, 04:01 PM
This would make the racquet more head heavy. You could do the same thing by adding lead at 12 oclock.

quest01
11-24-2009, 08:27 PM
Chainsaw?!

I actually have a fascination with chainsaws, I've always loved the roar of a chainsaw. Anything that I don't need I cut in half with my chainsaw, that could be old furniture, my old car, old computers, old tv's, etc... Basically anything I don't need anymore I cut in half with my chainsaw and the reason why I chose a chainsaw over a saw to cut the handle off my racquets is due to the fact that a chainsaw is much more proficient compared to a standard saw.

Soundog
11-25-2009, 03:42 AM
Quest, do you live in Texas ???:shock::twisted:

corners
11-25-2009, 05:43 AM
This would make the racquet more head heavy. You could do the same thing by adding lead at 12 oclock.

Generally cutting off from the handle end does not result in a more head heavy frame. Yes, you are removing weight from the handle end so you'd think it would result in balance shifting toward the head, but you are also moving the 'center' of the racquet by shortening it. So unless the piece you remove from the butt is dispropotionately heavy (like it has a chunk of lead in it), shortening a racquet actually results in moving the balance down (more HL) slightly.

quest01
11-25-2009, 10:50 AM
Quest, do you live in Texas ???:shock::twisted:

No I don't, why

Soundog
11-26-2009, 03:04 PM
I'm just being silly. ( Probably ) before you were born, there was a classic movie called the Texas Chainsaw Massacre (1974). I was wondering what it is about Texans and chainsaws....

Anyway, back on topic :

I noticed the steel pin in the butt of my K90's when I lengthened them. My guess is that they are there for weight rather than strength and personally, I wouldn't worry about them too much.

I've got an old Kennex which had a sizeable lead chunk in the handle for counterweight purposes and which also seemed to provide a measure of strengthening to the butt of the handle. when I took it out to lengthen it, the handle end felt very flimsy, but after putting the plug in and the butt cap back on, everything felt normal again and it hasn't broken so far.

corners
01-06-2010, 12:31 AM
Preliminary report on AK90 cut to 26.5":

After cutting, the frame had a swingweight of less than 300. I added 6 grams of lead to the upper hoop (from 10 to 12 to 2) and 3 additional grams at 10 & 2 (so I now have two layers at those positions). This has returned the frame to it's original swingweight.

Cutting 1/2" off the handle reduced the butt weighting by quite a lot, as the K90 and AK90 have a plastic assembly at the end of the pallet that I had to partially remove (by cutting it in half). Consequently, I added about 10 grams under the trap door (fishing weights) to re-balance the frame. The fishing weights are easily removalbe - I want to keep everything removable for now.

I also attached 10 grams worth of fishing weights to one of those rubber bands used to secure the grip. I'm using this to experiment with the "MgR/I tuning method" described by Travlerajm. With this I can move the band up and down the grip, changing the balance of the frame (and thus, MgR/I).

(I'm convinced Travlerajm is onto something with his MgR/I "double pendulum" theory - mainly because I'm also playing with a couple of wood frames and find that, despite their heavy weight (~380 grams) and high swinweights (350+) they come around surprisingly fast.

I'd always thought headlight frames swung easier, at a given swingweight, than less headlight ones. But last year I started playing with these woodies and noticed that, despite their hefty specs and long balances (close to even balance) they swung surprisingly easy, and on some shots (high dip-drive forehands for example) they were much easier to whip into the ball than the rather wimpy but nimble AK90 (wimpy by comparison). I started to play around with longer balances then, but since reading his recent threads on MgR/I I'm taking an even closer look with my cut AK90.)

Anyway, with my current 9 grams in the hoop my 26.5" AK90 is at 320SW, 32.5cm, 340 grams - about the same specs I had before I made the cut. With 6 grams at 10 & 2 the twistweight is about 13 (USK90 ~ 12.5; AK90 ~ 12). At 320 swingweight and with the center of the hoop now 1/2" closer to my hand, the hittingweight, power potential and plowthrough are about the same or a little better than a K90 with swingweight of 340.

And it plays like it. It is much more stable and quite a bit more powerful than than it was before the cut. At 5' 7" I find the reduced length easier to maneuver, especially on forehand and at the net. All strokes seem improved with this setup, aside from serve, where the jury is still out.

In general, my experience is consistent with what I expected having read Travlerajm's posts about the benefits of cutting. Compared to uncut, the frame is more maneuverable, more powerful and much more stable and solid. And this comes at the loss of only ~ 1mph in racquet head speed at the impact location. (The center of the stringbed on a shorter racquet is closer to the center of rotation (wrist) and therefore is moving slower than it would be in a longer racquet - the opposite of an extended length frame).

And at net it really shines! It's interesting to feel like I have the same stability and plow at the net that I did with a USK90, but in a package that weighs half an ounce less and swings 20 RDC units easier. At this weight and balance the thing feels like I'm blocking the ball back with a big, heavy ping pong paddle.

The benefits of the extra weight in the head that are enabled by reducing length have me looking at leading the sucker up beyond my normal specs. This is also motivated by my experiences with heavy, evenly balanced woodies. Travlerajm claims that a shorter frame allows you to swing more mass. Since I've got a reel of lead I've got nothing to lose.

I'm eyeing ~340grams/~32.5cm/330 swingweight (a swingweight I've found in the past to be too much for match play) and plan to use the leaded rubber band as a tuning device. Perhaps with a tuned balance point 330 swingweight will be OK.

