Coventry Easychange Tool Holders

[Anonymous]

I have a Tormach CNC mill with an R8 spindle. Tormach have a proprietary tooling system (TTS) which uses 3/4″ plain shank holders and a special 3/4″ collet. The holders come with an integral collar that is pulled up against the spindle nose to give repeatable Z heights. The system is fine for drilling, machine tapping and light milling. However, I have had some issues with holders pulling out under heavy milling cuts.

 

As a replacement system I’ve been looking at the Coventry Easychange tooling system.

 

http://www.coventrytoolholders.co.uk/prods-easychange.htm#1

 

 The blurb says not suitable for heavy cuts. I have had varying viewpoints on professional machining forums as to whether the 1.5hp motor in the Tormach is capable of what would be regarded as a heavy cut. Given that the Coventry system is supposed to be for professional use I would have thought it would be fine with what is a fairly low power mill.

 

The system is not cheap though, and before I make a decision, I wonder if anybody here has any practical experience of this system, with either CNC or manual machines.

 

As a secondary consideration the Coventry system should be quicker for toolchanging. It can get real tedious when changing tools every few minutes on the CNC mill having to loosen the drawbar, change the tool and then retighten the drawbar each time.

 

Regards,

 

Andrew

[Anonymous]

[David ColwillParticipant @davidcolwill19261]

I use this system on my manual Bridgeport clone (2hp I think) and have had no problems so far, that said I only use up to 20mm endmills and don’t  take very heavy cuts. There is a locking screw fitted which the instructions say should be tightened when you are working at the upper limits. Also I think that Denford Easimills were 1.5 hp and they used them. They certainly speed up tool changes for the sort of things I do and have the advantage of not requiring excessive z  clearance to remove them.                            

[David Clark 13Participant @davidclark13]

Hi There

I have used them.

Great for drilling, came out of the holder when tapping though only on reversing out of hole. Ok for milling but keep the cutters below 12 mm and light cuts. They oscillated around but that could have been the head on my mill.

My version was genuine Easychange but did not have an allen screw.

J&L Industrial sell them.

Contact your area representative and ask for a massive discount.

regards David

 

[Anonymous]

Hi Guys,

 

Thanks for the information. Interestingly it pretty much mirrors that I’ve been given on other forums. The system is good, but it will not cope with heavy cuts. On the CNC mill I tend to run as close to the power limits as I can. Somehow I just can’t see the Coventry system coping with that. The taper seems too short and too far away from the cutting forces to be stable under high cutting loads. I wonder if it is telling that the manufacturers own leaflets emphasis the ease of changing from centre drill to drill to chamfer tool, with ‘nary a mention of milling?

 

While the time saved in tool changes would be welcome, I don’t think the cost of the system is justified if I cannot also use it for heavy milling. Currently I use a Clarkson lookalike chuck with a rippa mill for roughing and use the TTS system for finish milling, drilling and tapping. I use a tension/compression head for tapping and hence use reverse spindle to extract the tap. Not too helpful if the tool holder unlocks!

 

The drawbar and washer that came with the Tormach were not of the best quality, so I suspect that making a new drawbar and washer out of hardened silver steel may be a relatively cheap way of increasing drawbar pull and thus easing the problem of the TTS holders pulling out.

 

Regards,

 

Andrew

[Author]

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