Dovetail myth regarding pin dimensions.

[WobblyHand]

Sorry, can't provide a link, It is what came with the tool when I opened the box. I did buy an "extra" set of holders after the fact, This might explain why I had to buy and return 2 sets before getting the right ones. I had thought in those cases it was just me not really understanding the nomenclature, suppose that really is the case but....?
I have dealt with cases like this before but only on VERY expensive tool sets where they don't want anyone messing with their I.P. For some odd reason, I don't think that is the case here?

I think the IP related to QCTP is totally out of the barn. Everyone makes them. _XA tool holders are copied world wide. Just checking on eBay, AXA-1's (250-0001) are under $10 in quantity. BXA-1's are $12.50-$15 in quantity. Bigger tooling CXA, etc. costs more. Now these aren't as nice as the real thing, but they are plenty good enough for most hobbyist use. I have bought real Aloris tool holders for the one's that no one seems to clone, the AXA-4D and the AXA-8 and they are great. They all fit my generic AXA QCTP, clones and Aloris, with no issue. They all have the same angle dovetails.

 

[RJSakowski]

That was the point. There is no I.P. to protect but if you make a tool post that was different enough from the _XA tool posts, then everyone that bought one would have to buy tool holders from you.

 

[WobblyHand]

That was the point. There is no I.P. to protect but if you make a tool post that was different enough from the _XA tool posts, then everyone that bought one would have to buy tool holders from you.

I fully understand the point.

My suggestion was to break away from a proprietary tool post. Now that all depends on how much has been spent on things already (the sunk cost). But if one stays with a proprietary tool post, you have to either make your own, or modify things, or pay the man for the proprietary goods. There's probably other options, but those are what immediately come to mind.

 

[twhite]

Might be a really stupid question. Here goes. What about simply machining the tool post to 30deg. That is if all the holders you have been trying are too tight of a fit.


Cutting oil is my blood.

 

[WobblyHand]

Might be a really stupid question. Here goes. What about simply machining the tool post to 30deg. That is if all the holders you have been trying are too tight of a fit.


Cutting oil is my blood.

This is not a stupid question. Think it's a very good question. Basically, can the tool post be modified to accept "industry standard" holders?

 

[Bruce Billett]

Might be a really stupid question. Here goes. What about simply machining the tool post to 30deg. That is if all the holders you have been trying are too tight of a fit.


Cutting oil is my blood.

My good man, the only stupid question I have run into to date is " How far is it from here to the nearest star man has tried to contact, in INCHES plus or minus the orbit of the earth around the sun?". By the way I ask that one a lot just to see the reaction I get. I also used to work Radar Maint. so we had a lot of time on our hands, So one night me and one of our computer troops sat down and figured it out. I can tell you THAT is a LOT of zeros! Three pages of them! Came to the conclusion the correct answer is...
Wait for it..
2. As in TOO far!!
This is not a stupid question, I contemplated it myself.
The reason I did not look into this closer is that I would then need to modify all my existing tool holders to fit the 30 deg. and while I didn't put a LOT of thought into it, I felt that somewhere along the line either the tool post or the tool holder would grow in size and not fit anymore, So rather than risk my tool post and holders so I ended up with NO way to mount a tool. I thought I would look to this forum for sage advice.
That turned out to be what I feared. Buy a good set. Which is OK as that is what I thought I would get. It will be a week or so until my new post and toys arrive, But I am still operational.
When the new toys arrive, I will try to mod. the existing tool holders to 30 deg. If I fail? Well I'm not out anything. If it works, I get freebies!!

 

[RJSakowski]

I'm sorry I should have recapped. I am trying to make a female dovetail to match my quick change tool post. The issue was trying to match a dovetail and the complicated way to determine where to cut the part so they matched the existing dovetail. Matching pins sized to the existing dovetail. and all the math involved. Just wanted to know why when it seemed to me that knowing the angle, depth, and width of the throat one could simply cut the dovetail to match. Silly me, I assumed that the world used a 30 deg. angle for most all dovetails. Never guessing that the Chinese were using the Wentworth angle scale where it is NOT 30 deg. but 26 deg.? I found this out buy going through all the bother of the pins Etc. only to not even come close. Thinking this is me not truly understanding what all that was about, I tried my way. It was a much closer fit, but something wasn't right? I looked down the dovetail as it SORT of fit and noticed that the two facing surfaces were not even close to parallel? What? Only thing I could think of was that the angles were different. So I pulled out my rough scale and sure enough NOPE!! So I pulled out my rather accurate scale and what I cut was in fact 30 deg. which is what the cutter said. So next I measured the angel on the tool post thinking it might be off. Well that came in at 26 Deg. So now my quest is two fold. 1) find out if it's the drugs, and it is supposed to be like this. Or 2) find out how to correct this, either by buying American made tool post and holders that are 30 Deg. or find a 26 Deg. bit. I'm not finding a 26 Deg. bit? Don't relish the idea of paying >$100.00 for a custom bit. AND I have NO where near the ability's to grind my own!
So I'm fishing for thoughts on the matter.
Thank you.

