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 Post subject: drill bit
 Posted: Wed Apr 26, 2017 10:42 am Post Number: #1 Post
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can I use a regular drill bit to drill my bowling balls ?? I know people use a tipped carbide drill bit, but why I can't I use a regular drill bit ?? is there a reason ???


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 Post subject: Re: drill bit
 Posted: Wed Apr 26, 2017 8:25 pm Post Number: #2 Post
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Yes, you can - but it's definitely not ideal.

I experimented with a set of HSS bits for metal (Silver and Deming, etc) and the edge geometry/rake angle is not ideal for plastics. They can be grabby, especially when dealing with pitches. With a solid mill/drill and a slow feedrate, they will work (but hole accuracy/quality is not great).

Also bowling ball covers and cores contain mineral that will lead to premature wear. You can do a custom grind that will help, but that's additional work.

If you're drilling a few balls for fun, you can try standard bits or possibly even spade bits. For more frequent work, pick up the sizes you need in carbide designed to do the job. Most people will start with their thumb size, and 31/32" for finger inserts. Not a big expense.

Steve

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 Post subject: Re: drill bit
 Posted: Thu Apr 27, 2017 9:43 am Post Number: #3 Post
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Thanks for your answer , I'm just starter drilling my bowling ball just for fun and I don't really want to spend more money with tons of tools. As you said I will start with the basics drill bit like thumb and fingers grips.


Thanks much !!!!


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 Post subject: Re: drill bit
 Posted: Thu Apr 27, 2017 12:38 pm Post Number: #4 Post
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Normal HSS-bits does straight and accurate holes. They require a bit more care and different methods to operate. Heat is the enemy for cheap drill bits because it causes excessive wear. If you already have a decent bench grinder along with some other gear at home you can sharpen or even modify the drill bits by yourself. Ovaling is harder to do with standard drill bits.

Use slow speeds and cut only about 1/4-1/2" at a time to allow the drill bit to cool down. Use a vacuum cleaner to remove drilled material as you drill so it wont be blocking the drill bit which causes heat. Use a pilot hole especially if you are drilling excessive pitches. Many people starts with small hole and then go gradually up the size until the hole is large enough.

I have found that the good old machinist rule for pilot hole size works great for bowling balls: Use a pilot hole that is same size as the flat part on your drill bit. Attached please find a picture about the measurement.

If you want to drill with ease especially with old balls you can drill a large hole, then plug the hole with ball filler and drill the hole to the plugging material after few hours. Even my cheapest chinese S&D "HSS" drill bit set cuts that like cheese. 8-)


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 Post subject: Re: drill bit
 Posted: Thu May 04, 2017 2:37 am Post Number: #5 Post
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The reason I'm asking is because I'm a tool die maker and have a lot HHS drill bit so is easier for me to sharpen it and I also have all kind of sizes.

Thank you for your help


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 Post subject: Re: drill bit
 Posted: Thu Nov 29, 2018 12:38 pm Post Number: #6 Post
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regular bits will chip the edges at any speed as a matter of physics. the bowling style flare once it penetrates the shell the bit no longer in contact with the shell until you are pulling the bit out of the ball. a regular bit like this https://mechanicguides.com/best-drill-bit-for-metal/ will continue to be in contact with the shell throughout the whole drilling process so any debris that is coming out can get between the edge and the shell, more heat will be applied to the shell throughout the drill process and the fact the bit stays in contact if the bit moves or chatter even very minimally or slightly you will likely chip the shell around the holes up.......

I don't drill balls but I use to use a lot of shop equipment around resin and fiberglass and we had the same flare tipped bits to avoid tearing up the fiberglass or resin transfer mold. They are definitely worth the money.....you will likely ruing a few balls if you don't use the right tool......you can use a hand drill.

https://www.youtube.com/watch?v=MTb_3CkFki4 it's very helpfull video


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