Boring bars with inserts...??

[56type]

Been looking at a few of the small boring bar sets on ebay & amazon as well as the threading bar and was wondering if anyone here could recommend for or against the purchase ?? Looking to use them to do internal threading/boring to make accessories for my Atlas 101000 Mk.2. The Insert on the threading bar in particular looks to be too small to cut larger threads to depth, say in the 1-10 TPI range for a spindle protector or making a face plate as an example. Though having never owned or used one I'm not sure what is capabilities/limitations would be. Thanks

 

[mikey]

Sure would help if you linked to the set you're considering.

 

[56type]

Sure would help if you linked to the set you're considering.

Sorry about that...Here's the one set I'm looking at... Do I need the dedicated threading bar or are there inserts that would allow threading with boring bar set ?? The pockets for the inserts seem to be cut slightly different between the boring bar set & threading bar.

https://www.ebay.com/itm/1PC-SNR001...610056?hash=item23c86f9088:g:PnkAAOSwvehdptMH

https://www.ebay.com/itm/4pc-6-7-8-...951263?hash=item1f14fa8f9f:g:1yMAAOSwZXRfOlEC

 

[NortonDommi]

Boring bars and threading bars have different seat angles on the triangular inserts - not interchangeable, at least all the ones I've seen. Look at what you want to do. For threading you will need dedicated holders and inserts. Good news is one threading toolholder can accept a number of insert sizes and profiles.
Both of those are good value. We would all love to have solid Carbide, damped,through hole lubrication bars but I for one have to settle for 2nd hand and/or budget Chinese stuff off E-bay and thank the wonders of mass production for making them affordable.
Size bars to the job and the thread.
Look at a left hand threading bar as threading out of the hole is a lot easier than threading in.(you can use RH external inserts).
Joe Pi did an excellent video on this.

 

[MrWhoopee]

The 11IR insert will cut 16-48 tpi, so no it won't cut a 10. The biggest bar in those links is 10mm Ø, so not a lot of rigidity. Small bar means limited depth and cutting capacity. I wouldn't discourage you from buying them, but I would suggest you'll probably want some bars that use the 16IR insert too. I have nice assortment of the tools like you've linked and have been very happy.

 

[erikmannie]

I just bought 4 Aloris long boring bars (BL series) and 3 Aloris threading bars (ATB series). I had to buy 5 different types of inserts for those.

Aloris is a very helpful, expedient & professional company to deal with. The items are beautiful, but they did not come cheap.

 

[mikey]

Choosing boring bars can be a little complicated because there are a lot of "it depends" thrown into the mix. For example, in that set you linked to with the 4 bars, the largest is 10mm and the deepest theoretical depth you can go with it is only about 1.5". This has to do with the fact that it is a steel bar. If you need to go deeper then you either need a larger diameter bar or you need to go with a carbide bar and that is going to get expensive. So, how big is the bore and how deep do you need to go because the size and bar material you choose depends on that.

If you plan on doing a lot of boring then I suggest you stick with an inserted carbide bar and try to buy solid carbide bars if you can afford them. If you don't plan to do a lot of boring and still want good quality bars then I would go with Micro 100 solid carbide bars suitable to the bore and depth you need. They are also somewhat expensive but will last you for decades if you take care of them. If you are really strapped for cash then stick with the SCLCR bars that are a dime a dozen (like that set you linked to). Most cheap ones are steel so you still only have a 4:1 extension capability but they come in a large range of sizes and you can buy whatever you need for cheap. Inserts for these bars are also cheap.

The other thing to consider is the bar geometry. If you need to bore a blind hole then a positive lead bar is better than a zero lead bar, and this goes for both inserted and solid bars so again, it depends. Zero lead bars are fine for through bores.

As for internal threading, yes, there are bars that take boring, grooving and threading inserts. I like and use the Circle Machine QCMI series bars for just this reason. However, they are somewhat expensive and not something the typical hobby guy needs. It is much cheaper to buy a steel inserted carbide internal threading bar and if you go this way, I highly recommend Carmex. They make inserts that will handle a 1-10 tpi thread (16 IR G55) and the same bar will handle different inserts so they're versatile. OR you can buy a solid carbide Micro 100 internal threading bar suitable for 10 tpi that will go deep enough; these tend to cost almost what an inserted bar costs but they are very, very high quality and will last for a long time. So, it depends on your budget and needs.

Sorry about this but you are getting into an area in which your needs are going to dictate the tools you buy. And the greater the precision you require, the more it will cost you. That being the case, be very sure of what you need and buy bars and inserts that will suit that need.

Boring is one area where I think that knowledge is a prerequisite for tool buying because mistakes can be really expensive so if you are not sure, ask first. The guys will steer you right.

