Re: [CAD_CAM_EDM_DRO] part holding

Howdy Bob;

Sorry, forgot to include my source. I got the recipe from, "Workholding In The
Lathe", by Tubal Cain. A, "turner", is one who works on a lathe. Resin, or
common resin, if memory serves, is simply pine sap, or pitch, warmed up enough
to flow through a filter. A no holes type face plate used in this manner is
generally refered to as a, "shellac chuck". He had another recipe that he said
was stronger, using shellac and powdered pumice, but also mentioned that it was,
"a pig to make". He shows several methods for using shellac on a watchmakers
lathe, and also said that this was a common thing to see in metal working, but
declined in usage somewhere after the turn of the last century. I'd guess that
would probably be due to setup time, and a bit of mess to clean up afterewards.

Bill

On Fri Sep 3 01:30:55 2004 Bob Muse wrote:

>Hi Bill
>
>I have used "superglue" to hold parts, but I've never heard of "turner's
>cement". What exactly is common resin?
>
>Bob
>
>----- Original Message -----
>From: "Bill Vance" <ccq@...>
>To: <CAD_CAM_EDM_DRO@yahoogroups.com>
>Sent: Friday, September 03, 2004 12:40 AM
>Subject: Re: [CAD_CAM_EDM_DRO] part holding
>
>
>> On Thu Sep 2 20:50:35 2004 skykotech wrote:
>>
>> >The hardest part about cnc is not the electronics, the servos, the
>> >ballscrews. The hardest part is holding down the friggen part! I
>> >just ruined yet another brand new 1/2" made-in-usa endmill when my
>> >program had a rapid that went .010 too close to a holddown clamp at
>> >120IPM. Doh! I wouldn't have had things so close to the clamps if
>> >it were not for the fact that I wanted to machine everything at once
>> >without remounting the part. How do you guys hold down a part when
>> >you want to machine 5 surfaces on it? Vacuum table? Glue? :-)
>> >
>> >Good thing Enco still has that free shipping going on...sigh
>>
>> You could try old fashioned, "turners cement". Take 3 parts common resin,
>and
>> one part beeswax, heat slowly, stir well, and pour into stick molds. For
>use on
>> a mill, i'd use a flat piece of metal for clamping, rub the stick on it,
>heat
>> it, and press your work piece down on it till cool. To release it, hold a
>piece
>> of wood against the side, and give it a rap with a hammer. Holding power
>is
>> about 200 pounds per sq. inch.
>>
>> For lathe work, say you wanted to turn some washers to exact thickness,
>you'd
>> want to rub a stick against the face plate, and hold the washers against
>it
>> until warm, and then just let go. Make a very gentle facing cut across
>the
>> washers, pop them loose, reverse, and reapply them to the face plate, and
>then
>> start facing them to thickness.
>>
>> Bill

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