Can you explain what method you used to measure the dovetail angle? I am curious as an AXA tool holder has about .3" of length to use as a measured surface and I would think that it would be difficult to make that measurement accurately in a hobby workshop. Also, I am unfamiliar with the "Wentworth angle scale". Would you mind explaining what it is and how it is used? If you were referring to the Withworth thread angle, that angle is only used in conduction with a British thread standard and and has no basis for general thread measurement.Even so, the half angle of a Whitworth thread is 27.5º.

 

[Bruce Billett]

Can you explain what method you used to measure the dovetail angle? I am curious as an AXA tool holder has about .3" of length to use as a measured surface and I would think that it would be difficult to make that measurement accurately in a hobby workshop. Also, I am unfamiliar with the "Wentworth angle scale". Would you mind explaining what it is and how it is used? If you were referring to the Withworth thread angle, that angle is only used in conduction with a British thread standard and and has no basis for general thread measurement.Even so, the half angle of a Whitworth thread is 27.5º.

OOPS it was Withworth! The Wentworth angel scale is a joke. I had a friend that got a HiIlman Minx. It was built on the Wentworth system. Very close to metric and very close to Imperial, Yet different enough that nothing fit it. Bolts would go in 3 or 4 turns and then stop. Real bother to find parts! The only place he could find parts was J.C. Whitney in Chicago. It even went so far as to have a 6 volt Pos. ground, So radios etc. had to be modified and isolated to work. Inside joke, sorry about that.
General tool makes a pretty nifty protractor/angel finder That really gave me what I need to know, but I wanted to know for certain, So next I turned to my iPhone and an App called angel finder. I have found this handy for measuring angels in hard to get at locations and found it surprisingly accurate. It confirmed my first shot at it. Then I turned to a Mitutoyo 187-904 angel finder that I picked up cheep from the estate of an old machinist that is nothing short of hypertensive accurate and got final confirmation of the angel. They all agreed so That is what I took away. It was very easy with the phone app. and the General tool Tool was also pretty easy both accurate enough for the home shop. The last one was much more because I had it. Since I really have no use for a tool like that I decided it was time I used it. Fun in the end, but not worth the effort let alone the money to buy one new. I got it because the guy had been a friend of mine and it was something to remember him by.

 

[RJSakowski]

OOPS it was Withworth! The Wentworth angel scale is a joke. I had a friend that got a HiIlman Minx. It was built on the Wentworth system. Very close to metric and very close to Imperial, Yet different enough that nothing fit it. Bolts would go in 3 or 4 turns and then stop. Real bother to find parts! The only place he could find parts was J.C. Whitney in Chicago. It even went so far as to have a 6 volt Pos. ground, So radios etc. had to be modified and isolated to work. Inside joke, sorry about that.
General tool makes a pretty nifty protractor/angel finder That really gave me what I need to know, but I wanted to know for certain, So next I turned to my iPhone and an App called angel finder. I have found this handy for measuring angels in hard to get at locations and found it surprisingly accurate. It confirmed my first shot at it. Then I turned to a Mitutoyo 187-904 angel finder that I picked up cheep from the estate of an old machinist that is nothing short of hypertensive accurate and got final confirmation of the angel. They all agreed so That is what I took away. It was very easy with the phone app. and the General tool Tool was also pretty easy both accurate enough for the home shop. The last one was much more because I had it. Since I really have no use for a tool like that I decided it was time I used it. Fun in the end, but not worth the effort let alone the money to buy one new. I got it because the guy had been a friend of mine and it was something to remember him by.

I asked because you had piqued my curiosity so I used my 60º fishtail gage to check some of my 60º ways and found what looked like a deviation. I decided to make a 60-60-60 triangle from some 5/16" aluminum plate, using my RT. I chose the triangle because the sum of the three angles is exactly 180º and if the angles are equal, they will necessarily be 60º. Also the three sides will be equal which can be verified by direct measurement with a micrometer. Curiously, the ways on my RF30 clone and on my Grizzly G0602 both checked out as 60º but the way on my Tormach CNC, the angle is somewhat less than 60º. This, of course doesn't affect functionality of the mill and there is never any need for aftermarket parts but it does raise the question as to why. The mill is Chinese made but made to Tormach specs. and inspected by Tormach so the question arises as to why that angle.

 

[Parlo]

55 degrees was often quoted as the optimum dovetail angle for machinery slides.