Need help identifying this toolpost

[T Bredehoft]

I'd use half hard (28-32 RC) 4140. Its' readily available, easily worked (with patience) and holds up well in service. It makes O1 look like ledloy as to work-ability.

 

[fratskop]

I'd use half hard (28-32 RC) 4140. Its' readily available, easily worked (with patience) and holds up well in service. It makes O1 look like ledloy as to work-ability.

thanks for your help. here in europe we know 4140 as 42CrMo4 (the DIN standard) ive worked with it a few times. not super hard but also not very soft but machines great and shines nice. it seems the next project for my mill is sorted.

 

[Toolmaker51]

fratskop says "I guess it comes closest to a CA at 4 inches (or 101.6mm) but i cant find any dimensions of the dovetail itself, only Total width and height. I could try to make Some myself but i dont really trust myself that much with stuff like that since ive never done it before "

I've singled out certain parts of that statement.
No one here can say they never said or thought one or more of those. Every single job looked at gets that same perusal, regardless level of expertise.
Learning is composed of not less than 2 elements, one is initiative.
The other depends on the person. . .
There is good news. There are numerous helpful members here, and other toolholders WAY harder to replicate!

 

[fratskop]

No one here can say they never said or thought one or more of those. Every single job looked at gets that same perusal, regardless level of expertise.
Learning is composed of not less than 2 elements, one is initiative.
The other depends on the person. . .
There is good news. There are numerous helpful members here, and other toolholders WAY harder to replicate!

it's not that i dont trust myself in making one, its just that i get scared easily when making parts like this.but hey, there's a first time for everything right? at work i am a CNC miller and have done way more complicated stuff than this but no matter how simple the part i handle it with a certain caution, ya never know what could go wrong

 

[Latinrascalrg1]

I find it helps breaking the project down into easily obtainable smaller projects.....makes it seem much less overwhelming.

 

[WCraig]

Can you show how the clamping piston works? I would guess it is retracted in the pictures above. What does it look like when it is extended?

Craig

 

[Superburban]

side note: i also find it very weird that the clamping pistons are only on one side and not central, what makes even less sense to me is that they are on the 'back' side of the dovetail because to me it seems logical to put them on the front side so the clamping force is closest to where the cutting forces will take place

KInda neat that it has separate clamping pistons for each side. Think about this. The piston wether it locks by moving inward, or outward (I'm voting on inward), it will force the whole height of the dovetails on the front edge, to lock together, giving a strong clamping force on the front edge. The rear end will just have the area of the piston, providing the clamping. Except for the challange of finding holders, I think I like the design.

 

[MontanaLon]

That seems to be a very well thought our design and a simple way to create dovetails requiring only a V-block and a straight mill.

Thinking about it just a little I bet the sliding dovetail lock is a parallelogram wedge type that pushes the dovetail wedge into the body and keeps it aligned no matter how much it is tightened. It also pushes it out when loosened. If you get a chance to take it apart, I would love to see what makes it tick. It took some serious planning to set up but was likely done with very limited machining steps.

 

[Latinrascalrg1]

I agree, id love to see what makes it work inside!

 

[fratskop]

That seems to be a very well thought our design and a simple way to create dovetails requiring only a V-block and a straight mill.

Thinking about it just a little I bet the sliding dovetail lock is a parallelogram wedge type that pushes the dovetail wedge into the body and keeps it aligned no matter how much it is tightened. It also pushes it out when loosened. If you get a chance to take it apart, I would love to see what makes it tick. It took some serious planning to set up but was likely done with very limited machining steps.

I planned on taking it off anyway because as you can see in the picture it could use some cleaning