Installing a wedge QCTP on the HQ800V

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spro
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Re: Installing a wedge QCTP on the HQ800V

Post by spro » Fri Apr 21, 2017 9:30 pm

I'm losing it now but if you are talking Tee slot, it should be full length with a few threaded holes along the length. I would never present a small T nut into the compound. The pressure to secure the tool post and in work can fracture it.

John R
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Re: Installing a wedge QCTP on the HQ800V

Post by John R » Sat Apr 22, 2017 5:30 am

Thanks Torch

Torch
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Re: Installing a wedge QCTP on the HQ800V

Post by Torch » Sat Apr 22, 2017 7:48 am

spro wrote:I'm losing it now but if you are talking Tee slot, it should be full length with a few threaded holes along the length. I would never present a small T nut into the compound. The pressure to secure the tool post and in work can fracture it.
Spro,

Thanks for your words of caution.

The adapter plate I made is affixed to the table with 4 tee nuts, one at each corner. Excessive force is not required to keep it firmly in place. It is also indexed to the slots with milled keys on the underside. The compound is then bolted to the adapter plate with two bolts into tapped holes in the adapter plate.

The tool post is secured to the compound with a single bolt up the centre. But that is the nature of the beast; part of the original design of both the tool posts and the compound. Given that the tee-nut is pulling the flanges of the tee-slot up against the flat base of the tool post, which completely surrounds the bolt, I think the forces are entirely compressive and that no leverage is applied against the compound's tee slot flanges that might fracture them.

Unless perhaps a chip was left on a surface during assembly, but of course all surfaces should be cleaned off before assembling things, so that should never happen in the normal course of events!

spro
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Re: Installing a wedge QCTP on the HQ800V

Post by spro » Sat Apr 22, 2017 8:04 pm

Firstly, I do appreciate your message. It explains the reasons. I am but one little voice here and not able to test the strength of your particular compound metal. I have some responsibility here to note certain things. I was around people in my other life who held key information away from those who they considered a threat to their position. It was very costly in the long run. Nothing really good came from it. I liked them anyway and wouldn't harm them. If they see this as weakness, they don't know what is later. So then we have a compound slide on a lathe. I have some experience with the cast iron from there compared to semi steel cast here. It is different or it was. My Tai (hmm :) ) lathe has hardened bed ways yet I was able to hack the cross slide with a simple hacksaw. You can notice the relative thickness of every part much thicker than an Atlas lathe or any other older lathe of the same swing. This thickness arrives the center point higher than would be expected from a similar fine grained or semi steel slide combo. This same iron is the slotted compound and I wouldn't trust a small Tee nut in there with that large tool post. You are set for serious business here and that small T nut isn't right. Okay you already made it broader and that is good.

Torch
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Re: Installing a wedge QCTP on the HQ800V

Post by Torch » Sat Apr 22, 2017 9:45 pm

spro wrote: I am but one little voice here and not able to test the strength of your particular compound metal.
I hope to hell I don't test the strength of the metal either!!! :lol:

I made these mods a few years ago. All I can do is quote the immortal words of the guy who fell off the roof of a 20 story office tower. As he passed the 10th floor he was heard to say "Well so far, so good".

spro
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Re: Installing a wedge QCTP on the HQ800V

Post by spro » Sat Apr 22, 2017 11:30 pm

I'm not following this, I'm sure it is good but I'm a bit dumb.

Torch
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Re: Installing a wedge QCTP on the HQ800V

Post by Torch » Sun Apr 23, 2017 6:14 am

Spro,-

Sorry, sometimes my sense of humour is a bit obscure. My bad. Let me explain:

The ultimate test of the metal would be to apply increasing stress until it deforms or breaks. Hence "I hope to hell I don't test the strength of the metal", meaning I hope not to break or deform it.

The 'parable of the falling man' (as it were) was meant as an illustration that even though my setup hasn't failed yet, it could be headed in that direction. Given your experience and concerns, I will reevaluate the my setup and ensure the likelihood of failure is minimized.

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