 

[benmychree]

I have posted, perhaps all too many times, that there is nothing wrong with boring tools and bars that use hand ground tools; I especially like boring tools made by the Bokum Tool Co., they are made in many sizes and types, for lead angle boring, flat bottom boring and threading; all are made of HSS, and some are carbide tipped, all are form ground and are sharpened only on top, so that the form is always true, and they are quite long lasting if carefully sharpened, the larger sizes have a soft steel shank and screw on cutting heads. Look for them on E Bay or, buy new if you have a generous tooling budget. They are easily sharpened by hand (carefully) and they made fixtures for sharpening them on a surface grinder.

 

[56type]

Choosing boring bars can be a little complicated because there are a lot of "it depends" thrown into the mix. For example, in that set you linked to with the 4 bars, the largest is 10mm and the deepest theoretical depth you can go with it is only about 1.5". This has to do with the fact that it is a steel bar. If you need to go deeper then you either need a larger diameter bar or you need to go with a carbide bar and that is going to get expensive. So, how big is the bore and how deep do you need to go because the size and bar material you choose depends on that.

If you plan on doing a lot of boring then I suggest you stick with an inserted carbide bar and try to buy solid carbide bars if you can afford them. If you don't plan to do a lot of boring and still want good quality bars then I would go with Micro 100 solid carbide bars suitable to the bore and depth you need. They are also somewhat expensive but will last you for decades if you take care of them. If you are really strapped for cash then stick with the SCLCR bars that are a dime a dozen (like that set you linked to). Most cheap ones are steel so you still only have a 4:1 extension capability but they come in a large range of sizes and you can buy whatever you need for cheap. Inserts for these bars are also cheap.

The other thing to consider is the bar geometry. If you need to bore a blind hole then a positive lead bar is better than a zero lead bar, and this goes for both inserted and solid bars so again, it depends. Zero lead bars are fine for through bores.

As for internal threading, yes, there are bars that take boring, grooving and threading inserts. I like and use the Circle Machine QCMI series bars for just this reason. However, they are somewhat expensive and not something the typical hobby guy needs. It is much cheaper to buy a steel inserted carbide internal threading bar and if you go this way, I highly recommend Carmex. They make inserts that will handle a 1-10 tpi thread (16 IR G55) and the same bar will handle different inserts so they're versatile. OR you can buy a solid carbide Micro 100 internal threading bar suitable for 10 tpi that will go deep enough; these tend to cost almost what an inserted bar costs but they are very, very high quality and will last for a long time. So, it depends on your budget and needs.

Sorry about this but you are getting into an area in which your needs are going to dictate the tools you buy. And the greater the precision you require, the more it will cost you. That being the case, be very sure of what you need and buy bars and inserts that will suit that need.

Boring is one area where I think that knowledge is a prerequisite for tool buying because mistakes can be really expensive so if you are not sure, ask first. The guys will steer you right.

Thanks for the explanation on how to select what I'm going to need. I went to the carmex site where I found a PDF explaining/decoding the the inserts. http://www.carmexusa.com/contentonl...ch/003-057_thread_turning_inserts_holders.pdf I found the 16IR G55 insert you mentioned on pg. 5 partial profile 55 degrees, it lists TPI as 14-8. Yet on pg.11 under UN- Unified UNC, UNF, UNEF, UNS I see a 16 IR 10 UN that lists pitch TPI as 10. So which would be the better insert to choose for making the thread protector for the Atlas 10100 Mk.2 with the 1-10" spindle thread ??

I was browsing the threading bar section and came across a listing for the SIR 0013 M16 internal boring threading bar on pg. 5 http://www.carmexusa.com/contentonl...052_Thread_Turning_Toolholders_and_Kits_M.pdf, Would that be the correct bar for the needed inserts to cut the 1-10" thread ?? Thanks.

 

[mikey]

I cited the wrong insert, which was a Whitworth 55 degree insert - my mistake. You need a 60 degree insert and a partial profile insert for 8-14 tpi would be a 16 IR G60 but I do not know which tool holder takes this insert. The full profile inserts are a lot more specific regarding tpi because they cut the proper root and crest profile at the same time so you need more specific advice on these.

Used to be a seller on ebay who sold Carmex tools and I would write them to find the right tool holder; they no longer sell on ebay so my personal approach at this point would be to contact Carmex directly and ask them for advice on which tool holder and insert they would recommend. My experience with contacting the manufacturers has been that they are usually very responsive and helpful. The reason I am hesitant to take a guess is because your money is involved and I would rather you get the info from a reliable source.

Call Carmex (888-628-5030), tell them the material you're cutting, the bore size and tpi you need. They will tell you exactly what to get. Sometimes it is cheaper to buy directly from the manufacturer if they sell to the public so you might ask what they charge.