I have been seeing a lot of people lately with really flat thumbs. It seems everytime the weather and seasons change I get this influx of thumb issues and its to be expected. But I want to know for the general bowler who is really flat, can they come out of a ball easier from a 45* thumb angle? I'm talking about people who are using oval thumbs for the first time.
Here is my oval technique and appreciate any and all corrections and comments.
1. I use digital calipers and measure the widest part of the thumb. example - .937
2. I then measure the flat part of the thumb to get my pilot hole. i.e. .867
3. I would use a 55/64 bit and cut at 45* using right and down for right handers until I achieved 15/16 width or .937
if I move the table 1:1 @ .021 it will .030 at a time. so I would need to make up .078 divide it by .030 = 2.6 cuts @ .011 .032 and .053
So for a first time oval thumb would 45* be appropriate? Of course using proper pitches. First timers have a hard time with ovals for obvious reasons.
But I'm concerned about the wiggle room the skinny thumb necks cause.
4.
To Oval or Not to Oval
Moderator: Moderators
-
- Member
- Posts: 72
- Joined: February 27th, 2010, 11:02 pm
- THS Average: 215
- Positive Axis Point: 3 1/2R 1/8U
- Speed: 15.75 Qubica 17.25 fl
- Rev Rate: 360
- Axis Tilt: 15*
- Axis Rotation: 60
- Preferred Company: Storm/RG
To Oval or Not to Oval
Right handed
PAP: 5 1/2-> x 1 1/8^
Speed: 15.75 Qubica 17.25 @ release
RPMS: 360
Axis Rotation: 70-75*
Axis tilt 13-15* (Video)
High Game 300
High Series 804
PAP: 5 1/2-> x 1 1/8^
Speed: 15.75 Qubica 17.25 @ release
RPMS: 360
Axis Rotation: 70-75*
Axis tilt 13-15* (Video)
High Game 300
High Series 804
Re: To Oval or Not to Oval
Although, most bowlers may fall into the 45 degree oval, some do not. I would suggest you check each bowler for the exact degree of oval they will need. There are various methods for doing this.
As far as drilling the oval, I use a Ovalmatic machine. I feel this is the best out there and doing ovals is extremely easy. Hopefully, some of the other guys that drill ovals like you will post back with any other suggestions that might be helpfull.
As far as drilling the oval, I use a Ovalmatic machine. I feel this is the best out there and doing ovals is extremely easy. Hopefully, some of the other guys that drill ovals like you will post back with any other suggestions that might be helpfull.
Press the + button if you feel I've been helpful
-
- Member
- Posts: 72
- Joined: February 27th, 2010, 11:02 pm
- THS Average: 215
- Positive Axis Point: 3 1/2R 1/8U
- Speed: 15.75 Qubica 17.25 fl
- Rev Rate: 360
- Axis Tilt: 15*
- Axis Rotation: 60
- Preferred Company: Storm/RG
Re: To Oval or Not to Oval
I check the thumb angles and I use a sheet that is trigged out alread and then factor it.
Its the first timers that are the most problematic as they don't come out of the ball the same way everytime and oval requires you to do.
Its the first timers that are the most problematic as they don't come out of the ball the same way everytime and oval requires you to do.
Right handed
PAP: 5 1/2-> x 1 1/8^
Speed: 15.75 Qubica 17.25 @ release
RPMS: 360
Axis Rotation: 70-75*
Axis tilt 13-15* (Video)
High Game 300
High Series 804
PAP: 5 1/2-> x 1 1/8^
Speed: 15.75 Qubica 17.25 @ release
RPMS: 360
Axis Rotation: 70-75*
Axis tilt 13-15* (Video)
High Game 300
High Series 804
-
- Member
- Posts: 80
- Joined: March 6th, 2010, 3:37 am
- THS Average: 215
- Positive Axis Point: 4 5/8 over 3/8 up
- Speed: 16 mph off hand
- Rev Rate: 210
- Axis Tilt: 20
- Axis Rotation: 75
Re: To Oval or Not to Oval
For first time ovals we determine the appropriate "degree" and then measure the thumb with the calipers as you have stated to establish the pilot hole and width of oval. Our shop has a vacu-jig with a digital read-out. We set the pitches and drill the thumb pilot hole (we drill thumb hole first). We then set the digital to .000 for both pitches. Using the WIKI oval thumb chart we set the vertical and horizontal numbers for our required oval. We usually make two cuts for the oval:
A 45 degree oval at .030s for a right hander would be (+).021 vertical (y axis) and (-).021 horizontal (x axis) for one cut and then (-).021 y axis ... (+).021 x axis for second cut. For a left hander our vertical & horizontal values would both be positive for one cut and both be negatiove for the second cut.
