Draw Bar T-Wrench?

[Rikk]

Hope someone can help here, I bought a BF20L (G0704) a few months ago, it came with a draw bar t-wrench with a square hole in the end about 8.3mm square. Been using this quite happily but yesterday the tool broke and I'm finding it impossible to find a replacement or even a square bit to go on a ratchet.

Any pointers as to where I can get one from, in the UK prefurably.

I have emailed the maker but still waiting a responce.

Thanks

                       ...........Rikk

[andyf]

Hi Rikk,

I've got a little plumber's tool like this http://www.screwfix.com/prods/16428/Hand-Tools/Plumbing-Tools/Specialist-Plumbing/Services-Cabinet-Key . Each arm has a different socket on the end. One is a mystery, the second is triangular for opening outdoor gas meter covers, and the third and fourth are square. The larger square one is just over 8.3mm across its internal flats. It measures about 60mm from wingtip to wingtip. Made of rubbish metal, thpugh.

A better plan would be to base something on a bit of round bar. Cut it lengthwise, mill a slot 8.3mm wide and 4.15mm deep into each of the cut faces, then braze the bar back together. That will give you a not quite round bit of bar (because of the kerf) with an 8.3mm square hole through it. I'm sure you could work that idea up into a T wrench.

Andy

[Rikk]

Thanks for the pointers guys, never thought about splitting a rod length ways, neat idea
Hmm actually I might use a bit of rectangular section to make up a square tool, save a little cutting ;)

I'll have to get one of those cheapy ones for now as I don'y have anything to tighten up the draw bar to make it. Can't believe these things are so hard to get.
I had intended using a cheapy electric impact wrench for doing it up and undoing it but as I can't find anything to fit the end that went out of the window.

Out of interest (I've not been doing this long) how tight does the drawbar need to be done up, is it TIGHT, or just just enough to hold the taper in?

[75Plus]

Rikk,

I purchased a BF 20L clone, Grizzly's G0704, and it was only supplied with an 8 X 10mm open ended spanner for the drawbar. There is a picture in the manual showing it being used.

[bigmini]

Rikk,

I purchased a BF 20L clone, Grizzly's G0704, and it was only supplied with an 8 X 10mm open ended spanner for the drawbar. There is a picture in the manual showing it being used.

Thinking outside the box a bit. You could always make another drawbar out of hex bar that will take a socket wrench. My collet chuck didn't come with a drawbar, and I did just that.

[Swarfing]

Is it not possible cut the end off, drill and tap it, add a large socket head bolt and pin it? or turn the bolt down, knurl it, drill the hole just under size and wack it in with some loctite and pin it?

[Rikk]

Didn't even think about replacing it, or a nice big knurled knob would be nice....what that's what she says ;)

How tight should the draw bar be done up?

[bigmini]

Didn't even think about replacing it, or a nice big knurled knob would be nice....what that's what she says ;)

How tight should the draw bar be done up?

Probably not as tight as you could get it with a socket wrench. Perhaps keep the lever arm on whatever you use to do it up to no more than a couple of inches - like a chuck key. I do mine up with a 4" shifter, but the knob sounds like a good idea.

[andyf]

.... How tight should the draw bar be done up?

Not so tight that you break the wrench 

Actually, I found that it was a lot less than I first thought, and that firmly finger tight, and then perhaps another turn, will do the trick for my 2MT spindle. That seems to work OK for my flycutter which sweeps a 2"/50mm circle, and hence exercises a fair bit of leverage. The trouble with overtightening a Morse taper is that you end up banging harder than you want to on the end of the drawbar to get the thing out. I imagine that a more pronounced taper such as R8 is a lot easier in that respect.

Of course, you don't want the tapers to slip, but if they do shift it will tend to tighten the drawbar up.

Andy

[Rikk]

Not so tight that you break the wrench 

The trouble with overtightening a Morse taper is that you end up banging harder than you want to on the end of the drawbar to get the thing out.

Hehe ;p

I had been showing my friend how to use it as he wanted something done and I can't stand up to long at the moment as I've just had my ankle replaced. I'd shown him to loosen it till it bites again then a quick wack to free it up but he forgot the wack, oh well

So a knob it is then, I'm not even going to knurl it so it stops me tightening to far.

This is the kind of silly thing having someone to show you and ask questions of would avoid, I've spent an awful lot of time reading forums, asking questions and sucking n seeing but you still get some plain simple things wrong.....well I do ;)

So on that note, if there's anyone essex/london way who fancies a cup of tea and a chat let me know 

Thanks for the help guys.

[Swarfing]

Rikk those that never do anything wrong never did nothing. You only learn from mistakes so just tell yourself it just cost you a lesson. I've spent a fortune on lessons myself 

[Rikk]

I do enjoy learning by doing, but if you'd of seen me at the start squaring off a bit delrin with a 16mm 2 flute cutter, taking a .1mm cut and turning the feed as slooooow as possible as I had no idea. Took me bloody ages to do anything, now I know much better about feeds and speeds I can't turn the handle fast enough with the same cutter at any cut depth in delrin and not far off in ali 8)