Finally, there doesn't seem to be an issue with the butt end of the frame. Cutting the plastic assembly in half didn't result in a loss of structural integrity in the handle under the butt cap - or not that I've noticed in ~ 15 hours of play.

For those posters who have read Travlerajm's threads about shortening racquets - I suggest giving it a go, maybe with an old mid you have laying around. I think you might be surprised by how nicely it works out.

travlerajm
01-06-2010, 07:51 PM
Preliminary report on AK90 cut to 26.5":

After cutting, the frame had a swingweight of less than 300. I added 6 grams of lead to the upper hoop (from 10 to 12 to 2) and 3 additional grams at 10 & 2 (so I now have two layers at those positions). This has returned the frame to it's original swingweight.

Cutting 1/2" off the handle reduced the butt weighting by quite a lot, as the K90 and AK90 have a plastic assembly at the end of the pallet that I had to partially remove (by cutting it in half). Consequently, I added about 10 grams under the trap door (fishing weights) to re-balance the frame. The fishing weights are easily removalbe - I want to keep everything removable for now.

I also attached 10 grams worth of fishing weights to one of those rubber bands used to secure the grip. I'm using this to experiment with the "MgR/I tuning method" described by Travlerajm. With this I can move the band up and down the grip, changing the balance of the frame (and thus, MgR/I).

(I'm convinced Travlerajm is onto something with his MgR/I "double pendulum" theory - mainly because I'm also playing with a couple of wood frames and find that, despite their heavy weight (~380 grams) and high swinweights (350+) they come around surprisingly fast.

I'd always thought headlight frames swung easier, at a given swingweight, than less headlight ones. But last year I started playing with these woodies and noticed that, despite their hefty specs and long balances (close to even balance) they swung surprisingly easy, and on some shots (high dip-drive forehands for example) they were much easier to whip into the ball than the rather wimpy but nimble AK90 (wimpy by comparison). I started to play around with longer balances then, but since reading his recent threads on MgR/I I'm taking an even closer look with my cut AK90.)

Anyway, with my current 9 grams in the hoop my 26.5" AK90 is at 320SW, 32.5cm, 340 grams - about the same specs I had before I made the cut. With 6 grams at 10 & 2 the twistweight is about 13 (USK90 ~ 12.5; AK90 ~ 12). At 320 swingweight and with the center of the hoop now 1/2" closer to my hand, the hittingweight, power potential and plowthrough are about the same or a little better than a K90 with swingweight of 340.

And it plays like it. It is much more stable and quite a bit more powerful than than it was before the cut. At 5' 7" I find the reduced length easier to maneuver, especially on forehand and at the net. All strokes seem improved with this setup, aside from serve, where the jury is still out.

In general, my experience is consistent with what I expected having read Travlerajm's posts about the benefits of cutting. Compared to uncut, the frame is more maneuverable, more powerful and much more stable and solid. And this comes at the loss of only ~ 1mph in racquet head speed at the impact location. (The center of the stringbed on a shorter racquet is closer to the center of rotation (wrist) and therefore is moving slower than it would be in a longer racquet - the opposite of an extended length frame).

And at net it really shines! It's interesting to feel like I have the same stability and plow at the net that I did with a USK90, but in a package that weighs half an ounce less and swings 20 RDC units easier. At this weight and balance the thing feels like I'm blocking the ball back with a big, heavy ping pong paddle.

The benefits of the extra weight in the head that are enabled by reducing length have me looking at leading the sucker up beyond my normal specs. This is also motivated by my experiences with heavy, evenly balanced woodies. Travlerajm claims that a shorter frame allows you to swing more mass. Since I've got a reel of lead I've got nothing to lose.

I'm eyeing ~340grams/~32.5cm/330 swingweight (a swingweight I've found in the past to be too much for match play) and plan to use the leaded rubber band as a tuning device. Perhaps with a tuned balance point 330 swingweight will be OK.

Finally, there doesn't seem to be an issue with the butt end of the frame. Cutting the plastic assembly in half didn't result in a loss of structural integrity in the handle under the butt cap - or not that I've noticed in ~ 15 hours of play.

For those posters who have read Travlerajm's threads about shortening racquets - I suggest giving it a go, maybe with an old mid you have laying around. I think you might be surprised by how nicely it works out.
The weighted tuning band is a great idea. I usually do the same thing using long strips of lead tape wrapped around the outside of the grip, but your way is quicker to adjust.

corners
01-06-2010, 09:36 PM
The weighted tuning band is a great idea. I usually do the same thing using long strips of lead tape wrapped around the outside of the grip, but your way is quicker to adjust.

Thanks, but the rubber band, I think, was your idea originally. You can, though, quickly add weight by taping fishing weights to the rubber band with a little athletic tape. The whole thing can be moved up and down for fine adjustments. I haven't had time to go-a-tuning yet, but looking forward to it.

You mentioned that you tuned in a racquetball court. What exactly is your process?

Azzurri
01-09-2010, 05:58 AM
I cut a few APDC's in the past and had no problems. They were both extended length racquets so I just used a tape measure to measure a .5 inch less and marked it with a pen. Afterwards I took my chainsaw out and cut half inch off the handle.

LOL...LOL...OH MY GOD!!!! a CHAINSAW????? how full of crap are you?