Boring head – Quality

[Boiler BriParticipant @boilerbri]

[Boiler BriParticipant @boilerbri]

I have a jones and shipman boring head on a morse taper. It is very good quality and serves well.

I want one on a R8 collet style to fit my Milling machine.

What's the quality like on the ones from RDG?

Brian

[Jim CParticipant @jimc]

Brian,

You could just get a morse taper to R8 converter.

Jim.

[Jim CParticipant @jimc]

John,

Why would you need the morse taper to be pulled into the adaptor, surely it will be held there by good old friction?

Jim.

[Boiler BriParticipant @boilerbri]

Thanks for the replies.

I looked at an adaptor, but i think the same way, and do not want to chance it dropping out. Only because i hate making parts twice.

Some of the copy parts tend to be a little different in fit.

Bri

[JasonBModerator @jasonb]

Posted by Jim C on 28/04/2012 18:58:50:

John,

Why would you need the morse taper to be pulled into the adaptor, surely it will be held there by good old friction?

Jim.

Same reason as any MT or R8 tooling needs to be held into the taper with a drawbar when milling the side forces and or intermittant cuts can loosen teh tapers grip and your tooling drops out. MT tailstocks tend to only have an end loading so you don't need a drawbar.

Bri like John I use a Chronos one which is much the same as RDG, does the job fine though the build quality may not be quite as good as the named brands.

Edited By JasonB on 28/04/2012 20:11:33

[SpringbokParticipant @springbok]

What was that silly childrens film and there was also a few comedy rip off's "may the force be with you" if you do not use a drawbar in the quil it will loosen and drop with dire results to your work . Haveing a MT or otherwise taper in tail stock and in a mill are 2 different issues Both are working on different forces so please use a drawbar in a vertical mill at all times. There are many convertors and both names have been mentioned that I am familliar with and all seem good/average quallity If you can turn or mill down to the Nth .00000 good luck but for the average person like myself who regards being in my workshop as fun .002 is a victory.

Have a good sunday everyone getting started to let all the hens out, cockerells starting and other animals fed, then me and back in workshop.

Bob

[LambtonParticipant @lambton]

As a firm believer in "you get what you pay for" I bought a British made Arand boring head some years ago and I have been very pleased with it. Most equipment of far Eastern origin will do the job and I fully appreciate that many model engineers have a limited budget, however my advice is always to buy the best you can afford as the quality will remain long after the price is forgotten.

[Tony Pratt 1Participant @tonypratt1]

I have secured my 2MT boring head into an R8 adaptor with a reduced head cap screw which passes through the 7/16" UNF R8 adaptor draw bolt hole and screws into a threaded sleeve in the MT 2 boring head.

Tony

[MadMikeParticipant @madmike]

Hi Boiler Bri, I have been looking at the RDG boring heads with both 2 and 3 MT. They are threaded for a drawbar, and their on line catalogue tells you the thread so that you can select the correct one. I haven't checked Chronos or anybody else but like an ER collet chuck you will neeed to secure the boring bar if it running vertically to avoid the risk of it falling out. The reasons given by some others on here are spot on.

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Apart from what might be considered 'quality' in terms of finish and accuracy of adjustment there are several things to look for in a good boring head .

(1) Size of shank relative to body size of boring head . For any given size of shank there is a maximum safe size for boring head body . Put another way an R8 (eg) shank can carry a much bigger boring head than a 2MT . It all comes down to rigidity .

(2) Means of fixing boring head body to shank . Screwed in is worst and machined integral is best . Rigidity again .

(3) Stack up height . How far is the outer tool holding face from the machine nose and how many fixed and moving parts are there in the stack up between . Shortest distance and least parts is always best . Rigidity again .

Don't dismiss the effects of the above – difference in rigidity of two superficially similar boring heads – one with all the best design features and one with all the worst can be by a factor of at least 10 .

Notes :

(a) A boring head needs to be positively retained in machine spindle in any orientation .

(b) A good way of designing a boring head to be used on a lathe is to have it backplate mounted like a chuck rather than put it on a small shank . .

Edited By MICHAEL WILLIAMS on 29/04/2012 19:23:38

[KWILParticipant @kwil]

Springbok, is that 0.002, metric or imperial?

[Anonymous]

I suspect it's a dimensionless number, relative to a smidgen – Andrew

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