Cheapass dovetail cutting - fly cutting style

[NeoTech]

Well i enjoy making fly cutter of different variations.. And then the need for making dovetails came up. Specificaly a dovetail for a sight mount on a air rifle ive been struggling with building for a better part of a year or so.

But ive figured.. why throw away **** ton of cash on dovetail cutter when you should be able to fly cut a external dovetil with a proper sharpened bit.. Have someone tried this??

[philf]

Well i enjoy making fly cutter of different variations.. And then the need for making dovetails came up. Specificaly a dovetail for a sight mount on a air rifle ive been struggling with building for a better part of a year or so.

But ive figured.. why throw away **** ton of cash on dovetail cutter when you should be able to fly cut a external dovetil with a proper sharpened bit.. Have someone tried this??

Hi Neotech,

No reason at all why it shouldn't work.

Years ago I made one for reconditioning the cross slide on my Super Seven. I brazed a triangular carbide insert on to a shank I'd turned up and then ground a bit of relief on the bottom. It worked perfectly and has been used several times since on other jobs.

Phil.

[PekkaNF]

Is this of any help?
http://www.cnccookbook.com/MTMillDovetail.htm

Pekka

[NeoTech]

It sure is. That wasnt one way i thought of doing it at all ;D

I was into making a bit looking like this,
And mounting it in a 20mm straight shank with some countersink screws. =)

[PekkaNF]

Sooooo.... I figured You want to grind a good size HSS blank or silver steel and bolt it onto 20 mm round shank?

But I actually tought of doing this too, because I seem to be missing always the "right" cutter. I envisioned some trouble getting the business end cutting angle right and straight, therefore I concentrated more to "buy accuracy" i.e. use something that has been manufactured right. Do you have TCG?

You could ofcourse bolt insert into holder and bolt that one into shank...I actually swing an insert lathe tool on my flycutter most of the time.

Any particular reason to grind this tool? Maybe other than 45 or 60 decree angle?

Pekka

[NeoTech]

Nah not really a good reason.. more than i have alot of HSS blanks now a days.. and ive made a small grinding jig for setting angles and so on..
But i do think that carbide tip on a proper toolshank is a better solution actually..

TCG, no idea what that is..

i have been experimenting with holding a small carbide insert tool in my fly cutters as well but i tend to break the tips more than once.

[PekkaNF]

Nah not really a good reason.. more than i have alot of HSS blanks now a days.. and ive made a small grinding jig for setting angles and so on...

That is actually one of the best reasons on my book

TCG, no idea what that is..

tool cutter grinder
Try that one on google  picture search - least looking all those different forms of TCGs keeps me entertained for hours.

...But i do think that carbide tip on a proper toolshank is a better solution actually..
i have been experimenting with holding a small carbide insert tool in my fly cutters as well but i tend to break the tips more than once.

I have good chunk of iron on MT3 and I put there baddest russian carbide bit I had (Somewhat bigger and thicker than CCMT09 with really BIG r) and never had a trouble.

The slender holder has been machined out of round rod (was easier to get angles right to something....that was long ago I forgot for what ).

The attached holder is a funny one....I needed to cut on recess, therefore I need small diameter flycutter. I got my boring bar later. Maybe this explains something.

Pekka

[NeoTech]

Hmm, that actually looked quite doable.. I gotta make a try.. This gave me some water on the mill.. (ooh swedish expression badly translated) ;D

[Jonny]

Assume its a 60 degree dovetail not a Picatinny or Weaver? Or both?
Done it in my early years and do have a handmade MDS the dovetails were cut exactly that way. Steel breach block held at an angle using conventional milling tools.

60 degree and 45 degree decent dovetail cutters are quite cheap. 3/8" from around £11 from J&L far from the cheapest place around. 1/2" price goes up, need to get some more.

[NeoTech]

For the sight rails i guess its a 45 degree, but i wanna give a try at making picatinnys as well for accessories.. =)

[Chrispy]

There was an article on this very thing several years ago in one of the US HSM magazines. It was for cutting a 60 degree dovetail with a flycutter. It talked about how to step the cut over and down to follow the 60 degree slope. I guess what you would call a type of manual CNC. I will see if I can find it and post what issue it was in.

[BillTodd]

Knocked this up a few year ago: (see pic)

Worked quite well with light cuts

[Jonny]

Problem there Todd  its got a load of radius on the tip.
Many European sorry German dovetails are not that deep some are only 1.8mm. Very few go deeper than 2.4mm.

So by using a rad on cutter there has to be clearance on the opposite fitment ie mounts. Even then if there is clearance allowed at best it will reduce grab and holding zero.

There is no industry standard for cutting dovetails amongst producers, in fact take a certain Fen and theres three different sizes on same product.

Picatinny/Weaver has an undercut 45 with recess, top 45 degree angle and slots. Inundated making them and not worth while.
Not a good system any way limited on mount position every 10mm if cant slide scope through the rings.