Poor Mans Dovetail---

[Brian Rupnow]

I have been thinking about making a quick change toolpost for my lathe. This of course requires a dovetail milling cutter. I just priced a dove tail milling cutter yesterday, and it would cost $70. Last night, as I lay in bed fighting my chronic insomnia, I got thinking about alternate ways to come up with a dovetail. I want the end result to look like this,

 

[Brian Rupnow]

And of course, it would disassemble into two peices which look like this---

 

[Brian Rupnow]

And---having far more time than money these days, I thought---Why couldn't I make it out of individual peices as shown, and use dowel pins and 1/4" SHCS to assemble the peices.

 

[kuhncw]

Hello Brian,

I see no reason your design wouldn't work. Lots of drilling and tapping, but that just takes time.

By the way, congratulations on your article in the Sept/Oct issue of Home Shop Machinist. That is a very nice looking steam engine and a well written article.

Regards,

Chuck

 

[CrewCab]

and another way of looking at it is that $70 goes a fair way towards a QCTP in the first place

Have a look at this one as well Brian, Clicky Link 5th one down I think ...........


Here's a piccy ;D

I don't think they use a dovetail, more sort of an eccentric cam to lock it.

Can't see a problem with what you propose, like anything in this game it's all dependant on the accuracy so it's time consuming, but as you say at present that's not a problem so, why not.

hth
CC

 

[mklotz]

$70 for a dovetail cutter seems way over the top. A 1/2" cutter can be had down here for as little as USD 12...

http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=367-0050&PMPXNO=945962

Check with your Canadian discount tooling suppliers. You should be able to do better than $70.

 

[Brian Rupnow]

Crewcab---I went over yesterday to BusyBee tools and looked at their quick change toolpost for $40.00. It looked pretty Mickey Mouse, was not the right height for my lathe, and the centerblock was advertised as "Hardened Steel" with a centerhole too small for the retaining bolt on my lathe. I thought about buying it, modifyying the height to suit my lathe, and trying a carbide drill to open out the center hole, ---Then thought---"Hell, for that much trouble, I may just as well build my own from scratch."

 

[Brian Rupnow]

$70 for a dovetail cutter seems way over the top. A 1/2" cutter can be had down here for as little as USD 12...

http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=367-0050&PMPXNO=945962

Check with your Canadian discount tooling suppliers. You should be able to do better than $70.

Marv---Welcome to Canada, and Canadian prices. I could buy it from USA, Pay the exchange on the dollar, pay the shipping, pay the $25 fee for "Inspection" at customs, pay the provincial and federal sales taxes on it---and still not be any farther ahead.

 

[ozzie46]

Brian, With your skills have you thought about making you own dove tail cutter using a carbide insert? GadgetBuilder showed how he made one on his site.

Try this link

http://www.gadgetbuilder.com/ToolHolders.html

Ron

 

[CrewCab]

and Canadian prices.

Sounds like the UK .................. that $40 QCTP over here is £70, about £125 Canadian dollars, excluding delivery ???

Anyway, that aside I bought one for my 9x20 lathe, all it needed was a sleeve as the centre hole was too large. When I swapped to the Boxford, the centre hole was fine and I just had to make a 6mm packing plate. The unit has performed well imho though I've not had chance to compare it with the type your considering. Must agree though, annealing the centre block, drilling it then re-tempering seems a PITA :

Go for it ........... we might all be making one by Christmas

atb

CC

 

[Lew Hartswick]

CrewCab, That is the one used on the lathes at school or at least the same design.
I think it is a llot easier to make for a home shop than any dovetail. I have even
used a round rod for the male part sliding in a pair of Vs and that works fine too.
90deg Vs are easy Dovetails are hard.
...lew...

 

[mklotz]

36 $C at Busy Bee.

http://busybeetools.ca/cgi-bin/picture10?NTITEM=125305

 

[black85vette]

Brian, I like it. I don't have a dove tail cutter either and this looks like something I could manage.

 

[PhiberOptix]

Brian, With your skills have you thought about making you own dove tail cutter using a carbide insert? GadgetBuilder showed how he made one on his site.

Try this link

http://www.gadgetbuilder.com/ToolHolders.html

Ron

Now thats a damb good idea I may have a go at one that myself THANKS
Andy

 

[tel]

You idea is sound Brian, and has been used plenty of times in the past. A piece of true hex bar making a wonderful jig for milling the angles.

As far as cutters go ... here's a little one I made not long back

 

[Stan]

Brian: There are lots of ways around the freight, duty, tax etc. when buying small items from the US. Envelopes sent first class mail get delivered right to my mail box as long as the shipper put the proper Green US Customs sticker on the envelope. I had a 4" four jaw lathe chuck shipped in a bubble envelope and it came with about $8.00 postage to my mailbox (no duty, tax or customs charge).

Rule #1 - Ship nothing by UPS
Rule #2 - Ship USPS First Class or Flat Rate Box ($23.00 for up to 20 pounds)
Rule #3 - Keep shipments under $100.00 even if you have to split the order.
Rule #4 - Develop a relationship with someone on the South side of the 49th who will accept shipments and reship to you when dealing with companies who refuse to ship to international destinations. HTH Stan

 

[Steelmaster]

Crewcab---I went over yesterday to BusyBee tools and looked at their quick change toolpost for $40.00. It looked pretty Mickey Mouse, was not the right height for my lathe, and the centerblock was advertised as "Hardened Steel" with a centerhole too small for the retaining bolt on my lathe. I thought about buying it, modifyying the height to suit my lathe, and trying a carbide drill to open out the center hole, ---Then thought---"Hell, for that much trouble, I may just as well build my own from scratch."

Then again, $US78 buys you a pretty good QCTP from CDCO with 5 tool holders, including a parting tool holder and a knurling tool holder. Extra tool holders are less than $US10.
So if you want a "poor man's" QCTP I reckon that's the way to go as I doubt whether you could buy the materials, ie metal and socket heads etc for that amount of money.

Now, if you are looking for an interesting project, that would be a different matter.............

 

[Florian]

If the dovetail is big enough, you could also make a dovetail cutter with some carbid reversing plates. I have seen such millers (i can't remember if it was here or on another board)

Anyway, to make your own is also a possibility:
I had to make a very small one for my ball turning attachment some time ago; I used silver steel...: http://www.homemodelenginemachinist.com/index.php?topic=2862.0

Florian

 

[augoldminer]

About 2 week ago someone ask me if i could use a old atlas 7 inch shaper.
I told them yes before anyone else could got it.

My first project had a dovetail and it was just what i needed.
many machinist think shapers are obsolete.

But the three things about shapers are cheap tooling and being able to do dovetails and square holes.

My next project is to replace the old compound rest on my old logan lathe.
The T slot was broken out by a previous owner and braze welded back.
I plan to replace it with one made from mild steel.

 

[Florian]

Shapers also make absolutely perfect surfaces (normally)!
If i had a shaper, i wouldn't mill any dovetail. I would shape them!!

Florian