Munkul
Jack of some trades, Master of none
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- 7,372
- Location
- Cumbria
I did some boring last week at 7.6:1 ratio (25mm over 190mm stickout in my boring head) and it was pretty chattery... I got an acceptable finish with a very shallow DOC, but I'd like a much more rigid setup, specifically for doing deep holes at 40-50mm diameter.
I love the look of these, our machinist has one and the design is great, but I'm not splurging that kind of money on something that get used once a year!
I'm thinking of making a long solid boring bar at 40mm diameter held by a 40mm endmill holder, with about 220-230mm stickout to give around 5.5:1 ratio.
with one of two options:
1. bored hole for a 12mm cutdown boring bar in the crossways direction, secured with grubscrews in the bottom. I can adjust it using a flat faced dial indicator for reference.
Upsides: Free (I just need to machine a bit of material and cut a cheap boring bar down)
Downsides: Very fiddly to adjust. Won't bore blind holes.
2. Machine the end to accept a 38mm small adjustable boring head like this one:
Upsides: Adjustable and a lot easier to use.
Downsides: costs money for a chinese quality boring head. Also have to buy a spare 8mm bar to use with it. Not as rigid as option 1.
Either way, I have a dogbone to machine soon that if I do both sides in one setup, I'll need that 220mm stickout.
The mill itself is fairly rigid, it's a 2.5t bed mill with an ISO40 spindle.
Anyone with "boring" experience care to add their tuppence?
I love the look of these, our machinist has one and the design is great, but I'm not splurging that kind of money on something that get used once a year!
Finish Boring Head With Weldon Shank - THKB Series (Teknik)
The Teknik THKB series boring system that is suitable for finish boring applications from 25mm up to 80mm. This is supplied with a weldon shank (can be used on any machine spindle with side lock arbor). This is suitable for use with CCMT and CCGT inserts. (see below for applicable heads and...
www.cutwel.co.uk
I'm thinking of making a long solid boring bar at 40mm diameter held by a 40mm endmill holder, with about 220-230mm stickout to give around 5.5:1 ratio.
with one of two options:
1. bored hole for a 12mm cutdown boring bar in the crossways direction, secured with grubscrews in the bottom. I can adjust it using a flat faced dial indicator for reference.
Upsides: Free (I just need to machine a bit of material and cut a cheap boring bar down)
Downsides: Very fiddly to adjust. Won't bore blind holes.
2. Machine the end to accept a 38mm small adjustable boring head like this one:
38mm Boring Head and Arbors - Arc Euro Trade
ø38mm metric boring head with a choice of arbors. The head is suitable for ø8mm shank boring tools which can be mounted in three different positions.
www.arceurotrade.co.uk
Downsides: costs money for a chinese quality boring head. Also have to buy a spare 8mm bar to use with it. Not as rigid as option 1.
Either way, I have a dogbone to machine soon that if I do both sides in one setup, I'll need that 220mm stickout.
The mill itself is fairly rigid, it's a 2.5t bed mill with an ISO40 spindle.
Anyone with "boring" experience care to add their tuppence?