Ball End Router Bits

[foxfish]

Man this is driving me mad! Who if anyone knows if there is a Ball End Router Bit for cutting enclosed track rails available?
Sure you can get 3/8'' 1/2" but I need 6.5 or 6.75mm 0r 7mm.
How about a custom one (note 1 not 10) any thing! I am fed up compromising, utilising & struggling :vangry

 

[Pastor]

Try phoning or emailing APTC they used to get custom bits done for us. Not cheap though, we were paying £50 ish back in the 90's. There is a guy in the states who does them cheaper, I'll try and find out some details

 

[Pastor]

This is the company Welcome to SFScarbide.com a site showcasing the custom tool making skills of our company established in 1921. $59 a throw

 

[metelin]

kitto makes them for 5/16'' (8mm) and 9/32'' (7mm). i suspect the 9/32'' will be just fine for 6.5-7mm shafts. they're not cheap at 65usd but with current exchange rate they're a down right bargain for you guys. i have some for 5/16'' shafts for 60usd.

here's kittos site Internet Custom Spearguns

steve

 

[foxfish]

Thanks guys - Pastor I am having problems navigating that site? Metelin the 5/16" is close but the slot is 6.35mm which is a bit too close for comfort with a 6,5mm spear.

 

[Pastor]

Try sending an email, I heard that is about the easiest way with them. The website didn't look the most helpful

 

[metelin]

Metelin the 5/16" is close but the slot is 6.35mm which is a bit too close for comfort with a 6,5mm spear.

i'm not sure if i understand what you mean by "slot" but 5/16'' is about 7.9mm and 9/32'' is 7.1mm. the ball cutters kitto and i have are about .030'' oversize which means the 9/32'' version will cut a 7.78mm track which i think will be fine.

steve

 

[foxfish]

Steve I really want to use a 6.5 spear, the shank of the cutter is 1/4" = 6.35mm. That will not leave much tolerance to stop the spear jumping out the slot. (the gap in the top of the track that the spear fins protrude)

 

[metelin]

i see what you mean, i don't know of any ball end cutters with a smaller diameter shank. an alternative would be to embed a tube and cut the top for the shark fins, might be less expensive than a custom cutter.

steve

 

[foxfish]

Thanks Steve but that is the sort of thing I have been doing & I want to move on.
I will get one in the end---

 

[settingsteel]

Hiya Fox, don't know how far ahead you are but I rip a 1/8 slot up to the trig mech (or route) then use this

Core Box Router Bits - Toolstoday.com - Industrial Quality Carbide Tipped Router Bits
the second one (3/16) which permits a 9/32 or 5/16 shaft thus making an enclosed track

 

[foxfish]

Tone tell me that again?

 

[settingsteel]

Sorry Fox where'd I lose you???

 

[foxfish]

Hiya Fox, don't know how far ahead you are but I rip a 1/8 slot up to the trig mech (or route) then use this

Core Box Router Bits - Toolstoday.com - Industrial Quality Carbide Tipped Router Bits
the second one (3/16) which permits a 9/32 or 5/16 shaft thus making an enclosed track

But that bit looks like it cuts a half circle not a full round?
I cant get my head around imperial measurements either - I want to fire a 6.35 or 6.5mm spear.
3/16 = 4.7mm
9/32 = 7.14
5/16 = 7.9mm

 

[settingsteel]

But that bit looks like it cuts a half circle not a full round?
I cant get my head around imperial measurements either - I want to fire a 6.35 or 6.5mm spear.
3/16 = 4.7mm
9/32 = 7.14
5/16 = 7.9mm

OK, first I don't think my experience building guns holds a candle to yours...and this is just based on what I have tried- ya know trial&error (bit more error than trial if you get my driftrofl) so take it for what its worth.

The half round will cut your groove for the spear to sit pretty in it, since the cutter is wider than your rip cut (1/4"- tight) it will create the "round"

Your spear is 7/32 (like riffe euro, right?) if so this may just do it for you. the shank on this bit is a snug 1/4" so rip a channel with your tablesaw a hair less than 1/4" (after you've made your trig slot) and at the depth you require for fins to protrode enough for them to engage wishbone-the riffe 7/32 fins may not function, as I have already tried it, unless you make your cuts extremely precise and intend to use only this size shaft- I like to leave about an 3/32 on the top part of the enclosed track (with the 7/32 shaft it will have to be shallower...which may weaken the top of the track), any thinner and it tends to crack, I also add some absorbing poxy to this area to reinforce it- once your rip cut is made run the half round thru it, the rip cut serves as your guide- this bit allows an enclosed track which will accomodate a 9/32(7.14mm which is what I would use) & 5/16 (7.94mm a better choice if shooting in rocks IMO) spear.

As an after thought you can probably use a 1/8" (first one on the list) but the shank is 1/4" but I know someone (forget who makes them 1/8") in a WCS perhaps you can grind/turn the shank down to 1/8" (maybe more work than what its worth)


[edit] found it Solid Carbide Mini Burs never used it, but the price seems right...buena suerte dude!

 

[land shark]

Just a dumb thought but wouldn't a dove tail bit work and reduce friction also you could put a flat stock Teflon or nylon in there easier and further reduce friction.

 

[foxfish]

Not dumb at all - might well work but you will still have the problem with the router bit shaft measuring 1/4'' (6.35mm) so if you are using a 7mm spear there wont be much tolerance to stop the spear jamming in the grove when you fire the gun?

 

[devondave]

Foxfish , just an idea , is it possible to drill a 6.5mm hole with an extension drill like for theading electric cable though wooden standard lamps etc ? Not sure how straight this would be or if a bit that small is feasible , also you probably need to drill the hole early in construction and then machine too it . Sorry if this is bol**cks but it's going to be hard to get a 6.5mm ball cutter with a smaller diameter shank !

 

[foxfish]

At the end of the day it would be easier to but a American imperial measurement spear & one of these ? Enclosed UHMW Track for Spearguns

 

[land shark]

just an idea , is it possible to drill a 6.5mm hole with an extension drill like for theading electric cable though wooden standard lamps etc

they have a tendency to wonder