For wide ovals (.090 - .120) we use multiple cuts, but in one direction (right hander: (+) x axis; (-) y axis) to "smooth out" the ridges in the hole.
A 45 degree oval at .030s for a right hander would be (+).021 vertical (y axis) and (-).021 horizontal (x axis) for one cut and then (-).021 y axis ... (+).021 x axis for second cut. For a left hander our vertical & horizontal values would both be positive for one cut and both be negatiove for the second cut.
For wide ovals (.090 - .120) we use multiple cuts, but in one direction (right hander: (+) x axis; (-) y axis) to "smooth out" the ridges in the hole.
-
- Member
- Posts: 111
- Joined: January 28th, 2010, 3:15 pm
- Preferred Company: free agent
Re: To Oval or Not to Oval
not to rehash this topic but i was about to post a similar question. i use a 55/64 thumb hole in the winter but need a 7/8 round thumb hole to clear my thumb in the summer. my shop lets me drill my own equipment and i would like to try an oval thumb for a better fit.
how do you determine the angle of the oval that is needed?. also, is .030 the normal amount that i should move the press because i'm not sure if they have calipers anymore.
how do you determine the angle of the oval that is needed?. also, is .030 the normal amount that i should move the press because i'm not sure if they have calipers anymore.
-
- Pro Shop
- Posts: 711
- Joined: December 16th, 2010, 5:05 am
- Heavy Oil Ball: Motiv Cruel or Mutant Cell Pearl
- Medium Oil Ball: Rising Star
- Light Oil Ball: Silver Recon or Frenzy
- Location: WV
Re: To Oval or Not to Oval
You need to put your thumb in the ball, and look at how it lies in the hole.
A quick and dirty on doing it with limited tools:
Draw your center grip line on the ball, draw one perpendicular do this line through the center of your thumb hole. Now you have 0 degrees, and 90 degrees marked on the ball.
Put your hand in the ball, and draw a line on each side of the thumb. Line up a flexible protractor with your 0 and 90 degree lines to see where your oval angle lies in that range.
A quick and dirty on doing it with limited tools:
Draw your center grip line on the ball, draw one perpendicular do this line through the center of your thumb hole. Now you have 0 degrees, and 90 degrees marked on the ball.
Put your hand in the ball, and draw a line on each side of the thumb. Line up a flexible protractor with your 0 and 90 degree lines to see where your oval angle lies in that range.
-
- Member
- Posts: 111
- Joined: January 28th, 2010, 3:15 pm
- Preferred Company: free agent
Re: To Oval or Not to Oval
ok, i understand that part. another question, is it normal for to try to oval the back of the thumb in addition to the x and y axis? i had someone do that without actually measuring the height of my thumb.
-
- Pro Shop
- Posts: 711
- Joined: December 16th, 2010, 5:05 am
- Heavy Oil Ball: Motiv Cruel or Mutant Cell Pearl
- Medium Oil Ball: Rising Star
- Light Oil Ball: Silver Recon or Frenzy
- Location: WV
Re: To Oval or Not to Oval
If you are taking more out of the back of the thumb, then you are changing the pilot hole size.
-
- Member
- Posts: 111
- Joined: January 28th, 2010, 3:15 pm
- Preferred Company: free agent
Re: To Oval or Not to Oval
ok thanks. i'll see how it goes later on this week.
- Nsane
- Certified Coach
- Posts: 650
- Joined: June 15th, 2010, 5:01 pm
- THS Average: 190
- Positive Axis Point: 5 3/16 - 7/8 up
- Speed: 17
- Rev Rate: 300
- Axis Tilt: 13°
- Axis Rotation: 55°
- Heavy Oil Ball: Brunswick Tenacity, Radical Tremendous
- Medium Oil Ball: Guru mighty,
- Light Oil Ball: Motiv venom cobra
- Preferred Company: Radical
- Location: Germany
Re: To Oval or Not to Oval
the easiest way to get the perfect coordinates for a oval thumbhole is to use the ovalcalc. Downloadable from http://bowlingtrainer.topschi.de/compon ... erial.html.
poor english Sorry, but works perfect!!!
Thomas
PS:
Tha datas you need are: width, height and angle.
poor english Sorry, but works perfect!!!
Thomas
PS:
its not possible to drill a accurate thumbhole without measure the height oif the thumb.is it normal for to try to oval the back of the thumb in addition to the x and y axis? i had someone do that without actually measuring the height of my thumb.
Tha datas you need are: width, height and angle.
Ducati what else?
---------------------------------------------------------------------------------------
nice people press +